%% =====================================================================
%% This library is free software; you can redistribute it and/or modify
%% it under the terms of the GNU Lesser General Public License as
%% published by the Free Software Foundation; either version 2 of the
%% License, or (at your option) any later version.
%%
%% This library is distributed in the hope that it will be useful, but
%% WITHOUT ANY WARRANTY; without even the implied warranty of
%% MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
%% Lesser General Public License for more details.
%%
%% You should have received a copy of the GNU Lesser General Public
%% License along with this library; if not, write to the Free Software
%% Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
%% USA
%%
%% $Id$
%%
%% @copyright 1997-2006 Richard Carlsson
%% @author Richard Carlsson <[email protected]>
%% @end
%% =====================================================================
%% @doc Abstract Erlang syntax trees.
%%
%% This module defines an abstract data type for representing Erlang
%% source code as syntax trees, in a way that is backwards compatible
%% with the data structures created by the Erlang standard library
%% parser module <code>erl_parse</code> (often referred to as "parse
%% trees", which is a bit of a misnomer). This means that all
%% <code>erl_parse</code> trees are valid abstract syntax trees, but the
%% reverse is not true: abstract syntax trees can in general not be used
%% as input to functions expecting an <code>erl_parse</code> tree.
%% However, as long as an abstract syntax tree represents a correct
%% Erlang program, the function <a
%% href="#revert-1"><code>revert/1</code></a> should be able to
%% transform it to the corresponding <code>erl_parse</code>
%% representation.
%%
%% A recommended starting point for the first-time user is the
%% documentation of the <a
%% href="#type-syntaxTree"><code>syntaxTree()</code></a> data type, and
%% the function <a href="#type-1"><code>type/1</code></a>.
%%
%% <h3><b>NOTES:</b></h3>
%%
%% This module deals with the composition and decomposition of
%% <em>syntactic</em> entities (as opposed to semantic ones); its
%% purpose is to hide all direct references to the data structures used
%% to represent these entities. With few exceptions, the functions in
%% this module perform no semantic interpretation of their inputs, and
%% in general, the user is assumed to pass type-correct arguments - if
%% this is not done, the effects are not defined.
%%
%% With the exception of the <code>erl_parse</code> data structures,
%% the internal representations of abstract syntax trees are subject to
%% change without notice, and should not be documented outside this
%% module. Furthermore, we do not give any guarantees on how an abstract
%% syntax tree may or may not be represented, <em>with the following
%% exceptions</em>: no syntax tree is represented by a single atom, such
%% as <code>none</code>, by a list constructor <code>[X | Y]</code>, or
%% by the empty list <code>[]</code>. This can be relied on when writing
%% functions that operate on syntax trees.
%% @type syntaxTree(). An abstract syntax tree. The
%% <code>erl_parse</code> "parse tree" representation is a subset of the
%% <code>syntaxTree()</code> representation.
%%
%% Every abstract syntax tree node has a <em>type</em>, given by the
%% function <a href="#type-1"><code>type/1</code></a>. Each node also
%% has associated <em>attributes</em>; see <a
%% href="#get_attrs-1"><code>get_attrs/1</code></a> for details. The
%% functions <a href="#make_tree-2"><code>make_tree/2</code></a> and <a
%% href="#subtrees-1"><code>subtrees/1</code></a> are generic
%% constructor/decomposition functions for abstract syntax trees. The
%% functions <a href="#abstract-1"><code>abstract/1</code></a> and <a
%% href="#concrete-1"><code>concrete/1</code></a> convert between
%% constant Erlang terms and their syntactic representations. The set of
%% syntax tree nodes is extensible through the <a
%% href="#tree-2"><code>tree/2</code></a> function.
%%
%% A syntax tree can be transformed to the <code>erl_parse</code>
%% representation with the <a href="#revert-1"><code>revert/1</code></a>
%% function.
-module(erl_syntax).
-export([type/1,
is_leaf/1,
is_form/1,
is_literal/1,
abstract/1,
concrete/1,
revert/1,
revert_forms/1,
subtrees/1,
make_tree/2,
update_tree/2,
meta/1,
get_pos/1,
set_pos/2,
copy_pos/2,
get_precomments/1,
set_precomments/2,
add_precomments/2,
get_postcomments/1,
set_postcomments/2,
add_postcomments/2,
has_comments/1,
remove_comments/1,
copy_comments/2,
join_comments/2,
get_ann/1,
set_ann/2,
add_ann/2,
copy_ann/2,
get_attrs/1,
set_attrs/2,
copy_attrs/2,
flatten_form_list/1,
cons/2,
list_head/1,
list_tail/1,
is_list_skeleton/1,
is_proper_list/1,
list_elements/1,
list_length/1,
normalize_list/1,
compact_list/1,
application/2,
application/3,
application_arguments/1,
application_operator/1,
arity_qualifier/2,
arity_qualifier_argument/1,
arity_qualifier_body/1,
atom/1,
is_atom/2,
atom_value/1,
atom_literal/1,
atom_name/1,
attribute/1,
attribute/2,
attribute_arguments/1,
attribute_name/1,
binary/1,
binary_comp/2,
binary_comp_template/1,
binary_comp_body/1,
binary_field/1,
binary_field/2,
binary_field/3,
binary_field_body/1,
binary_field_types/1,
binary_field_size/1,
binary_fields/1,
binary_generator/2,
binary_generator_body/1,
binary_generator_pattern/1,
block_expr/1,
block_expr_body/1,
case_expr/2,
case_expr_argument/1,
case_expr_clauses/1,
catch_expr/1,
catch_expr_body/1,
char/1,
is_char/2,
char_value/1,
char_literal/1,
clause/2,
clause/3,
clause_body/1,
clause_guard/1,
clause_patterns/1,
comment/1,
comment/2,
comment_padding/1,
comment_text/1,
cond_expr/1,
cond_expr_clauses/1,
conjunction/1,
conjunction_body/1,
disjunction/1,
disjunction_body/1,
eof_marker/0,
error_marker/1,
error_marker_info/1,
float/1,
float_value/1,
float_literal/1,
form_list/1,
form_list_elements/1,
fun_expr/1,
fun_expr_arity/1,
fun_expr_clauses/1,
function/2,
function_arity/1,
function_clauses/1,
function_name/1,
generator/2,
generator_body/1,
generator_pattern/1,
if_expr/1,
if_expr_clauses/1,
implicit_fun/1,
implicit_fun/2,
implicit_fun/3,
implicit_fun_name/1,
infix_expr/3,
infix_expr_left/1,
infix_expr_operator/1,
infix_expr_right/1,
integer/1,
is_integer/2,
integer_value/1,
integer_literal/1,
list/1,
list/2,
list_comp/2,
list_comp_body/1,
list_comp_template/1,
list_prefix/1,
list_suffix/1,
macro/1,
macro/2,
macro_arguments/1,
macro_name/1,
match_expr/2,
match_expr_body/1,
match_expr_pattern/1,
module_qualifier/2,
module_qualifier_argument/1,
module_qualifier_body/1,
nil/0,
operator/1,
operator_literal/1,
operator_name/1,
parentheses/1,
parentheses_body/1,
prefix_expr/2,
prefix_expr_argument/1,
prefix_expr_operator/1,
qualified_name/1,
qualified_name_segments/1,
query_expr/1,
query_expr_body/1,
receive_expr/1,
receive_expr/3,
receive_expr_action/1,
receive_expr_clauses/1,
receive_expr_timeout/1,
record_access/2,
record_access/3,
record_access_argument/1,
record_access_field/1,
record_access_type/1,
record_expr/2,
record_expr/3,
record_expr_argument/1,
record_expr_fields/1,
record_expr_type/1,
record_field/1,
record_field/2,
record_field_name/1,
record_field_value/1,
record_index_expr/2,
record_index_expr_field/1,
record_index_expr_type/1,
rule/2,
rule_arity/1,
rule_clauses/1,
rule_name/1,
size_qualifier/2,
size_qualifier_argument/1,
size_qualifier_body/1,
string/1,
is_string/2,
string_value/1,
string_literal/1,
text/1,
text_string/1,
try_expr/2,
try_expr/3,
try_expr/4,
try_after_expr/2,
try_expr_body/1,
try_expr_clauses/1,
try_expr_handlers/1,
try_expr_after/1,
class_qualifier/2,
class_qualifier_argument/1,
class_qualifier_body/1,
tuple/1,
tuple_elements/1,
tuple_size/1,
underscore/0,
variable/1,
variable_name/1,
variable_literal/1,
warning_marker/1,
warning_marker_info/1,
tree/1,
tree/2,
data/1,
is_tree/1]).
%% =====================================================================
%% IMPLEMENTATION NOTES:
%%
%% All nodes are represented by tuples of arity 2 or greater, whose
%% first element is an atom which uniquely identifies the type of the
%% node. (In the backwards-compatible representation, the interpretation
%% is also often dependent on the context; the second element generally
%% holds the position information - with a couple of exceptions; see
%% `get_pos' and `set_pos' for details). In the documentation of this
%% module, `Pos' is the source code position information associated with
%% a node; usually, this is a positive integer indicating the original
%% source code line, but no assumptions are made in this module
%% regarding the format or interpretation of position information. When
%% a syntax tree node is constructed, its associated position is by
%% default set to the integer zero.
%% =====================================================================
-define(NO_UNUSED, true).
%% =====================================================================
%% Declarations of globally used internal data structures
%% =====================================================================
%% `com' records are used to hold comment information attached to a
%% syntax tree node or a wrapper structure.
%%
%% #com{pre :: Pre, post :: Post}
%%
%% Pre = Post = [Com]
%% Com = syntaxTree()
%%
%% type(Com) = comment
-record(com, {pre = [],
post = []}).
%% `attr' records store node attributes as an aggregate.
%%
%% #attr{pos :: Pos, ann :: Ann, com :: Comments}
%%
%% Pos = term()
%% Ann = [term()]
%% Comments = none | #com{}
%%
%% where `Pos' `Ann' and `Comments' are the corresponding values of a
%% `tree' or `wrapper' record.
-record(attr, {pos = 0,
ann = [],
com = none}).
%% `tree' records represent new-form syntax tree nodes.
%%
%% Tree = #tree{type :: Type, attr :: Attr, data :: Data}
%%
%% Type = atom()
%% Attr = #attr{}
%% Data = term()
%%
%% is_tree(Tree) = true
-record(tree, {type,
attr = #attr{} :: #attr{},
data}).
%% `wrapper' records are used for attaching new-form node information to
%% `erl_parse' trees.
%%
%% Wrapper = #wrapper{type :: Type, attr :: Attr, tree :: ParseTree}
%%
%% Type = atom()
%% Attr = #attr{}
%% ParseTree = term()
%%
%% is_tree(Wrapper) = false
-record(wrapper, {type,
attr = #attr{} :: #attr{},
tree}).
%% =====================================================================
%%
%% Exported functions
%%
%% =====================================================================
%% =====================================================================
%% @spec type(Node::syntaxTree()) -> atom()
%%
%% @doc Returns the type tag of <code>Node</code>. If <code>Node</code>
%% does not represent a syntax tree, evaluation fails with reason
%% <code>badarg</code>. Node types currently defined by this module are:
%% <p><center><table border="1">
%% <tr>
%% <td>application</td>
%% <td>arity_qualifier</td>
%% <td>atom</td>
%% <td>attribute</td>
%% </tr><tr>
%% <td>binary</td>
%% <td>binary_field</td>
%% <td>block_expr</td>
%% <td>case_expr</td>
%% </tr><tr>
%% <td>catch_expr</td>
%% <td>char</td>
%% <td>class_qualifier</td>
%% <td>clause</td>
%% </tr><tr>
%% <td>comment</td>
%% <td>cond_expr</td>
%% <td>conjunction</td>
%% <td>disjunction</td>
%% </tr><tr>
%% <td>eof_marker</td>
%% <td>error_marker</td>
%% <td>float</td>
%% <td>form_list</td>
%% </tr><tr>
%% <td>fun_expr</td>
%% <td>function</td>
%% <td>generator</td>
%% <td>if_expr</td>
%% </tr><tr>
%% <td>implicit_fun</td>
%% <td>infix_expr</td>
%% <td>integer</td>
%% <td>list</td>
%% </tr><tr>
%% <td>list_comp</td>
%% <td>macro</td>
%% <td>match_expr</td>
%% <td>module_qualifier</td>
%% </tr><tr>
%% <td>nil</td>
%% <td>operator</td>
%% <td>parentheses</td>
%% <td>prefix_expr</td>
%% </tr><tr>
%% <td>qualified_name</td>
%% <td>query_expr</td>
%% <td>receive_expr</td>
%% <td>record_access</td>
%% </tr><tr>
%% <td>record_expr</td>
%% <td>record_field</td>
%% <td>record_index_expr</td>
%% <td>rule</td>
%% </tr><tr>
%% <td>size_qualifier</td>
%% <td>string</td>
%% <td>text</td>
%% <td>try_expr</td>
%% </tr><tr>
%% <td>tuple</td>
%% <td>underscore</td>
%% <td>variable</td>
%% <td>warning_marker</td>
%% </tr>
%% </table></center></p>
%% <p>The user may (for special purposes) create additional nodes
%% with other type tags, using the <code>tree/2</code> function.</p>
%%
%% <p>Note: The primary constructor functions for a node type should
%% always have the same name as the node type itself.</p>
%%
%% @see tree/2
%% @see application/3
%% @see arity_qualifier/2
%% @see atom/1
%% @see attribute/2
%% @see binary/1
%% @see binary_field/2
%% @see block_expr/1
%% @see case_expr/2
%% @see catch_expr/1
%% @see char/1
%% @see class_qualifier/2
%% @see clause/3
%% @see comment/2
%% @see cond_expr/1
%% @see conjunction/1
%% @see disjunction/1
%% @see eof_marker/0
%% @see error_marker/1
%% @see float/1
%% @see form_list/1
%% @see fun_expr/1
%% @see function/2
%% @see generator/2
%% @see if_expr/1
%% @see implicit_fun/2
%% @see infix_expr/3
%% @see integer/1
%% @see list/2
%% @see list_comp/2
%% @see macro/2
%% @see match_expr/2
%% @see module_qualifier/2
%% @see nil/0
%% @see operator/1
%% @see parentheses/1
%% @see prefix_expr/2
%% @see qualified_name/1
%% @see query_expr/1
%% @see receive_expr/3
%% @see record_access/3
%% @see record_expr/2
%% @see record_field/2
%% @see record_index_expr/2
%% @see rule/2
%% @see size_qualifier/2
%% @see string/1
%% @see text/1
%% @see try_expr/3
%% @see tuple/1
%% @see underscore/0
%% @see variable/1
%% @see warning_marker/1
type(#tree{type = T}) ->
T;
type(#wrapper{type = T}) ->
T;
type(Node) ->
%% Check for `erl_parse'-compatible nodes, and otherwise fail.
case Node of
%% Leaf types
{atom, _, _} -> atom;
{char, _, _} -> char;
{float, _, _} -> float;
{integer, _, _} -> integer;
{nil, _} -> nil;
{string, _, _} -> string;
{var, _, Name} ->
if Name =:= '_' -> underscore;
true -> variable
end;
{error, _} -> error_marker;
{warning, _} -> warning_marker;
{eof, _} -> eof_marker;
%% Composite types
{'case', _, _, _} -> case_expr;
{'catch', _, _} -> catch_expr;
{'cond', _, _} -> cond_expr;
{'fun', _, {clauses, _}} -> fun_expr;
{'fun', _, {function, _, _}} -> implicit_fun;
{'fun', _, {function, _, _, _}} -> implicit_fun;
{'if', _, _} -> if_expr;
{'receive', _, _, _, _} -> receive_expr;
{'receive', _, _} -> receive_expr;
{attribute, _, _, _} -> attribute;
{bin, _, _} -> binary;
{bin_element, _, _, _, _} -> binary_field;
{block, _, _} -> block_expr;
{call, _, _, _} -> application;
{clause, _, _, _, _} -> clause;
{cons, _, _, _} -> list;
{function, _, _, _, _} -> function;
{b_generate, _, _, _} -> binary_generator;
{generate, _, _, _} -> generator;
{lc, _, _, _} -> list_comp;
{bc, _, _, _} -> binary_comp;
{match, _, _, _} -> match_expr;
{op, _, _, _, _} -> infix_expr;
{op, _, _, _} -> prefix_expr;
{'query', _, _} -> query_expr;
{record, _, _, _, _} -> record_expr;
{record, _, _, _} -> record_expr;
{record_field, _, _, _, _} -> record_access;
{record_field, _, _, _} ->
case is_qualified_name(Node) of
true -> qualified_name;
false -> record_access
end;
{record_index, _, _, _} -> record_index_expr;
{remote, _, _, _} -> module_qualifier;
{rule, _, _, _, _} -> rule;
{'try', _, _, _, _, _} -> try_expr;
{tuple, _, _} -> tuple;
_ ->
erlang:error({badarg, Node})
end.
%% =====================================================================
%% @spec is_leaf(Node::syntaxTree()) -> bool()
%%
%% @doc Returns <code>true</code> if <code>Node</code> is a leaf node,
%% otherwise <code>false</code>. The currently recognised leaf node
%% types are:
%% <p><center><table border="1">
%% <tr>
%% <td><code>atom</code></td>
%% <td><code>char</code></td>
%% <td><code>comment</code></td>
%% <td><code>eof_marker</code></td>
%% <td><code>error_marker</code></td>
%% </tr><tr>
%% <td><code>float</code></td>
%% <td><code>integer</code></td>
%% <td><code>nil</code></td>
%% <td><code>operator</code></td>
%% <td><code>string</code></td>
%% </tr><tr>
%% <td><code>text</code></td>
%% <td><code>underscore</code></td>
%% <td><code>variable</code></td>
%% <td><code>warning_marker</code></td>
%% </tr>
%% </table></center></p>
%% <p>A node of type <code>tuple</code> is a leaf node if and only if
%% its arity is zero.</p>
%%
%% <p>Note: not all literals are leaf nodes, and vice versa. E.g.,
%% tuples with nonzero arity and nonempty lists may be literals, but are
%% not leaf nodes. Variables, on the other hand, are leaf nodes but not
%% literals.</p>
%%
%% @see type/1
%% @see is_literal/1
is_leaf(Node) ->
case type(Node) of
atom -> true;
char -> true;
comment -> true; % nonstandard type
eof_marker -> true;
error_marker -> true;
float -> true;
integer -> true;
nil -> true;
operator -> true; % nonstandard type
string -> true;
text -> true; % nonstandard type
tuple -> tuple_elements(Node) =:= [];
underscore -> true;
variable -> true;
warning_marker -> true;
_ -> false
end.
%% =====================================================================
%% @spec is_form(Node::syntaxTree()) -> bool()
%%
%% @doc Returns <code>true</code> if <code>Node</code> is a syntax tree
%% representing a so-called "source code form", otherwise
%% <code>false</code>. Forms are the Erlang source code units which,
%% placed in sequence, constitute an Erlang program. Current form types
%% are:
%% <p><center><table border="1">
%% <tr>
%% <td><code>attribute</code></td>
%% <td><code>comment</code></td>
%% <td><code>error_marker</code></td>
%% <td><code>eof_marker</code></td>
%% <td><code>form_list</code></td>
%% </tr><tr>
%% <td><code>function</code></td>
%% <td><code>rule</code></td>
%% <td><code>warning_marker</code></td>
%% <td><code>text</code></td>
%% </tr>
%% </table></center></p>
%% @see type/1
%% @see attribute/2
%% @see comment/2
%% @see eof_marker/0
%% @see error_marker/1
%% @see form_list/1
%% @see function/2
%% @see rule/2
%% @see warning_marker/1
is_form(Node) ->
case type(Node) of
attribute -> true;
comment -> true;
function -> true;
eof_marker -> true;
error_marker -> true;
form_list -> true;
rule -> true;
warning_marker -> true;
text -> true;
_ -> false
end.
%% =====================================================================
%% @spec get_pos(Node::syntaxTree()) -> term()
%%
%% @doc Returns the position information associated with
%% <code>Node</code>. This is usually a nonnegative integer (indicating
%% the source code line number), but may be any term. By default, all
%% new tree nodes have their associated position information set to the
%% integer zero.
%%
%% @see set_pos/2
%% @see get_attrs/1
%% All `erl_parse' tree nodes are represented by tuples whose second
%% field is the position information (usually an integer), *with the
%% exceptions of* `{error, ...}' (type `error_marker') and `{warning,
%% ...}' (type `warning_marker'), which only contain the associated line
%% number *of the error descriptor*; this is all handled transparently
%% by `get_pos' and `set_pos'.
get_pos(#tree{attr = Attr}) ->
Attr#attr.pos;
get_pos(#wrapper{attr = Attr}) ->
Attr#attr.pos;
get_pos({error, {Pos, _, _}}) ->
Pos;
get_pos({warning, {Pos, _, _}}) ->
Pos;
get_pos(Node) ->
%% Here, we assume that we have an `erl_parse' node with position
%% information in element 2.
element(2, Node).
%% =====================================================================
%% @spec set_pos(Node::syntaxTree(), Pos::term()) -> syntaxTree()
%%
%% @doc Sets the position information of <code>Node</code> to
%% <code>Pos</code>.
%%
%% @see get_pos/1
%% @see copy_pos/2
set_pos(Node, Pos) ->
case Node of
#tree{attr = Attr} ->
Node#tree{attr = Attr#attr{pos = Pos}};
#wrapper{attr = Attr} ->
Node#wrapper{attr = Attr#attr{pos = Pos}};
_ ->
%% We then assume we have an `erl_parse' node, and create a
%% wrapper around it to make things more uniform.
set_pos(wrap(Node), Pos)
end.
%% =====================================================================
%% @spec copy_pos(Source::syntaxTree(), Target::syntaxTree()) ->
%% syntaxTree()
%%
%% @doc Copies the position information from <code>Source</code> to
%% <code>Target</code>.
%%
%% <p>This is equivalent to <code>set_pos(Target,
%% get_pos(Source))</code>, but potentially more efficient.</p>
%%
%% @see get_pos/1
%% @see set_pos/2
copy_pos(Source, Target) ->
set_pos(Target, get_pos(Source)).
%% =====================================================================
%% `get_com' and `set_com' are for internal use only.
get_com(#tree{attr = Attr}) -> Attr#attr.com;
get_com(#wrapper{attr = Attr}) -> Attr#attr.com;
get_com(_) -> none.
set_com(Node, Com) ->
case Node of
#tree{attr = Attr} ->
Node#tree{attr = Attr#attr{com = Com}};
#wrapper{attr = Attr} ->
Node#wrapper{attr = Attr#attr{com = Com}};
_ ->
set_com(wrap(Node), Com)
end.
%% =====================================================================
%% @spec get_precomments(syntaxTree()) -> [syntaxTree()]
%%
%% @doc Returns the associated pre-comments of a node. This is a
%% possibly empty list of abstract comments, in top-down textual order.
%% When the code is formatted, pre-comments are typically displayed
%% directly above the node. For example:
%% <pre>
%% % Pre-comment of function
%% foo(X) -> {bar, X}.</pre>
%%
%% <p>If possible, the comment should be moved before any preceding
%% separator characters on the same line. E.g.:
%% <pre>
%% foo([X | Xs]) ->
%% % Pre-comment of 'bar(X)' node
%% [bar(X) | foo(Xs)];
%% ...</pre>
%% (where the comment is moved before the "<code>[</code>").</p>
%%
%% @see comment/2
%% @see set_precomments/2
%% @see get_postcomments/1
%% @see get_attrs/1
get_precomments(#tree{attr = Attr}) -> get_precomments_1(Attr);
get_precomments(#wrapper{attr = Attr}) -> get_precomments_1(Attr);
get_precomments(_) -> [].
get_precomments_1(#attr{com = none}) -> [];
get_precomments_1(#attr{com = #com{pre = Cs}}) -> Cs.
%% =====================================================================
%% @spec set_precomments(Node::syntaxTree(),
%% Comments::[syntaxTree()]) -> syntaxTree()
%%
%% @doc Sets the pre-comments of <code>Node</code> to
%% <code>Comments</code>. <code>Comments</code> should be a possibly
%% empty list of abstract comments, in top-down textual order.
%%
%% @see comment/2
%% @see get_precomments/1
%% @see add_precomments/2
%% @see set_postcomments/2
%% @see copy_comments/2
%% @see remove_comments/1
%% @see join_comments/2
set_precomments(Node, Cs) ->
case Node of
#tree{attr = Attr} ->
Node#tree{attr = set_precomments_1(Attr, Cs)};
#wrapper{attr = Attr} ->
Node#wrapper{attr = set_precomments_1(Attr, Cs)};
_ ->
set_precomments(wrap(Node), Cs)
end.
set_precomments_1(#attr{com = none} = Attr, Cs) ->
Attr#attr{com = #com{pre = Cs}};
set_precomments_1(#attr{com = Com} = Attr, Cs) ->
Attr#attr{com = Com#com{pre = Cs}}.
%% =====================================================================
%% @spec add_precomments(Comments::[syntaxTree()],
%% Node::syntaxTree()) -> syntaxTree()
%%
%% @doc Appends <code>Comments</code> to the pre-comments of
%% <code>Node</code>.
%%
%% <p>Note: This is equivalent to <code>set_precomments(Node,
%% get_precomments(Node) ++ Comments)</code>, but potentially more
%% efficient.</p>
%%
%% @see comment/2
%% @see get_precomments/1
%% @see set_precomments/2
%% @see add_postcomments/2
%% @see join_comments/2
add_precomments(Cs, Node) ->
case Node of
#tree{attr = Attr} ->
Node#tree{attr = add_precomments_1(Cs, Attr)};
#wrapper{attr = Attr} ->
Node#wrapper{attr = add_precomments_1(Cs, Attr)};
_ ->
add_precomments(Cs, wrap(Node))
end.
add_precomments_1(Cs, #attr{com = none} = Attr) ->
Attr#attr{com = #com{pre = Cs}};
add_precomments_1(Cs, #attr{com = Com} = Attr) ->
Attr#attr{com = Com#com{pre = Com#com.pre ++ Cs}}.
%% =====================================================================
%% @spec get_postcomments(syntaxTree()) -> [syntaxTree()]
%%
%% @doc Returns the associated post-comments of a node. This is a
%% possibly empty list of abstract comments, in top-down textual order.
%% When the code is formatted, post-comments are typically displayed to
%% the right of and/or below the node. For example:
%% <pre>
%% {foo, X, Y} % Post-comment of tuple</pre>
%%
%% <p>If possible, the comment should be moved past any following
%% separator characters on the same line, rather than placing the
%% separators on the following line. E.g.:
%% <pre>
%% foo([X | Xs], Y) ->
%% foo(Xs, bar(X)); % Post-comment of 'bar(X)' node
%% ...</pre>
%% (where the comment is moved past the rightmost "<code>)</code>" and
%% the "<code>;</code>").</p>
%%
%% @see comment/2
%% @see set_postcomments/2
%% @see get_precomments/1
%% @see get_attrs/1
get_postcomments(#tree{attr = Attr}) -> get_postcomments_1(Attr);
get_postcomments(#wrapper{attr = Attr}) -> get_postcomments_1(Attr);
get_postcomments(_) -> [].
get_postcomments_1(#attr{com = none}) -> [];
get_postcomments_1(#attr{com = #com{post = Cs}}) -> Cs.
%% =====================================================================
%% @spec set_postcomments(Node::syntaxTree(),
%% Comments::[syntaxTree()]) -> syntaxTree()
%%
%% @doc Sets the post-comments of <code>Node</code> to
%% <code>Comments</code>. <code>Comments</code> should be a possibly
%% empty list of abstract comments, in top-down textual order
%%
%% @see comment/2
%% @see get_postcomments/1
%% @see add_postcomments/2
%% @see set_precomments/2
%% @see copy_comments/2
%% @see remove_comments/1
%% @see join_comments/2
set_postcomments(Node, Cs) ->
case Node of
#tree{attr = Attr} ->
Node#tree{attr = set_postcomments_1(Attr, Cs)};
#wrapper{attr = Attr} ->
Node#wrapper{attr = set_postcomments_1(Attr, Cs)};
_ ->
set_postcomments(wrap(Node), Cs)
end.
set_postcomments_1(#attr{com = none} = Attr, Cs) ->
Attr#attr{com = #com{post = Cs}};
set_postcomments_1(#attr{com = Com} = Attr, Cs) ->
Attr#attr{com = Com#com{post = Cs}}.
%% =====================================================================
%% @spec add_postcomments(Comments::[syntaxTree()],
%% Node::syntaxTree()) -> syntaxTree()
%%
%% @doc Appends <code>Comments</code> to the post-comments of
%% <code>Node</code>.
%%
%% <p>Note: This is equivalent to <code>set_postcomments(Node,
%% get_postcomments(Node) ++ Comments)</code>, but potentially more
%% efficient.</p>
%%
%% @see comment/2
%% @see get_postcomments/1
%% @see set_postcomments/2
%% @see add_precomments/2
%% @see join_comments/2
add_postcomments(Cs, Node) ->
case Node of
#tree{attr = Attr} ->
Node#tree{attr = add_postcomments_1(Cs, Attr)};
#wrapper{attr = Attr} ->
Node#wrapper{attr = add_postcomments_1(Cs, Attr)};
_ ->
add_postcomments(Cs, wrap(Node))
end.
add_postcomments_1(Cs, #attr{com = none} = Attr) ->
Attr#attr{com = #com{post = Cs}};
add_postcomments_1(Cs, #attr{com = Com} = Attr) ->
Attr#attr{com = Com#com{post = Com#com.post ++ Cs}}.
%% =====================================================================
%% @spec has_comments(Node::syntaxTree()) -> bool()
%%
%% @doc Yields <code>false</code> if the node has no associated
%% comments, and <code>true</code> otherwise.
%%
%% <p>Note: This is equivalent to <code>(get_precomments(Node) == [])
%% and (get_postcomments(Node) == [])</code>, but potentially more
%% efficient.</p>
%%
%% @see get_precomments/1
%% @see get_postcomments/1
%% @see remove_comments/1
has_comments(#tree{attr = Attr}) ->
case Attr#attr.com of
none -> false;
#com{pre = [], post = []} -> false;
_ -> true
end;
has_comments(#wrapper{attr = Attr}) ->
case Attr#attr.com of
none -> false;
#com{pre = [], post = []} -> false;
_ -> true
end;
has_comments(_) -> false.
%% =====================================================================
%% @spec remove_comments(Node::syntaxTree()) -> syntaxTree()
%%
%% @doc Clears the associated comments of <code>Node</code>.
%%
%% <p>Note: This is equivalent to
%% <code>set_precomments(set_postcomments(Node, []), [])</code>, but
%% potentially more efficient.</p>
%%
%% @see set_precomments/2
%% @see set_postcomments/2
remove_comments(Node) ->
case Node of
#tree{attr = Attr} ->
Node#tree{attr = Attr#attr{com = none}};
#wrapper{attr = Attr} ->
Node#wrapper{attr = Attr#attr{com = none}};
_ ->
Node
end.
%% =====================================================================
%% @spec copy_comments(Source::syntaxTree(), Target::syntaxTree()) ->
%% syntaxTree()
%%
%% @doc Copies the pre- and postcomments from <code>Source</code> to
%% <code>Target</code>.
%%
%% <p>Note: This is equivalent to
%% <code>set_postcomments(set_precomments(Target,
%% get_precomments(Source)), get_postcomments(Source))</code>, but
%% potentially more efficient.</p>
%%
%% @see comment/2
%% @see get_precomments/1
%% @see get_postcomments/1
%% @see set_precomments/2
%% @see set_postcomments/2
copy_comments(Source, Target) ->
set_com(Target, get_com(Source)).
%% =====================================================================
%% @spec join_comments(Source::syntaxTree(), Target::syntaxTree()) ->
%% syntaxTree()
%%
%% @doc Appends the comments of <code>Source</code> to the current
%% comments of <code>Target</code>.
%%
%% <p>Note: This is equivalent to
%% <code>add_postcomments(get_postcomments(Source),
%% add_precomments(get_precomments(Source), Target))</code>, but
%% potentially more efficient.</p>
%%
%% @see comment/2
%% @see get_precomments/1
%% @see get_postcomments/1
%% @see add_precomments/2
%% @see add_postcomments/2
join_comments(Source, Target) ->
add_postcomments(
get_postcomments(Source),
add_precomments(get_precomments(Source), Target)).
%% =====================================================================
%% @spec get_ann(syntaxTree()) -> [term()]
%%
%% @doc Returns the list of user annotations associated with a syntax
%% tree node. For a newly created node, this is the empty list. The
%% annotations may be any terms.
%%
%% @see set_ann/2
%% @see get_attrs/1
get_ann(#tree{attr = Attr}) -> Attr#attr.ann;
get_ann(#wrapper{attr = Attr}) -> Attr#attr.ann;
get_ann(_) -> [].
%% =====================================================================
%% @spec set_ann(Node::syntaxTree(), Annotations::[term()]) ->
%% syntaxTree()
%%
%% @doc Sets the list of user annotations of <code>Node</code> to
%% <code>Annotations</code>.
%%
%% @see get_ann/1
%% @see add_ann/2
%% @see copy_ann/2
set_ann(Node, As) ->
case Node of
#tree{attr = Attr} ->
Node#tree{attr = Attr#attr{ann = As}};
#wrapper{attr = Attr} ->
Node#wrapper{attr = Attr#attr{ann = As}};
_ ->
%% Assume we have an `erl_parse' node and create a wrapper
%% structure to carry the annotation.
set_ann(wrap(Node), As)
end.
%% =====================================================================
%% @spec add_ann(Annotation::term(), Node::syntaxTree()) -> syntaxTree()
%%
%% @doc Appends the term <code>Annotation</code> to the list of user
%% annotations of <code>Node</code>.
%%
%% <p>Note: this is equivalent to <code>set_ann(Node, [Annotation |
%% get_ann(Node)])</code>, but potentially more efficient.</p>
%%
%% @see get_ann/1
%% @see set_ann/2
add_ann(A, Node) ->
case Node of
#tree{attr = Attr} ->
Node#tree{attr = Attr#attr{ann = [A | Attr#attr.ann]}};
#wrapper{attr = Attr} ->
Node#wrapper{attr = Attr#attr{ann = [A | Attr#attr.ann]}};
_ ->
%% Assume we have an `erl_parse' node and create a wrapper
%% structure to carry the annotation.
add_ann(A, wrap(Node))
end.
%% =====================================================================
%% @spec copy_ann(Source::syntaxTree(), Target::syntaxTree()) ->
%% syntaxTree()
%%
%% @doc Copies the list of user annotations from <code>Source</code> to
%% <code>Target</code>.
%%
%% <p>Note: this is equivalent to <code>set_ann(Target,
%% get_ann(Source))</code>, but potentially more efficient.</p>
%%
%% @see get_ann/1
%% @see set_ann/2
copy_ann(Source, Target) ->
set_ann(Target, get_ann(Source)).
%% =====================================================================
%% @spec get_attrs(syntaxTree()) -> syntaxTreeAttributes()
%%
%% @doc Returns a representation of the attributes associated with a
%% syntax tree node. The attributes are all the extra information that
%% can be attached to a node. Currently, this includes position
%% information, source code comments, and user annotations. The result
%% of this function cannot be inspected directly; only attached to
%% another node (cf. <code>set_attrs/2</code>).
%%
%% <p>For accessing individual attributes, see <code>get_pos/1</code>,
%% <code>get_ann/1</code>, <code>get_precomments/1</code> and
%% <code>get_postcomments/1</code>.</p>
%%
%% @type syntaxTreeAttributes(). This is an abstract representation of
%% syntax tree node attributes; see the function <a
%% href="#get_attrs-1"><code>get_attrs/1</code></a>.
%%
%% @see set_attrs/2
%% @see get_pos/1
%% @see get_ann/1
%% @see get_precomments/1
%% @see get_postcomments/1
get_attrs(#tree{attr = Attr}) -> Attr;
get_attrs(#wrapper{attr = Attr}) -> Attr;
get_attrs(Node) -> #attr{pos = get_pos(Node),
ann = get_ann(Node),
com = get_com(Node)}.
%% =====================================================================
%% @spec set_attrs(Node::syntaxTree(),
%% Attributes::syntaxTreeAttributes()) -> syntaxTree()
%%
%% @doc Sets the attributes of <code>Node</code> to
%% <code>Attributes</code>.
%%
%% @see get_attrs/1
%% @see copy_attrs/2
set_attrs(Node, Attr) ->
case Node of
#tree{} ->
Node#tree{attr = Attr};
#wrapper{} ->
Node#wrapper{attr = Attr};
_ ->
set_attrs(wrap(Node), Attr)
end.
%% =====================================================================
%% @spec copy_attrs(Source::syntaxTree(), Target::syntaxTree()) ->
%% syntaxTree()
%%
%% @doc Copies the attributes from <code>Source</code> to
%% <code>Target</code>.
%%
%% <p>Note: this is equivalent to <code>set_attrs(Target,
%% get_attrs(Source))</code>, but potentially more efficient.</p>
%%
%% @see get_attrs/1
%% @see set_attrs/2
copy_attrs(S, T) ->
set_attrs(T, get_attrs(S)).
%% =====================================================================
%% @spec comment(Strings) -> syntaxTree()
%% @equiv comment(none, Strings)
comment(Strings) ->
comment(none, Strings).
%% =====================================================================
%% @spec comment(Padding, Strings::[string()]) -> syntaxTree()
%% Padding = none | integer()
%%
%% @doc Creates an abstract comment with the given padding and text. If
%% <code>Strings</code> is a (possibly empty) list
%% <code>["<em>Txt1</em>", ..., "<em>TxtN</em>"]</code>, the result
%% represents the source code text
%% <pre>
%% %<em>Txt1</em>
%% ...
%% %<em>TxtN</em></pre>
%% <code>Padding</code> states the number of empty character positions
%% to the left of the comment separating it horizontally from
%% source code on the same line (if any). If <code>Padding</code> is
%% <code>none</code>, a default positive number is used. If
%% <code>Padding</code> is an integer less than 1, there should be no
%% separating space. Comments are in themselves regarded as source
%% program forms.
%%
%% @see comment/1
%% @see is_form/1
-record(comment, {pad, text}).
%% type(Node) = comment
%% data(Node) = #comment{pad :: Padding, text :: Strings}
%%
%% Padding = none | integer()
%% Strings = [string()]
comment(Pad, Strings) ->
tree(comment, #comment{pad = Pad, text = Strings}).
%% =====================================================================
%% @spec comment_text(syntaxTree()) -> [string()]
%%
%% @doc Returns the lines of text of the abstract comment.
%%
%% @see comment/2
comment_text(Node) ->
(data(Node))#comment.text.
%% =====================================================================
%% @spec comment_padding(syntaxTree()) -> none | integer()
%%
%% @doc Returns the amount of padding before the comment, or
%% <code>none</code>. The latter means that a default padding may be
%% used.
%%
%% @see comment/2
comment_padding(Node) ->
(data(Node))#comment.pad.
%% =====================================================================
%% @spec form_list(Forms::[syntaxTree()]) -> syntaxTree()
%%
%% @doc Creates an abstract sequence of "source code forms". If
%% <code>Forms</code> is <code>[F1, ..., Fn]</code>, where each
%% <code>Fi</code> is a form (cf. <code>is_form/1</code>, the result
%% represents
%% <pre>
%% <em>F1</em>
%% ...
%% <em>Fn</em></pre>
%% where the <code>Fi</code> are separated by one or more line breaks. A
%% node of type <code>form_list</code> is itself regarded as a source
%% code form; cf. <code>flatten_form_list/1</code>.
%%
%% <p>Note: this is simply a way of grouping source code forms as a
%% single syntax tree, usually in order to form an Erlang module
%% definition.</p>
%%
%% @see form_list_elements/1
%% @see is_form/1
%% @see flatten_form_list/1
%% type(Node) = form_list
%% data(Node) = [Form]
%%
%% Form = syntaxTree()
%% is_form(Form) = true
form_list(Forms) ->
tree(form_list, Forms).
%% =====================================================================
%% @spec form_list_elements(syntaxTree()) -> [syntaxTree()]
%%
%% @doc Returns the list of subnodes of a <code>form_list</code> node.
%%
%% @see form_list/1
form_list_elements(Node) ->
data(Node).
%% =====================================================================
%% @spec flatten_form_list(Node::syntaxTree()) -> syntaxTree()
%%
%% @doc Flattens sublists of a <code>form_list</code> node. Returns
%% <code>Node</code> with all subtrees of type <code>form_list</code>
%% recursively expanded, yielding a single "flat" abstract form
%% sequence.
%%
%% @see form_list/1
flatten_form_list(Node) ->
Fs = form_list_elements(Node),
Fs1 = lists:reverse(flatten_form_list_1(Fs, [])),
copy_attrs(Node, form_list(Fs1)).
flatten_form_list_1([F | Fs], As) ->
case type(F) of
form_list ->
As1 = flatten_form_list_1(form_list_elements(F), As),
flatten_form_list_1(Fs, As1);
_ ->
flatten_form_list_1(Fs, [F | As])
end;
flatten_form_list_1([], As) ->
As.
%% =====================================================================
%% @spec text(String::string()) -> syntaxTree()
%%
%% @doc Creates an abstract piece of source code text. The result
%% represents exactly the sequence of characters in <code>String</code>.
%% This is useful in cases when one wants full control of the resulting
%% output, e.g., for the appearance of floating-point numbers or macro
%% definitions.
%%
%% @see text_string/1
%% type(Node) = text
%% data(Node) = string()
text(String) ->
tree(text, String).
%% =====================================================================
%% @spec text_string(syntaxTree()) -> string()
%%
%% @doc Returns the character sequence represented by a
%% <code>text</code> node.
%%
%% @see text/1
text_string(Node) ->
data(Node).
%% =====================================================================
%% @spec variable(Name) -> syntaxTree()
%% Name = atom() | string()
%%
%% @doc Creates an abstract variable with the given name.
%% <code>Name</code> may be any atom or string that represents a
%% lexically valid variable name, but <em>not</em> a single underscore
%% character; cf. <code>underscore/0</code>.
%%
%% <p>Note: no checking is done whether the character sequence
%% represents a proper variable name, i.e., whether or not its first
%% character is an uppercase Erlang character, or whether it does not
%% contain control characters, whitespace, etc.</p>
%%
%% @see variable_name/1
%% @see variable_literal/1
%% @see underscore/0
%% type(Node) = variable
%% data(Node) = atom()
%%
%% `erl_parse' representation:
%%
%% {var, Pos, Name}
%%
%% Name = atom() \ '_'
variable(Name) when is_atom(Name) ->
tree(variable, Name);
variable(Name) ->
tree(variable, list_to_atom(Name)).
revert_variable(Node) ->
Pos = get_pos(Node),
Name = variable_name(Node),
{var, Pos, Name}.
%% =====================================================================
%% @spec variable_name(syntaxTree()) -> atom()
%%
%% @doc Returns the name of a <code>variable</code> node as an atom.
%%
%% @see variable/1
variable_name(Node) ->
case unwrap(Node) of
{var, _, Name} ->
Name;
Node1 ->
data(Node1)
end.
%% =====================================================================
%% @spec variable_literal(syntaxTree()) -> string()
%%
%% @doc Returns the name of a <code>variable</code> node as a string.
%%
%% @see variable/1
variable_literal(Node) ->
case unwrap(Node) of
{var, _, Name} ->
atom_to_list(Name);
Node1 ->
atom_to_list(data(Node1))
end.
%% =====================================================================
%% @spec underscore() -> syntaxTree()
%%
%% @doc Creates an abstract universal pattern ("<code>_</code>"). The
%% lexical representation is a single underscore character. Note that
%% this is <em>not</em> a variable, lexically speaking.
%%
%% @see variable/1
%% type(Node) = underscore
%% data(Node) = []
%%
%% `erl_parse' representation:
%%
%% {var, Pos, '_'}
underscore() ->
tree(underscore, []).
revert_underscore(Node) ->
Pos = get_pos(Node),
{var, Pos, '_'}.
%% =====================================================================
%% @spec integer(Value::integer()) -> syntaxTree()
%%
%% @doc Creates an abstract integer literal. The lexical representation
%% is the canonical decimal numeral of <code>Value</code>.
%%
%% @see integer_value/1
%% @see integer_literal/1
%% @see is_integer/2
%% type(Node) = integer
%% data(Node) = integer()
%%
%% `erl_parse' representation:
%%
%% {integer, Pos, Value}
%%
%% Value = integer()
integer(Value) ->
tree(integer, Value).
revert_integer(Node) ->
Pos = get_pos(Node),
{integer, Pos, integer_value(Node)}.
%% =====================================================================
%% @spec is_integer(Node::syntaxTree(), Value::integer()) -> bool()
%%
%% @doc Returns <code>true</code> if <code>Node</code> has type
%% <code>integer</code> and represents <code>Value</code>, otherwise
%% <code>false</code>.
%%
%% @see integer/1
is_integer(Node, Value) ->
case unwrap(Node) of
{integer, _, Value} ->
true;
#tree{type = integer, data = Value} ->
true;
_ ->
false
end.
%% =====================================================================
%% @spec integer_value(syntaxTree()) -> integer()
%%
%% @doc Returns the value represented by an <code>integer</code> node.
%%
%% @see integer/1
integer_value(Node) ->
case unwrap(Node) of
{integer, _, Value} ->
Value;
Node1 ->
data(Node1)
end.
%% =====================================================================
%% @spec integer_literal(syntaxTree()) -> string()
%%
%% @doc Returns the numeral string represented by an
%% <code>integer</code> node.
%%
%% @see integer/1
integer_literal(Node) ->
integer_to_list(integer_value(Node)).
%% =====================================================================
%% @spec float(Value::float()) -> syntaxTree()
%%
%% @doc Creates an abstract floating-point literal. The lexical
%% representation is the decimal floating-point numeral of
%% <code>Value</code>.
%%
%% @see float_value/1
%% @see float_literal/1
%% type(Node) = float
%% data(Node) = Value
%%
%% Value = float()
%%
%% `erl_parse' representation:
%%
%% {float, Pos, Value}
%%
%% Value = float()
%% Note that under current versions of Erlang, the name `float/1' cannot
%% be used for local calls (i.e., within the module) - it will be
%% overridden by the type conversion BIF of the same name, so always use
%% `make_float/1' for local calls.
float(Value) ->
make_float(Value).
make_float(Value) ->
tree(float, Value).
revert_float(Node) ->
Pos = get_pos(Node),
{float, Pos, float_value(Node)}.
%% =====================================================================
%% @spec float_value(syntaxTree()) -> float()
%%
%% @doc Returns the value represented by a <code>float</code> node. Note
%% that floating-point values should usually not be compared for
%% equality.
%%
%% @see float/1
float_value(Node) ->
case unwrap(Node) of
{float, _, Value} ->
Value;
Node1 ->
data(Node1)
end.
%% =====================================================================
%% @spec float_literal(syntaxTree()) -> string()
%%
%% @doc Returns the numeral string represented by a <code>float</code>
%% node.
%%
%% @see float/1
float_literal(Node) ->
float_to_list(float_value(Node)).
%% =====================================================================
%% @spec char(Value::char()) -> syntaxTree()
%%
%% @doc Creates an abstract character literal. The result represents
%% "<code>$<em>Name</em></code>", where <code>Name</code> corresponds to
%% <code>Value</code>.
%%
%% <p>Note: the literal corresponding to a particular character value is
%% not uniquely defined. E.g., the character "<code>a</code>" can be
%% written both as "<code>$a</code>" and "<code>$\141</code>", and a Tab
%% character can be written as "<code>$\11</code>", "<code>$\011</code>"
%% or "<code>$\t</code>".</p>
%%
%% @see char_value/1
%% @see char_literal/1
%% @see is_char/2
%% type(Node) = char
%% data(Node) = char()
%%
%% `erl_parse' representation:
%%
%% {char, Pos, Code}
%%
%% Code = integer()
char(Char) ->
tree(char, Char).
revert_char(Node) ->
Pos = get_pos(Node),
{char, Pos, char_value(Node)}.
%% =====================================================================
%% @spec is_char(Node::syntaxTree(), Value::char()) -> bool()
%%
%% @doc Returns <code>true</code> if <code>Node</code> has type
%% <code>char</code> and represents <code>Value</code>, otherwise
%% <code>false</code>.
%%
%% @see char/1
is_char(Node, Value) ->
case unwrap(Node) of
{char, _, Value} ->
true;
#tree{type = char, data = Value} ->
true;
_ ->
false
end.
%% =====================================================================
%% @spec char_value(syntaxTree()) -> char()
%%
%% @doc Returns the value represented by a <code>char</code> node.
%%
%% @see char/1
char_value(Node) ->
case unwrap(Node) of
{char, _, Char} ->
Char;
Node1 ->
data(Node1)
end.
%% =====================================================================
%% @spec char_literal(syntaxTree()) -> string()
%%
%% @doc Returns the literal string represented by a <code>char</code>
%% node. This includes the leading "<code>$</code>" character.
%%
%% @see char/1
char_literal(Node) ->
io_lib:write_char(char_value(Node)).
%% =====================================================================
%% @spec string(Value::string()) -> syntaxTree()
%%
%% @doc Creates an abstract string literal. The result represents
%% <code>"<em>Text</em>"</code> (including the surrounding
%% double-quotes), where <code>Text</code> corresponds to the sequence
%% of characters in <code>Value</code>, but not representing a
%% <em>specific</em> string literal. E.g., the result of
%% <code>string("x\ny")</code> represents any and all of
%% <code>"x\ny"</code>, <code>"x\12y"</code>, <code>"x\012y"</code> and
%% <code>"x\^Jy"</code>; cf. <code>char/1</code>.
%%
%% @see string_value/1
%% @see string_literal/1
%% @see is_string/2
%% @see char/1
%% type(Node) = string
%% data(Node) = string()
%%
%% `erl_parse' representation:
%%
%% {string, Pos, Chars}
%%
%% Chars = string()
string(String) ->
tree(string, String).
revert_string(Node) ->
Pos = get_pos(Node),
{string, Pos, string_value(Node)}.
%% =====================================================================
%% @spec is_string(Node::syntaxTree(), Value::string()) -> bool()
%%
%% @doc Returns <code>true</code> if <code>Node</code> has type
%% <code>string</code> and represents <code>Value</code>, otherwise
%% <code>false</code>.
%%
%% @see string/1
is_string(Node, Value) ->
case unwrap(Node) of
{string, _, Value} ->
true;
#tree{type = string, data = Value} ->
true;
_ ->
false
end.
%% =====================================================================
%% @spec string_value(syntaxTree()) -> string()
%%
%% @doc Returns the value represented by a <code>string</code> node.
%%
%% @see string/1
string_value(Node) ->
case unwrap(Node) of
{string, _, List} ->
List;
Node1 ->
data(Node1)
end.
%% =====================================================================
%% @spec string_literal(syntaxTree()) -> string()
%%
%% @doc Returns the literal string represented by a <code>string</code>
%% node. This includes surrounding double-quote characters.
%%
%% @see string/1
string_literal(Node) ->
io_lib:write_string(string_value(Node)).
%% =====================================================================
%% @spec atom(Name) -> syntaxTree()
%% Name = atom() | string()
%%
%% @doc Creates an abstract atom literal. The print name of the atom is
%% the character sequence represented by <code>Name</code>.
%%
%% @see atom_value/1
%% @see atom_name/1
%% @see atom_literal/1
%% @see is_atom/2
%% type(Node) = atom
%% data(Node) = atom()
%%
%% `erl_parse' representation:
%%
%% {atom, Pos, Value}
%%
%% Value = atom()
atom(Name) when is_atom(Name) ->
tree(atom, Name);
atom(Name) ->
tree(atom, list_to_atom(Name)).
revert_atom(Node) ->
Pos = get_pos(Node),
{atom, Pos, atom_value(Node)}.
%% =====================================================================
%% @spec is_atom(Node::syntaxTree(), Value::atom()) -> bool()
%%
%% @doc Returns <code>true</code> if <code>Node</code> has type
%% <code>atom</code> and represents <code>Value</code>, otherwise
%% <code>false</code>.
%%
%% @see atom/1
is_atom(Node, Value) ->
case unwrap(Node) of
{atom, _, Value} ->
true;
#tree{type = atom, data = Value} ->
true;
_ ->
false
end.
%% =====================================================================
%% @spec atom_value(syntaxTree()) -> atom()
%%
%% @doc Returns the value represented by an <code>atom</code> node.
%%
%% @see atom/1
atom_value(Node) ->
case unwrap(Node) of
{atom, _, Name} ->
Name;
Node1 ->
data(Node1)
end.
%% =====================================================================
%% @spec atom_name(syntaxTree()) -> string()
%%
%% @doc Returns the printname of an <code>atom</code> node.
%%
%% @see atom/1
atom_name(Node) ->
atom_to_list(atom_value(Node)).
%% =====================================================================
%% @spec atom_literal(syntaxTree()) -> string()
%%
%% @doc Returns the literal string represented by an <code>atom</code>
%% node. This includes surrounding single-quote characters if necessary.
%%
%% <p>Note that e.g. the result of <code>atom("x\ny")</code> represents
%% any and all of <code>'x\ny'</code>, <code>'x\12y'</code>,
%% <code>'x\012y'</code> and <code>'x\^Jy\'</code>; cf.
%% <code>string/1</code>.</p>
%%
%% @see atom/1
%% @see string/1
atom_literal(Node) ->
io_lib:write_atom(atom_value(Node)).
%% =====================================================================
%% @spec tuple(Elements::[syntaxTree()]) -> syntaxTree()
%%
%% @doc Creates an abstract tuple. If <code>Elements</code> is
%% <code>[X1, ..., Xn]</code>, the result represents
%% "<code>{<em>X1</em>, ..., <em>Xn</em>}</code>".
%%
%% <p>Note: The Erlang language has distinct 1-tuples, i.e.,
%% <code>{X}</code> is always distinct from <code>X</code> itself.</p>
%%
%% @see tuple_elements/1
%% @see tuple_size/1
%% type(Node) = tuple
%% data(Node) = Elements
%%
%% Elements = [syntaxTree()]
%%
%% `erl_parse' representation:
%%
%% {tuple, Pos, Elements}
%%
%% Elements = [erl_parse()]
tuple(List) ->
tree(tuple, List).
revert_tuple(Node) ->
Pos = get_pos(Node),
{tuple, Pos, tuple_elements(Node)}.
%% =====================================================================
%% @spec tuple_elements(syntaxTree()) -> [syntaxTree()]
%%
%% @doc Returns the list of element subtrees of a <code>tuple</code>
%% node.
%%
%% @see tuple/1
tuple_elements(Node) ->
case unwrap(Node) of
{tuple, _, List} ->
List;
Node1 ->
data(Node1)
end.
%% =====================================================================
%% @spec tuple_size(syntaxTree()) -> integer()
%%
%% @doc Returns the number of elements of a <code>tuple</code> node.
%%
%% <p>Note: this is equivalent to
%% <code>length(tuple_elements(Node))</code>, but potentially more
%% efficient.</p>
%%
%% @see tuple/1
%% @see tuple_elements/1
tuple_size(Node) ->
length(tuple_elements(Node)).
%% =====================================================================
%% @spec list(List) -> syntaxTree()
%% @equiv list(List, none)
list(List) ->
list(List, none).
%% =====================================================================
%% @spec list(List, Tail) -> syntaxTree()
%% List = [syntaxTree()]
%% Tail = none | syntaxTree()
%%
%% @doc Constructs an abstract list skeleton. The result has type
%% <code>list</code> or <code>nil</code>. If <code>List</code> is a
%% nonempty list <code>[E1, ..., En]</code>, the result has type
%% <code>list</code> and represents either "<code>[<em>E1</em>, ...,
%% <em>En</em>]</code>", if <code>Tail</code> is <code>none</code>, or
%% otherwise "<code>[<em>E1</em>, ..., <em>En</em> |
%% <em>Tail</em>]</code>". If <code>List</code> is the empty list,
%% <code>Tail</code> <em>must</em> be <code>none</code>, and in that
%% case the result has type <code>nil</code> and represents
%% "<code>[]</code>" (cf. <code>nil/0</code>).
%%
%% <p>The difference between lists as semantic objects (built up of
%% individual "cons" and "nil" terms) and the various syntactic forms
%% for denoting lists may be bewildering at first. This module provides
%% functions both for exact control of the syntactic representation as
%% well as for the simple composition and deconstruction in terms of
%% cons and head/tail operations.</p>
%%
%% <p>Note: in <code>list(Elements, none)</code>, the "nil" list
%% terminator is implicit and has no associated information (cf.
%% <code>get_attrs/1</code>), while in the seemingly equivalent
%% <code>list(Elements, Tail)</code> when <code>Tail</code> has type
%% <code>nil</code>, the list terminator subtree <code>Tail</code> may
%% have attached attributes such as position, comments, and annotations,
%% which will be preserved in the result.</p>
%%
%% @see nil/0
%% @see list/1
%% @see list_prefix/1
%% @see list_suffix/1
%% @see cons/2
%% @see list_head/1
%% @see list_tail/1
%% @see is_list_skeleton/1
%% @see is_proper_list/1
%% @see list_elements/1
%% @see list_length/1
%% @see normalize_list/1
%% @see compact_list/1
%% @see get_attrs/1
-record(list, {prefix, suffix}).
%% type(Node) = list
%% data(Node) = #list{prefix :: Elements, suffix :: Tail}
%%
%% Elements = [syntaxTree()]
%% Tail = none | syntaxTree()
%%
%% `erl_parse' representation:
%%
%% {cons, Pos, Head, Tail}
%%
%% Head = Tail = [erl_parse()]
%%
%% This represents `[<Head> | <Tail>]', or more generally `[<Head>
%% <Suffix>]' where the form of <Suffix> can depend on the
%% structure of <Tail>; there is no fixed printed form.
list([], none) ->
nil();
list(Elements, Tail) when Elements /= [] ->
tree(list, #list{prefix = Elements, suffix = Tail}).
revert_list(Node) ->
Pos = get_pos(Node),
P = list_prefix(Node),
S = case list_suffix(Node) of
none ->
revert_nil(set_pos(nil(), Pos));
S1 ->
S1
end,
lists:foldr(fun (X, A) ->
{cons, Pos, X, A}
end,
S, P).
%% =====================================================================
%% @spec nil() -> syntaxTree()
%%
%% @doc Creates an abstract empty list. The result represents
%% "<code>[]</code>". The empty list is traditionally called "nil".
%%
%% @see list/2
%% @see is_list_skeleton/1
%% type(Node) = nil
%% data(Node) = term()
%%
%% `erl_parse' representation:
%%
%% {nil, Pos}
nil() ->
tree(nil).
revert_nil(Node) ->
Pos = get_pos(Node),
{nil, Pos}.
%% =====================================================================
%% @spec list_prefix(Node::syntaxTree()) -> [syntaxTree()]
%%
%% @doc Returns the prefix element subtrees of a <code>list</code> node.
%% If <code>Node</code> represents "<code>[<em>E1</em>, ...,
%% <em>En</em>]</code>" or "<code>[<em>E1</em>, ..., <em>En</em> |
%% <em>Tail</em>]</code>", the returned value is <code>[E1, ...,
%% En]</code>.
%%
%% @see list/2
list_prefix(Node) ->
case unwrap(Node) of
{cons, _, Head, _} ->
[Head];
Node1 ->
(data(Node1))#list.prefix
end.
%% =====================================================================
%% @spec list_suffix(Node::syntaxTree()) -> none | syntaxTree()
%%
%% @doc Returns the suffix subtree of a <code>list</code> node, if one
%% exists. If <code>Node</code> represents "<code>[<em>E1</em>, ...,
%% <em>En</em> | <em>Tail</em>]</code>", the returned value is
%% <code>Tail</code>, otherwise, i.e., if <code>Node</code> represents
%% "<code>[<em>E1</em>, ..., <em>En</em>]</code>", <code>none</code> is
%% returned.
%%
%% <p>Note that even if this function returns some <code>Tail</code>
%% that is not <code>none</code>, the type of <code>Tail</code> can be
%% <code>nil</code>, if the tail has been given explicitly, and the list
%% skeleton has not been compacted (cf.
%% <code>compact_list/1</code>).</p>
%%
%% @see list/2
%% @see nil/0
%% @see compact_list/1
list_suffix(Node) ->
case unwrap(Node) of
{cons, _, _, Tail} ->
%% If there could be comments/annotations on the tail node,
%% we should not return `none' even if it has type `nil'.
case Tail of
{nil, _} ->
none; % no interesting information is lost
_ ->
Tail
end;
Node1 ->
(data(Node1))#list.suffix
end.
%% =====================================================================
%% @spec cons(Head::syntaxTree(), Tail::syntaxTree()) -> syntaxTree()
%%
%% @doc "Optimising" list skeleton cons operation. Creates an abstract
%% list skeleton whose first element is <code>Head</code> and whose tail
%% corresponds to <code>Tail</code>. This is similar to
%% <code>list([Head], Tail)</code>, except that <code>Tail</code> may
%% not be <code>none</code>, and that the result does not necessarily
%% represent exactly "<code>[<em>Head</em> | <em>Tail</em>]</code>", but
%% may depend on the <code>Tail</code> subtree. E.g., if
%% <code>Tail</code> represents <code>[X, Y]</code>, the result may
%% represent "<code>[<em>Head</em>, X, Y]</code>", rather than
%% "<code>[<em>Head</em> | [X, Y]]</code>". Annotations on
%% <code>Tail</code> itself may be lost if <code>Tail</code> represents
%% a list skeleton, but comments on <code>Tail</code> are propagated to
%% the result.
%%
%% @see list/2
%% @see list_head/1
%% @see list_tail/1
cons(Head, Tail) ->
case type(Tail) of
list ->
copy_comments(Tail, list([Head | list_prefix(Tail)],
list_suffix(Tail)));
nil ->
copy_comments(Tail, list([Head]));
_ ->
list([Head], Tail)
end.
%% =====================================================================
%% @spec list_head(Node::syntaxTree()) -> syntaxTree()
%%
%% @doc Returns the head element subtree of a <code>list</code> node. If
%% <code>Node</code> represents "<code>[<em>Head</em> ...]</code>", the
%% result will represent "<code><em>Head</em></code>".
%%
%% @see list/2
%% @see list_tail/1
%% @see cons/2
list_head(Node) ->
hd(list_prefix(Node)).
%% =====================================================================
%% @spec list_tail(Node::syntaxTree()) -> syntaxTree()
%%
%% @doc Returns the tail of a <code>list</code> node. If
%% <code>Node</code> represents a single-element list
%% "<code>[<em>E</em>]</code>", then the result has type
%% <code>nil</code>, representing "<code>[]</code>". If
%% <code>Node</code> represents "<code>[<em>E1</em>, <em>E2</em>
%% ...]</code>", the result will represent "<code>[<em>E2</em>
%% ...]</code>", and if <code>Node</code> represents
%% "<code>[<em>Head</em> | <em>Tail</em>]</code>", the result will
%% represent "<code><em>Tail</em></code>".
%%
%% @see list/2
%% @see list_head/1
%% @see cons/2
list_tail(Node) ->
Tail = list_suffix(Node),
case tl(list_prefix(Node)) of
[] ->
if Tail =:= none ->
nil(); % implicit list terminator.
true ->
Tail
end;
Es ->
list(Es, Tail) % `Es' is nonempty.
end.
%% =====================================================================
%% @spec is_list_skeleton(syntaxTree()) -> bool()
%%
%% @doc Returns <code>true</code> if <code>Node</code> has type
%% <code>list</code> or <code>nil</code>, otherwise <code>false</code>.
%%
%% @see list/2
%% @see nil/0
is_list_skeleton(Node) ->
case type(Node) of
list -> true;
nil -> true;
_ -> false
end.
%% =====================================================================
%% @spec is_proper_list(Node::syntaxTree()) -> bool()
%%
%% @doc Returns <code>true</code> if <code>Node</code> represents a
%% proper list, and <code>false</code> otherwise. A proper list is a
%% list skeleton either on the form "<code>[]</code>" or
%% "<code>[<em>E1</em>, ..., <em>En</em>]</code>", or "<code>[... |
%% <em>Tail</em>]</code>" where recursively <code>Tail</code> also
%% represents a proper list.
%%
%% <p>Note: Since <code>Node</code> is a syntax tree, the actual
%% run-time values corresponding to its subtrees may often be partially
%% or completely unknown. Thus, if <code>Node</code> represents e.g.
%% "<code>[... | Ns]</code>" (where <code>Ns</code> is a variable), then
%% the function will return <code>false</code>, because it is not known
%% whether <code>Ns</code> will be bound to a list at run-time. If
%% <code>Node</code> instead represents e.g. "<code>[1, 2, 3]</code>" or
%% "<code>[A | []]</code>", then the function will return
%% <code>true</code>.</p>
%%
%% @see list/2
is_proper_list(Node) ->
case type(Node) of
list ->
case list_suffix(Node) of
none ->
true;
Tail ->
is_proper_list(Tail)
end;
nil ->
true;
_ ->
false
end.
%% =====================================================================
%% @spec list_elements(Node::syntaxTree()) -> [syntaxTree()]
%%
%% @doc Returns the list of element subtrees of a list skeleton.
%% <code>Node</code> must represent a proper list. E.g., if
%% <code>Node</code> represents "<code>[<em>X1</em>, <em>X2</em> |
%% [<em>X3</em>, <em>X4</em> | []]</code>", then
%% <code>list_elements(Node)</code> yields the list <code>[X1, X2, X3,
%% X4]</code>.
%%
%% @see list/2
%% @see is_proper_list/1
list_elements(Node) ->
lists:reverse(list_elements(Node, [])).
list_elements(Node, As) ->
case type(Node) of
list ->
As1 = lists:reverse(list_prefix(Node)) ++ As,
case list_suffix(Node) of
none ->
As1;
Tail ->
list_elements(Tail, As1)
end;
nil ->
As
end.
%% =====================================================================
%% @spec list_length(Node::syntaxTree()) -> integer()
%%
%% @doc Returns the number of element subtrees of a list skeleton.
%% <code>Node</code> must represent a proper list. E.g., if
%% <code>Node</code> represents "<code>[X1 | [X2, X3 | [X4, X5,
%% X6]]]</code>", then <code>list_length(Node)</code> returns the
%% integer 6.
%%
%% <p>Note: this is equivalent to
%% <code>length(list_elements(Node))</code>, but potentially more
%% efficient.</p>
%%
%% @see list/2
%% @see is_proper_list/1
%% @see list_elements/1
list_length(Node) ->
list_length(Node, 0).
list_length(Node, A) ->
case type(Node) of
list ->
A1 = length(list_prefix(Node)) + A,
case list_suffix(Node) of
none ->
A1;
Tail ->
list_length(Tail, A1)
end;
nil ->
A
end.
%% =====================================================================
%% @spec normalize_list(Node::syntaxTree()) -> syntaxTree()
%%
%% @doc Expands an abstract list skeleton to its most explicit form. If
%% <code>Node</code> represents "<code>[<em>E1</em>, ..., <em>En</em> |
%% <em>Tail</em>]</code>", the result represents "<code>[<em>E1</em> |
%% ... [<em>En</em> | <em>Tail1</em>] ... ]</code>", where
%% <code>Tail1</code> is the result of
%% <code>normalize_list(Tail)</code>. If <code>Node</code> represents
%% "<code>[<em>E1</em>, ..., <em>En</em>]</code>", the result simply
%% represents "<code>[<em>E1</em> | ... [<em>En</em> | []] ...
%% ]</code>". If <code>Node</code> does not represent a list skeleton,
%% <code>Node</code> itself is returned.
%%
%% @see list/2
%% @see compact_list/1
normalize_list(Node) ->
case type(Node) of
list ->
P = list_prefix(Node),
case list_suffix(Node) of
none ->
copy_attrs(Node, normalize_list_1(P, nil()));
Tail ->
Tail1 = normalize_list(Tail),
copy_attrs(Node, normalize_list_1(P, Tail1))
end;
_ ->
Node
end.
normalize_list_1(Es, Tail) ->
lists:foldr(fun (X, A) ->
list([X], A) % not `cons'!
end,
Tail, Es).
%% =====================================================================
%% @spec compact_list(Node::syntaxTree()) -> syntaxTree()
%%
%% @doc Yields the most compact form for an abstract list skeleton. The
%% result either represents "<code>[<em>E1</em>, ..., <em>En</em> |
%% <em>Tail</em>]</code>", where <code>Tail</code> is not a list
%% skeleton, or otherwise simply "<code>[<em>E1</em>, ...,
%% <em>En</em>]</code>". Annotations on subtrees of <code>Node</code>
%% that represent list skeletons may be lost, but comments will be
%% propagated to the result. Returns <code>Node</code> itself if
%% <code>Node</code> does not represent a list skeleton.
%%
%% @see list/2
%% @see normalize_list/1
compact_list(Node) ->
case type(Node) of
list ->
case list_suffix(Node) of
none ->
Node;
Tail ->
case type(Tail) of
list ->
Tail1 = compact_list(Tail),
Node1 = list(list_prefix(Node) ++
list_prefix(Tail1),
list_suffix(Tail1)),
join_comments(Tail1,
copy_attrs(Node,
Node1));
nil ->
Node1 = list(list_prefix(Node)),
join_comments(Tail,
copy_attrs(Node,
Node1));
_ ->
Node
end
end;
_ ->
Node
end.
%% =====================================================================
%% @spec binary(Fields::[syntaxTree()]) -> syntaxTree()
%%
%% @doc Creates an abstract binary-object template. If
%% <code>Fields</code> is <code>[F1, ..., Fn]</code>, the result
%% represents "<code><<<em>F1</em>, ...,
%% <em>Fn</em>>></code>".
%%
%% @see binary_fields/1
%% @see binary_field/2
%% type(Node) = binary
%% data(Node) = Fields
%%
%% Fields = [syntaxTree()]
%%
%% `erl_parse' representation:
%%
%% {bin, Pos, Fields}
%%
%% Fields = [Field]
%% Field = {bin_element, ...}
%%
%% See `binary_field' for documentation on `erl_parse' binary
%% fields (or "elements").
binary(List) ->
tree(binary, List).
revert_binary(Node) ->
Pos = get_pos(Node),
{bin, Pos, binary_fields(Node)}.
%% =====================================================================
%% @spec binary_fields(syntaxTree()) -> [syntaxTree()]
%%
%% @doc Returns the list of field subtrees of a <code>binary</code>
%% node.
%%
%% @see binary/1
%% @see binary_field/2
binary_fields(Node) ->
case unwrap(Node) of
{bin, _, List} ->
List;
Node1 ->
data(Node1)
end.
%% =====================================================================
%% @spec binary_field(Body) -> syntaxTree()
%% @equiv binary_field(Body, [])
binary_field(Body) ->
binary_field(Body, []).
%% =====================================================================
%% @spec binary_field(Body::syntaxTree(), Size,
%% Types::[syntaxTree()]) -> syntaxTree()
%% Size = none | syntaxTree()
%%
%% @doc Creates an abstract binary template field.
%% If <code>Size</code> is <code>none</code>, this is equivalent to
%% "<code>binary_field(Body, Types)</code>", otherwise it is
%% equivalent to "<code>binary_field(size_qualifier(Body, Size),
%% Types)</code>".
%%
%% (This is a utility function.)
%%
%% @see binary/1
%% @see binary_field/2
%% @see size_qualifier/2
binary_field(Body, none, Types) ->
binary_field(Body, Types);
binary_field(Body, Size, Types) ->
binary_field(size_qualifier(Body, Size), Types).
%% =====================================================================
%% @spec binary_field(Body::syntaxTree(), Types::[syntaxTree()]) ->
%% syntaxTree()
%%
%% @doc Creates an abstract binary template field. If
%% <code>Types</code> is the empty list, the result simply represents
%% "<code><em>Body</em></code>", otherwise, if <code>Types</code> is
%% <code>[T1, ..., Tn]</code>, the result represents
%% "<code><em>Body</em>/<em>T1</em>-...-<em>Tn</em></code>".
%%
%% @see binary/1
%% @see binary_field/1
%% @see binary_field/3
%% @see binary_field_body/1
%% @see binary_field_types/1
%% @see binary_field_size/1
-record(binary_field, {body, types}).
%% type(Node) = binary_field
%% data(Node) = #binary_field{body :: Body, types :: Types}
%%
%% Body = syntaxTree()
%% Types = [Type]
%%
%% `erl_parse' representation:
%%
%% {bin_element, Pos, Expr, Size, TypeList}
%%
%% Expr = erl_parse()
%% Size = default | erl_parse()
%% TypeList = default | [Type] \ []
%% Type = atom() | {atom(), integer()}
binary_field(Body, Types) ->
tree(binary_field, #binary_field{body = Body, types = Types}).
revert_binary_field(Node) ->
Pos = get_pos(Node),
Body = binary_field_body(Node),
{Expr, Size} = case type(Body) of
size_qualifier ->
%% Note that size qualifiers are not
%% revertible out of context.
{size_qualifier_body(Body),
size_qualifier_argument(Body)};
_ ->
{Body, default}
end,
Types = case binary_field_types(Node) of
[] ->
default;
Ts ->
fold_binary_field_types(Ts)
end,
{bin_element, Pos, Expr, Size, Types}.
%% =====================================================================
%% @spec binary_field_body(syntaxTree()) -> syntaxTree()
%%
%% @doc Returns the body subtree of a <code>binary_field</code>.
%%
%% @see binary_field/2
binary_field_body(Node) ->
case unwrap(Node) of
{bin_element, _, Body, Size, _} ->
if Size =:= default ->
Body;
true ->
size_qualifier(Body, Size)
end;
Node1 ->
(data(Node1))#binary_field.body
end.
%% =====================================================================
%% @spec binary_field_types(Node::syntaxTree()) -> [syntaxTree()]
%%
%% @doc Returns the list of type-specifier subtrees of a
%% <code>binary_field</code> node. If <code>Node</code> represents
%% "<code>.../<em>T1</em>, ..., <em>Tn</em></code>", the result is
%% <code>[T1, ..., Tn]</code>, otherwise the result is the empty list.
%%
%% @see binary_field/2
binary_field_types(Node) ->
case unwrap(Node) of
{bin_element, Pos, _, _, Types} ->
if Types =:= default ->
[];
true ->
unfold_binary_field_types(Types, Pos)
end;
Node1 ->
(data(Node1))#binary_field.types
end.
%% =====================================================================
%% @spec binary_field_size(Node::syntaxTree()) -> none | syntaxTree()
%%
%% @doc Returns the size specifier subtree of a
%% <code>binary_field</code> node, if any. If <code>Node</code>
%% represents "<code><em>Body</em>:<em>Size</em></code>" or
%% "<code><em>Body</em>:<em>Size</em>/<em>T1</em>, ...,
%% <em>Tn</em></code>", the result is <code>Size</code>, otherwise
%% <code>none</code> is returned.
%%
%% (This is a utility function.)
%%
%% @see binary_field/2
%% @see binary_field/3
binary_field_size(Node) ->
case unwrap(Node) of
{bin_element, _, _, Size, _} ->
if Size =:= default ->
none;
true ->
Size
end;
Node1 ->
Body = (data(Node1))#binary_field.body,
case type(Body) of
size_qualifier ->
size_qualifier_argument(Body);
_ ->
none
end
end.
%% =====================================================================
%% @spec size_qualifier(Body::syntaxTree(), Size::syntaxTree()) ->
%% syntaxTree()
%%
%% @doc Creates an abstract size qualifier. The result represents
%% "<code><em>Body</em>:<em>Size</em></code>".
%%
%% @see size_qualifier_body/1
%% @see size_qualifier_argument/1
-record(size_qualifier, {body, size}).
%% type(Node) = size_qualifier
%% data(Node) = #size_qualifier{body :: Body, size :: Size}
%%
%% Body = Size = syntaxTree()
size_qualifier(Body, Size) ->
tree(size_qualifier,
#size_qualifier{body = Body, size = Size}).
%% =====================================================================
%% @spec size_qualifier_body(syntaxTree()) -> syntaxTree()
%%
%% @doc Returns the body subtree of a <code>size_qualifier</code>
%% node.
%%
%% @see size_qualifier/2
size_qualifier_body(Node) ->
(data(Node))#size_qualifier.body.
%% =====================================================================
%% @spec size_qualifier_argument(syntaxTree()) -> syntaxTree()
%%
%% @doc Returns the argument subtree (the size) of a
%% <code>size_qualifier</code> node.
%%
%% @see size_qualifier/2
size_qualifier_argument(Node) ->
(data(Node))#size_qualifier.size.
%% =====================================================================
%% @spec error_marker(Error::term()) -> syntaxTree()
%%
%% @doc Creates an abstract error marker. The result represents an
%% occurrence of an error in the source code, with an associated Erlang
%% I/O ErrorInfo structure given by <code>Error</code> (see module
%% {@link //stdlib/io} for details). Error markers are regarded as source
%% code forms, but have no defined lexical form.
%%
%% <p>Note: this is supported only for backwards compatibility with
%% existing parsers and tools.</p>
%%
%% @see error_marker_info/1
%% @see warning_marker/1
%% @see eof_marker/0
%% @see is_form/1
%% type(Node) = error_marker
%% data(Node) = term()
%%
%% `erl_parse' representation:
%%
%% {error, Error}
%%
%% Error = term()
%%
%% Note that there is no position information for the node
%% itself: `get_pos' and `set_pos' handle this as a special case.
error_marker(Error) ->
tree(error_marker, Error).
revert_error_marker(Node) ->
%% Note that the position information of the node itself is not
%% preserved.
{error, error_marker_info(Node)}.
%% =====================================================================
%% @spec error_marker_info(syntaxTree()) -> term()
%%
%% @doc Returns the ErrorInfo structure of an <code>error_marker</code>
%% node.
%%
%% @see error_marker/1
error_marker_info(Node) ->
case unwrap(Node) of
{error, Error} ->
Error;
T ->
data(T)
end.
%% =====================================================================
%% @spec warning_marker(Error::term()) -> syntaxTree()
%%
%% @doc Creates an abstract warning marker. The result represents an
%% occurrence of a possible problem in the source code, with an
%% associated Erlang I/O ErrorInfo structure given by <code>Error</code>
%% (see module {@link //stdlib/io} for details). Warning markers are
%% regarded as source code forms, but have no defined lexical form.
%%
%% <p>Note: this is supported only for backwards compatibility with
%% existing parsers and tools.</p>
%%
%% @see warning_marker_info/1
%% @see error_marker/1
%% @see eof_marker/0
%% @see is_form/1
%% type(Node) = warning_marker
%% data(Node) = term()
%%
%% `erl_parse' representation:
%%
%% {warning, Error}
%%
%% Error = term()
%%
%% Note that there is no position information for the node
%% itself: `get_pos' and `set_pos' handle this as a special case.
warning_marker(Warning) ->
tree(warning_marker, Warning).
revert_warning_marker(Node) ->
%% Note that the position information of the node itself is not
%% preserved.
{warning, warning_marker_info(Node)}.
%% =====================================================================
%% @spec warning_marker_info(syntaxTree()) -> term()
%%
%% @doc Returns the ErrorInfo structure of a <code>warning_marker</code>
%% node.
%%
%% @see warning_marker/1
warning_marker_info(Node) ->
case unwrap(Node) of
{warning, Error} ->
Error;
T ->
data(T)
end.
%% =====================================================================
%% @spec eof_marker() -> syntaxTree()
%%
%% @doc Creates an abstract end-of-file marker. This represents the
%% end of input when reading a sequence of source code forms. An
%% end-of-file marker is itself regarded as a source code form
%% (namely, the last in any sequence in which it occurs). It has no
%% defined lexical form.
%%
%% <p>Note: this is retained only for backwards compatibility with
%% existing parsers and tools.</p>
%%
%% @see error_marker/1
%% @see warning_marker/1
%% @see is_form/1
%% type(Node) = eof_marker
%% data(Node) = term()
%%
%% `erl_parse' representation:
%%
%% {eof, Pos}
eof_marker() ->
tree(eof_marker).
revert_eof_marker(Node) ->
Pos = get_pos(Node),
{eof, Pos}.
%% =====================================================================
%% @spec attribute(Name) -> syntaxTree()
%% @equiv attribute(Name, none)
attribute(Name) ->
attribute(Name, none).
%% =====================================================================
%% @spec attribute(Name::syntaxTree(), Arguments) -> syntaxTree()
%% Arguments = none | [syntaxTree()]
%%
%% @doc Creates an abstract program attribute. If
%% <code>Arguments</code> is <code>[A1, ..., An]</code>, the result
%% represents "<code>-<em>Name</em>(<em>A1</em>, ...,
%% <em>An</em>).</code>". Otherwise, if <code>Arguments</code> is
%% <code>none</code>, the result represents
%% "<code>-<em>Name</em>.</code>". The latter form makes it possible
%% to represent preprocessor directives such as
%% "<code>-endif.</code>". Attributes are source code forms.
%%
%% <p>Note: The preprocessor macro definition directive
%% "<code>-define(<em>Name</em>, <em>Body</em>).</code>" has relatively
%% few requirements on the syntactical form of <code>Body</code> (viewed
%% as a sequence of tokens). The <code>text</code> node type can be used
%% for a <code>Body</code> that is not a normal Erlang construct.</p>
%%
%% @see attribute/1
%% @see attribute_name/1
%% @see attribute_arguments/1
%% @see text/1
%% @see is_form/1
-record(attribute, {name, args}).
%% type(Node) = attribute
%% data(Node) = #attribute{name :: Name, args :: Arguments}
%%
%% Name = syntaxTree()
%% Arguments = none | [syntaxTree()]
%%
%% `erl_parse' representation:
%%
%% {attribute, Pos, module, {Name,Vars}}
%% {attribute, Pos, module, Name}
%%
%% Name = atom() | [atom()]
%% Vars = [atom()]
%%
%% Representing `-module(M).', or `-module(M, Vs).', where M is
%% `A1.A2.....An' if Name is `[A1, A2, ..., An]', and Vs is `[V1,
%% ..., Vm]' if Vars is `[V1, ..., Vm]'.
%%
%% {attribute, Pos, export, Exports}
%%
%% Exports = [{atom(), integer()}]
%%
%% Representing `-export([A1/N1, ..., Ak/Nk]).', if `Exports' is
%% `[{A1, N1}, ..., {Ak, Nk}]'.
%%
%% {attribute, Pos, import, Imports}
%%
%% Imports = {atom(), Pairs} | [atom()]
%% Pairs = [{atom(), integer()]
%%
%% Representing `-import(Module, [A1/N1, ..., Ak/Nk]).', if
%% `Imports' is `{Module, [{A1, N1}, ..., {Ak, Nk}]}', or
%% `-import(A1.....An).', if `Imports' is `[A1, ..., An]'.
%%
%% {attribute, Pos, file, Position}
%%
%% Position = {filename(), integer()}
%%
%% Representing `-file(Name, Line).', if `Position' is `{Name,
%% Line}'.
%%
%% {attribute, Pos, record, Info}
%%
%% Info = {Name, [Entries]}
%% Name = atom()
%% Entries = {record_field, Pos, atom()}
%% | {record_field, Pos, atom(), erl_parse()}
%%
%% Representing `-record(Name, {<F1>, ..., <Fn>}).', if `Info' is
%% `{Name, [D1, ..., D1]}', where each `Fi' is either `Ai = <Ei>',
%% if the corresponding `Di' is `{record_field, Pos, Ai, Ei}', or
%% otherwise simply `Ai', if `Di' is `{record_field, Pos, Ai}'.
%%
%% {attribute, L, Name, Term}
%%
%% Name = atom() \ StandardName
%% StandardName = module | export | import | file | record
%% Term = term()
%%
%% Representing `-Name(Term).'.
attribute(Name, Args) ->
tree(attribute, #attribute{name = Name, args = Args}).
revert_attribute(Node) ->
Name = attribute_name(Node),
Args = attribute_arguments(Node),
Pos = get_pos(Node),
case type(Name) of
atom ->
revert_attribute_1(atom_value(Name), Args, Pos, Node);
_ ->
Node
end.
%% All the checking makes this part a bit messy:
revert_attribute_1(module, [M], Pos, Node) ->
case revert_module_name(M) of
{ok, A} ->
{attribute, Pos, module, A};
error -> Node
end;
revert_attribute_1(module, [M, List], Pos, Node) ->
Vs = case is_list_skeleton(List) of
true ->
case is_proper_list(List) of
true ->
fold_variable_names(list_elements(List));
false ->
Node
end;
false ->
Node
end,
case revert_module_name(M) of
{ok, A} ->
{attribute, Pos, module, {A, Vs}};
error -> Node
end;
revert_attribute_1(export, [List], Pos, Node) ->
case is_list_skeleton(List) of
true ->
case is_proper_list(List) of
true ->
Fs = fold_function_names(list_elements(List)),
{attribute, Pos, export, Fs};
false ->
Node
end;
false ->
Node
end;
revert_attribute_1(import, [M], Pos, Node) ->
case revert_module_name(M) of
{ok, A} -> {attribute, Pos, import, A};
error -> Node
end;
revert_attribute_1(import, [M, List], Pos, Node) ->
case revert_module_name(M) of
{ok, A} ->
case is_list_skeleton(List) of
true ->
case is_proper_list(List) of
true ->
Fs = fold_function_names(
list_elements(List)),
{attribute, Pos, import, {A, Fs}};
false ->
Node
end;
false ->
Node
end;
error ->
Node
end;
revert_attribute_1(file, [A, Line], Pos, Node) ->
case type(A) of
string ->
case type(Line) of
integer ->
{attribute, Pos, file,
{concrete(A), concrete(Line)}};
_ ->
Node
end;
_ ->
Node
end;
revert_attribute_1(record, [A, Tuple], Pos, Node) ->
case type(A) of
atom ->
case type(Tuple) of
tuple ->
Fs = fold_record_fields(
tuple_elements(Tuple)),
{attribute, Pos, record, {concrete(A), Fs}};
_ ->
Node
end;
_ ->
Node
end;
revert_attribute_1(N, [T], Pos, _) ->
{attribute, Pos, N, concrete(T)};
revert_attribute_1(_, _, _, Node) ->
Node.
revert_module_name(A) ->
case type(A) of
atom ->
{ok, concrete(A)};
qualified_name ->
Ss = qualified_name_segments(A),
{ok, [concrete(S) || S <- Ss]};
_ ->
error
end.
%% =====================================================================
%% @spec attribute_name(syntaxTree()) -> syntaxTree()
%%
%% @doc Returns the name subtree of an <code>attribute</code> node.
%%
%% @see attribute/1
attribute_name(Node) ->
case unwrap(Node) of
{attribute, Pos, Name, _} ->
set_pos(atom(Name), Pos);
Node1 ->
(data(Node1))#attribute.name
end.
%% =====================================================================
%% @spec attribute_arguments(Node::syntaxTree()) ->
%% none | [syntaxTree()]
%%
%% @doc Returns the list of argument subtrees of an
%% <code>attribute</code> node, if any. If <code>Node</code>
%% represents "<code>-<em>Name</em>.</code>", the result is
%% <code>none</code>. Otherwise, if <code>Node</code> represents
%% "<code>-<em>Name</em>(<em>E1</em>, ..., <em>En</em>).</code>",
%% <code>[E1, ..., E1]</code> is returned.
%%
%% @see attribute/1
attribute_arguments(Node) ->
case unwrap(Node) of
{attribute, Pos, Name, Data} ->
case Name of
module ->
{M1, Vs} =
case Data of
{M0, Vs0} ->
{M0, unfold_variable_names(Vs0, Pos)};
M0 ->
{M0, none}
end,
M2 = if is_list(M1) ->
qualified_name([atom(A) || A <- M1]);
true ->
atom(M1)
end,
M = set_pos(M2, Pos),
if Vs == none -> [M];
true -> [M, set_pos(list(Vs), Pos)]
end;
export ->
[set_pos(
list(unfold_function_names(Data, Pos)),
Pos)];
import ->
case Data of
{Module, Imports} ->
[if is_list(Module) ->
qualified_name([atom(A)
|| A <- Module]);
true ->
set_pos(atom(Module), Pos)
end,
set_pos(
list(unfold_function_names(Imports, Pos)),
Pos)];
_ ->
[qualified_name([atom(A) || A <- Data])]
end;
file ->
{File, Line} = Data,
[set_pos(string(File), Pos),
set_pos(integer(Line), Pos)];
record ->
%% Note that we create a tuple as container
%% for the second argument!
{Type, Entries} = Data,
[set_pos(atom(Type), Pos),
set_pos(tuple(unfold_record_fields(Entries)),
Pos)];
_ ->
%% Standard single-term generic attribute.
[set_pos(abstract(Data), Pos)]
end;
Node1 ->
(data(Node1))#attribute.args
end.
%% =====================================================================
%% @spec arity_qualifier(Body::syntaxTree(), Arity::syntaxTree()) ->
%% syntaxTree()
%%
%% @doc Creates an abstract arity qualifier. The result represents
%% "<code><em>Body</em>/<em>Arity</em></code>".
%%
%% @see arity_qualifier_body/1
%% @see arity_qualifier_argument/1
-record(arity_qualifier, {body, arity}).
%% type(Node) = arity_qualifier
%% data(Node) = #arity_qualifier{body :: Body, arity :: Arity}
%%
%% Body = Arity = syntaxTree()
arity_qualifier(Body, Arity) ->
tree(arity_qualifier,
#arity_qualifier{body = Body, arity = Arity}).
%% =====================================================================
%% @spec arity_qualifier_body(syntaxTree()) -> syntaxTree()
%%
%% @doc Returns the body subtree of an <code>arity_qualifier</code>
%% node.
%%
%% @see arity_qualifier/2
arity_qualifier_body(Node) ->
(data(Node))#arity_qualifier.body.
%% =====================================================================
%% @spec arity_qualifier_argument(syntaxTree()) -> syntaxTree()
%%
%% @doc Returns the argument (the arity) subtree of an
%% <code>arity_qualifier</code> node.
%%
%% @see arity_qualifier/2
arity_qualifier_argument(Node) ->
(data(Node))#arity_qualifier.arity.
%% =====================================================================
%% @spec module_qualifier(Module::syntaxTree(), Body::syntaxTree()) ->
%% syntaxTree()
%%
%% @doc Creates an abstract module qualifier. The result represents
%% "<code><em>Module</em>:<em>Body</em></code>".
%%
%% @see module_qualifier_argument/1
%% @see module_qualifier_body/1
-record(module_qualifier, {module, body}).
%% type(Node) = module_qualifier
%% data(Node) = #module_qualifier{module :: Module, body :: Body}
%%
%% Module = Body = syntaxTree()
%%
%% `erl_parse' representation:
%%
%% {remote, Pos, Module, Arg}
%%
%% Module = Arg = erl_parse()
module_qualifier(Module, Body) ->
tree(module_qualifier,
#module_qualifier{module = Module, body = Body}).
revert_module_qualifier(Node) ->
Pos = get_pos(Node),
Module = module_qualifier_argument(Node),
Body = module_qualifier_body(Node),
{remote, Pos, Module, Body}.
%% =====================================================================
%% @spec module_qualifier_argument(syntaxTree()) -> syntaxTree()
%%
%% @doc Returns the argument (the module) subtree of a
%% <code>module_qualifier</code> node.
%%
%% @see module_qualifier/2
module_qualifier_argument(Node) ->
case unwrap(Node) of
{remote, _, Module, _} ->
Module;
Node1 ->
(data(Node1))#module_qualifier.module
end.
%% =====================================================================
%% @spec module_qualifier_body(syntaxTree()) -> syntaxTree()
%%
%% @doc Returns the body subtree of a <code>module_qualifier</code>
%% node.
%%
%% @see module_qualifier/2
module_qualifier_body(Node) ->
case unwrap(Node) of
{remote, _, _, Body} ->
Body;
Node1 ->
(data(Node1))#module_qualifier.body
end.
%% =====================================================================
%% @spec qualified_name(Segments::[syntaxTree()]) -> syntaxTree()
%%
%% @doc Creates an abstract qualified name. The result represents
%% "<code><em>S1</em>.<em>S2</em>. ... .<em>Sn</em></code>", if
%% <code>Segments</code> is <code>[S1, S2, ..., Sn]</code>.
%%
%% @see qualified_name_segments/1
%% type(Node) = qualified_name
%% data(Node) = [syntaxTree()]
%%
%% `erl_parse' representation:
%%
%% {record_field, Pos, Node, Node}
%%
%% Node = {atom, Pos, Value} | {record_field, Pos, Node, Node}
%%
%% Note that if not all leaf subnodes are (abstract) atoms, then Node
%% represents a Mnemosyne query record field access ('record_access');
%% see type/1 for details.
qualified_name(Segments) ->
tree(qualified_name, Segments).
revert_qualified_name(Node) ->
Pos = get_pos(Node),
fold_qualified_name(qualified_name_segments(Node), Pos).
%% =====================================================================
%% @spec qualified_name_segments(syntaxTree()) -> [syntaxTree()]
%%
%% @doc Returns the list of name segments of a
%% <code>qualified_name</code> node.
%%
%% @see qualified_name/1
qualified_name_segments(Node) ->
case unwrap(Node) of
{record_field, _, _, _} = Node1 ->
unfold_qualified_name(Node1);
Node1 ->
data(Node1)
end.
%% =====================================================================
%% @spec function(Name::syntaxTree(), Clauses::[syntaxTree()]) ->
%% syntaxTree()
%%
%% @doc Creates an abstract function definition. If <code>Clauses</code>
%% is <code>[C1, ..., Cn]</code>, the result represents
%% "<code><em>Name</em> <em>C1</em>; ...; <em>Name</em>
%% <em>Cn</em>.</code>". More exactly, if each <code>Ci</code>
%% represents "<code>(<em>Pi1</em>, ..., <em>Pim</em>) <em>Gi</em> ->
%% <em>Bi</em></code>", then the result represents
%% "<code><em>Name</em>(<em>P11</em>, ..., <em>P1m</em>) <em>G1</em> ->
%% <em>B1</em>; ...; <em>Name</em>(<em>Pn1</em>, ..., <em>Pnm</em>)
%% <em>Gn</em> -> <em>Bn</em>.</code>". Function definitions are source
%% code forms.
%%
%% @see function_name/1
%% @see function_clauses/1
%% @see function_arity/1
%% @see is_form/1
%% @see rule/2
-record(function, {name, clauses}).
%% type(Node) = function
%% data(Node) = #function{name :: Name, clauses :: Clauses}
%%
%% Name = syntaxTree()
%% Clauses = [syntaxTree()]
%%
%% (There's no real point in precomputing and storing the arity,
%% and passing it as a constructor argument makes it possible to
%% end up with an inconsistent value. Besides, some people might
%% want to check all clauses, and not just the first, so the
%% computation is not obvious.)
%%
%% `erl_parse' representation:
%%
%% {function, Pos, Name, Arity, Clauses}
%%
%% Name = atom()
%% Arity = integer()
%% Clauses = [Clause] \ []
%% Clause = {clause, ...}
%%
%% where the number of patterns in each clause should be equal to
%% the integer `Arity'; see `clause' for documentation on
%% `erl_parse' clauses.
function(Name, Clauses) ->
tree(function, #function{name = Name, clauses = Clauses}).
revert_function(Node) ->
Name = function_name(Node),
Clauses = [revert_clause(C) || C <- function_clauses(Node)],
Pos = get_pos(Node),
case type(Name) of
atom ->
A = function_arity(Node),
{function, Pos, concrete(Name), A, Clauses};
_ ->
Node
end.
%% =====================================================================
%% @spec function_name(syntaxTree()) -> syntaxTree()
%%
%% @doc Returns the name subtree of a <code>function</code> node.
%%
%% @see function/2
function_name(Node) ->
case unwrap(Node) of
{function, Pos, Name, _, _} ->
set_pos(atom(Name), Pos);
Node1 ->
(data(Node1))#function.name
end.
%% =====================================================================
%% @spec function_clauses(syntaxTree()) -> [syntaxTree()]
%%
%% @doc Returns the list of clause subtrees of a <code>function</code>
%% node.
%%
%% @see function/2
function_clauses(Node) ->
case unwrap(Node) of
{function, _, _, _, Clauses} ->
Clauses;
Node1 ->
(data(Node1))#function.clauses
end.
%% =====================================================================
%% @spec function_arity(Node::syntaxTree()) -> integer()
%%
%% @doc Returns the arity of a <code>function</code> node. The result
%% is the number of parameter patterns in the first clause of the
%% function; subsequent clauses are ignored.
%%
%% <p>An exception is thrown if <code>function_clauses(Node)</code>
%% returns an empty list, or if the first element of that list is not
%% a syntax tree <code>C</code> of type <code>clause</code> such that
%% <code>clause_patterns(C)</code> is a nonempty list.</p>
%%
%% @see function/2
%% @see function_clauses/1
%% @see clause/3
%% @see clause_patterns/1
function_arity(Node) ->
%% Note that this never accesses the arity field of `erl_parse'
%% function nodes.
length(clause_patterns(hd(function_clauses(Node)))).
%% =====================================================================
%% @spec clause(Guard, Body) -> syntaxTree()
%% @equiv clause([], Guard, Body)
clause(Guard, Body) ->
clause([], Guard, Body).
%% =====================================================================
%% @spec clause(Patterns::[syntaxTree()], Guard,
%% Body::[syntaxTree()]) -> syntaxTree()
%% Guard = none | syntaxTree()
%% | [syntaxTree()] | [[syntaxTree()]]
%%
%% @doc Creates an abstract clause. If <code>Patterns</code> is
%% <code>[P1, ..., Pn]</code> and <code>Body</code> is <code>[B1, ...,
%% Bm]</code>, then if <code>Guard</code> is <code>none</code>, the
%% result represents "<code>(<em>P1</em>, ..., <em>Pn</em>) ->
%% <em>B1</em>, ..., <em>Bm</em></code>", otherwise, unless
%% <code>Guard</code> is a list, the result represents
%% "<code>(<em>P1</em>, ..., <em>Pn</em>) when <em>Guard</em> ->
%% <em>B1</em>, ..., <em>Bm</em></code>".
%%
%% <p>For simplicity, the <code>Guard</code> argument may also be any
%% of the following:
%% <ul>
%% <li>An empty list <code>[]</code>. This is equivalent to passing
%% <code>none</code>.</li>
%% <li>A nonempty list <code>[E1, ..., Ej]</code> of syntax trees.
%% This is equivalent to passing <code>conjunction([E1, ...,
%% Ej])</code>.</li>
%% <li>A nonempty list of lists of syntax trees <code>[[E1_1, ...,
%% E1_k1], ..., [Ej_1, ..., Ej_kj]]</code>, which is equivalent
%% to passing <code>disjunction([conjunction([E1_1, ...,
%% E1_k1]), ..., conjunction([Ej_1, ..., Ej_kj])])</code>.</li>
%% </ul>
%% </p>
%%
%% @see clause/2
%% @see clause_patterns/1
%% @see clause_guard/1
%% @see clause_body/1
-record(clause, {patterns, guard, body}).
%% type(Node) = clause
%% data(Node) = #clause{patterns :: Patterns, guard :: Guard,
%% body :: Body}
%%
%% Patterns = [syntaxTree()]
%% Guard = syntaxTree() | none
%% Body = [syntaxTree()]
%%
%% `erl_parse' representation:
%%
%% {clause, Pos, Patterns, Guard, Body}
%%
%% Patterns = [erl_parse()]
%% Guard = [[erl_parse()]] | [erl_parse()]
%% Body = [erl_parse()] \ []
%%
%% Taken out of context, if `Patterns' is `[P1, ..., Pn]' and
%% `Body' is `[B1, ..., Bm]', this represents `(<P1>, ..., <Pn>) ->
%% <B1>, ..., <Bm>' if `Guard' is `[]', or otherwise `(<P1>, ...,
%% <Pn>) when <G> -> <Body>', where `G' is `<E1_1>, ..., <E1_k1>;
%% ...; <Ej_1>, ..., <Ej_kj>', if `Guard' is a list of lists
%% `[[E1_1, ..., E1_k1], ..., [Ej_1, ..., Ej_kj]]'. In older
%% versions, `Guard' was simply a list `[E1, ..., En]' of parse
%% trees, which is equivalent to the new form `[[E1, ..., En]]'.
clause(Patterns, Guard, Body) ->
Guard1 = case Guard of
[] ->
none;
[X | _] when is_list(X) ->
disjunction(conjunction_list(Guard));
[_ | _] ->
%% Handle older forms also.
conjunction(Guard);
_ ->
%% This should be `none' or a syntax tree.
Guard
end,
tree(clause, #clause{patterns = Patterns, guard = Guard1,
body = Body}).
conjunction_list([L | Ls]) ->
[conjunction(L) | conjunction_list(Ls)];
conjunction_list([]) ->
[].
revert_clause(Node) ->
Pos = get_pos(Node),
Guard = case clause_guard(Node) of
none ->
[];
E ->
case type(E) of
disjunction ->
revert_clause_disjunction(E);
conjunction ->
%% Only the top level expression is
%% unfolded here; no recursion.
[conjunction_body(E)];
_ ->
[[E]] % a single expression
end
end,
{clause, Pos, clause_patterns(Node), Guard,
clause_body(Node)}.
revert_clause_disjunction(D) ->
%% We handle conjunctions within a disjunction, but only at
%% the top level; no recursion.
[case type(E) of
conjunction ->
conjunction_body(E);
_ ->
[E]
end
|| E <- disjunction_body(D)].
revert_try_clause(Node) ->
fold_try_clause(revert_clause(Node)).
fold_try_clause({clause, Pos, [P], Guard, Body}) ->
P1 = case type(P) of
class_qualifier ->
{tuple, Pos, [class_qualifier_argument(P),
class_qualifier_body(P),
{var, Pos, '_'}]};
_ ->
{tuple, Pos, [{atom, Pos, throw}, P, {var, Pos, '_'}]}
end,
{clause, Pos, [P1], Guard, Body}.
unfold_try_clauses(Cs) ->
[unfold_try_clause(C) || C <- Cs].
unfold_try_clause({clause, Pos, [{tuple, _, [{atom,_,throw}, V, _]}],
Guard, Body}) ->
{clause, Pos, [V], Guard, Body};
unfold_try_clause({clause, Pos, [{tuple, _, [C, V, _]}],
Guard, Body}) ->
{clause, Pos, [class_qualifier(C, V)], Guard, Body}.
%% =====================================================================
%% @spec clause_patterns(syntaxTree()) -> [syntaxTree()]
%%
%% @doc Returns the list of pattern subtrees of a <code>clause</code>
%% node.
%%
%% @see clause/3
clause_patterns(Node) ->
case unwrap(Node) of
{clause, _, Patterns, _, _} ->
Patterns;
Node1 ->
(data(Node1))#clause.patterns
end.
%% =====================================================================
%% @spec clause_guard(Node::syntaxTree()) -> none | syntaxTree()
%%
%% @doc Returns the guard subtree of a <code>clause</code> node, if
%% any. If <code>Node</code> represents "<code>(<em>P1</em>, ...,
%% <em>Pn</em>) when <em>Guard</em> -> <em>B1</em>, ...,
%% <em>Bm</em></code>", <code>Guard</code> is returned. Otherwise, the
%% result is <code>none</code>.
%%
%% @see clause/3
clause_guard(Node) ->
case unwrap(Node) of
{clause, _, _, Guard, _} ->
case Guard of
[] -> none;
[L | _] when is_list(L) ->
disjunction(conjunction_list(Guard));
[_ | _] ->
conjunction(Guard)
end;
Node1 ->
(data(Node1))#clause.guard
end.
%% =====================================================================
%% @spec clause_body(syntaxTree()) -> [syntaxTree()]
%%
%% @doc Return the list of body subtrees of a <code>clause</code>
%% node.
%%
%% @see clause/3
clause_body(Node) ->
case unwrap(Node) of
{clause, _, _, _, Body} ->
Body;
Node1 ->
(data(Node1))#clause.body
end.
%% =====================================================================
%% @spec disjunction(List::[syntaxTree()]) -> syntaxTree()
%%
%% @doc Creates an abstract disjunction. If <code>List</code> is
%% <code>[E1, ..., En]</code>, the result represents
%% "<code><em>E1</em>; ...; <em>En</em></code>".
%%
%% @see disjunction_body/1
%% @see conjunction/1
%% type(Node) = disjunction
%% data(Node) = [syntaxTree()]
disjunction(Tests) ->
tree(disjunction, Tests).
%% =====================================================================
%% @spec disjunction_body(syntaxTree()) -> [syntaxTree()]
%%
%% @doc Returns the list of body subtrees of a
%% <code>disjunction</code> node.
%%
%% @see disjunction/1
disjunction_body(Node) ->
data(Node).
%% =====================================================================
%% @spec conjunction(List::[syntaxTree()]) -> syntaxTree()
%%
%% @doc Creates an abstract conjunction. If <code>List</code> is
%% <code>[E1, ..., En]</code>, the result represents
%% "<code><em>E1</em>, ..., <em>En</em></code>".
%%
%% @see conjunction_body/1
%% @see disjunction/1
%% type(Node) = conjunction
%% data(Node) = [syntaxTree()]
conjunction(Tests) ->
tree(conjunction, Tests).
%% =====================================================================
%% @spec conjunction_body(syntaxTree()) -> [syntaxTree()]
%%
%% @doc Returns the list of body subtrees of a
%% <code>conjunction</code> node.
%%
%% @see conjunction/1
conjunction_body(Node) ->
data(Node).
%% =====================================================================
%% @spec catch_expr(Expr::syntaxTree()) -> syntaxTree()
%%
%% @doc Creates an abstract catch-expression. The result represents
%% "<code>catch <em>Expr</em></code>".
%%
%% @see catch_expr_body/1
%% type(Node) = catch_expr
%% data(Node) = syntaxTree()
%%
%% `erl_parse' representation:
%%
%% {'catch', Pos, Expr}
%%
%% Expr = erl_parse()
catch_expr(Expr) ->
tree(catch_expr, Expr).
revert_catch_expr(Node) ->
Pos = get_pos(Node),
Expr = catch_expr_body(Node),
{'catch', Pos, Expr}.
%% =====================================================================
%% @spec catch_expr_body(syntaxTree()) -> syntaxTree()
%%
%% @doc Returns the body subtree of a <code>catch_expr</code> node.
%%
%% @see catch_expr/1
catch_expr_body(Node) ->
case unwrap(Node) of
{'catch', _, Expr} ->
Expr;
Node1 ->
data(Node1)
end.
%% =====================================================================
%% @spec match_expr(Pattern::syntaxTree(), Body::syntaxTree()) ->
%% syntaxTree()
%%
%% @doc Creates an abstract match-expression. The result represents
%% "<code><em>Pattern</em> = <em>Body</em></code>".
%%
%% @see match_expr_pattern/1
%% @see match_expr_body/1
-record(match_expr, {pattern, body}).
%% type(Node) = match_expr
%% data(Node) = #match_expr{pattern :: Pattern, body :: Body}
%%
%% Pattern = Body = syntaxTree()
%%
%% `erl_parse' representation:
%%
%% {match, Pos, Pattern, Body}
%%
%% Pattern = Body = erl_parse()
match_expr(Pattern, Body) ->
tree(match_expr, #match_expr{pattern = Pattern, body = Body}).
revert_match_expr(Node) ->
Pos = get_pos(Node),
Pattern = match_expr_pattern(Node),
Body = match_expr_body(Node),
{match, Pos, Pattern, Body}.
%% =====================================================================
%% @spec match_expr_pattern(syntaxTree()) -> syntaxTree()
%%
%% @doc Returns the pattern subtree of a <code>match_expr</code> node.
%%
%% @see match_expr/2
match_expr_pattern(Node) ->
case unwrap(Node) of
{match, _, Pattern, _} ->
Pattern;
Node1 ->
(data(Node1))#match_expr.pattern
end.
%% =====================================================================
%% @spec match_expr_body(syntaxTree()) -> syntaxTree()
%%
%% @doc Returns the body subtree of a <code>match_expr</code> node.
%%
%% @see match_expr/2
match_expr_body(Node) ->
case unwrap(Node) of
{match, _, _, Body} ->
Body;
Node1 ->
(data(Node1))#match_expr.body
end.
%% =====================================================================
%% @spec operator(Name) -> syntaxTree()
%% Name = atom() | string()
%%
%% @doc Creates an abstract operator. The name of the operator is the
%% character sequence represented by <code>Name</code>. This is
%% analogous to the print name of an atom, but an operator is never
%% written within single-quotes; e.g., the result of
%% <code>operator('++')</code> represents "<code>++</code>" rather
%% than "<code>'++'</code>".
%%
%% @see operator_name/1
%% @see operator_literal/1
%% @see atom/1
%% type(Node) = operator
%% data(Node) = atom()
operator(Name) when is_atom(Name) ->
tree(operator, Name);
operator(Name) ->
tree(operator, list_to_atom(Name)).
%% =====================================================================
%% @spec operator_name(syntaxTree()) -> atom()
%%
%% @doc Returns the name of an <code>operator</code> node. Note that
%% the name is returned as an atom.
%%
%% @see operator/1
operator_name(Node) ->
data(Node).
%% =====================================================================
%% @spec operator_literal(syntaxTree()) -> string()
%%
%% @doc Returns the literal string represented by an
%% <code>operator</code> node. This is simply the operator name as a
%% string.
%%
%% @see operator/1
operator_literal(Node) ->
atom_to_list(operator_name(Node)).
%% =====================================================================
%% @spec infix_expr(Left::syntaxTree(), Operator::syntaxTree(),
%% Right::syntaxTree()) -> syntaxTree()
%%
%% @doc Creates an abstract infix operator expression. The result
%% represents "<code><em>Left</em> <em>Operator</em>
%% <em>Right</em></code>".
%%
%% @see infix_expr_left/1
%% @see infix_expr_right/1
%% @see infix_expr_operator/1
%% @see prefix_expr/2
-record(infix_expr, {operator, left, right}).
%% type(Node) = infix_expr
%% data(Node) = #infix_expr{left :: Left, operator :: Operator,
%% right :: Right}
%%
%% Left = Operator = Right = syntaxTree()
%%
%% `erl_parse' representation:
%%
%% {op, Pos, Operator, Left, Right}
%%
%% Operator = atom()
%% Left = Right = erl_parse()
infix_expr(Left, Operator, Right) ->
tree(infix_expr, #infix_expr{operator = Operator, left = Left,
right = Right}).
revert_infix_expr(Node) ->
Pos = get_pos(Node),
Operator = infix_expr_operator(Node),
Left = infix_expr_left(Node),
Right = infix_expr_right(Node),
case type(Operator) of
operator ->
%% Note that the operator itself is not revertible out
%% of context.
{op, Pos, operator_name(Operator), Left, Right};
_ ->
Node
end.
%% =====================================================================
%% @spec infix_expr_left(syntaxTree()) -> syntaxTree()
%%
%% @doc Returns the left argument subtree of an
%% <code>infix_expr</code> node.
%%
%% @see infix_expr/3
infix_expr_left(Node) ->
case unwrap(Node) of
{op, _, _, Left, _} ->
Left;
Node1 ->
(data(Node1))#infix_expr.left
end.
%% =====================================================================
%% @spec infix_expr_operator(syntaxTree()) -> syntaxTree()
%%
%% @doc Returns the operator subtree of an <code>infix_expr</code>
%% node.
%%
%% @see infix_expr/3
infix_expr_operator(Node) ->
case unwrap(Node) of
{op, Pos, Operator, _, _} ->
set_pos(operator(Operator), Pos);
Node1 ->
(data(Node1))#infix_expr.operator
end.
%% =====================================================================
%% @spec infix_expr_right(syntaxTree()) -> syntaxTree()
%%
%% @doc Returns the right argument subtree of an
%% <code>infix_expr</code> node.
%%
%% @see infix_expr/3
infix_expr_right(Node) ->
case unwrap(Node) of
{op, _, _, _, Right} ->
Right;
Node1 ->
(data(Node1))#infix_expr.right
end.
%% =====================================================================
%% @spec prefix_expr(Operator::syntaxTree(), Argument::syntaxTree()) ->
%% syntaxTree()
%%
%% @doc Creates an abstract prefix operator expression. The result
%% represents "<code><em>Operator</em> <em>Argument</em></code>".
%%
%% @see prefix_expr_argument/1
%% @see prefix_expr_operator/1
%% @see infix_expr/3
-record(prefix_expr, {operator, argument}).
%% type(Node) = prefix_expr
%% data(Node) = #prefix_expr{operator :: Operator,
%% argument :: Argument}
%%
%% Operator = Argument = syntaxTree()
%%
%% `erl_parse' representation:
%%
%% {op, Pos, Operator, Arg}
%%
%% Operator = atom()
%% Argument = erl_parse()
prefix_expr(Operator, Argument) ->
tree(prefix_expr, #prefix_expr{operator = Operator,
argument = Argument}).
revert_prefix_expr(Node) ->
Pos = get_pos(Node),
Operator = prefix_expr_operator(Node),
Argument = prefix_expr_argument(Node),
case type(Operator) of
operator ->
%% Note that the operator itself is not revertible out
%% of context.
{op, Pos, operator_name(Operator), Argument};
_ ->
Node
end.
%% =====================================================================
%% @spec prefix_expr_operator(syntaxTree()) -> syntaxTree()
%%
%% @doc Returns the operator subtree of a <code>prefix_expr</code>
%% node.
%%
%% @see prefix_expr/2
prefix_expr_operator(Node) ->
case unwrap(Node) of
{op, Pos, Operator, _} ->
set_pos(operator(Operator), Pos);
Node1 ->
(data(Node1))#prefix_expr.operator
end.
%% =====================================================================
%% @spec prefix_expr_argument(syntaxTree()) -> syntaxTree()
%%
%% @doc Returns the argument subtree of a <code>prefix_expr</code>
%% node.
%%
%% @see prefix_expr/2
prefix_expr_argument(Node) ->
case unwrap(Node) of
{op, _, _, Argument} ->
Argument;
Node1 ->
(data(Node1))#prefix_expr.argument
end.
%% =====================================================================
%% @spec record_field(Name) -> syntaxTree()
%% @equiv record_field(Name, none)
record_field(Name) ->
record_field(Name, none).
%% =====================================================================
%% @spec record_field(Name::syntaxTree(), Value) -> syntaxTree()
%% Value = none | syntaxTree()
%%
%% @doc Creates an abstract record field specification. If
%% <code>Value</code> is <code>none</code>, the result represents
%% simply "<code><em>Name</em></code>", otherwise it represents
%% "<code><em>Name</em> = <em>Value</em></code>".
%%
%% @see record_field_name/1
%% @see record_field_value/1
%% @see record_expr/3
-record(record_field, {name, value}).
%% type(Node) = record_field
%% data(Node) = #record_field{name :: Name, value :: Value}
%%
%% Name = Value = syntaxTree()
record_field(Name, Value) ->
tree(record_field, #record_field{name = Name, value = Value}).
%% =====================================================================
%% @spec record_field_name(syntaxTree()) -> syntaxTree()
%%
%% @doc Returns the name subtree of a <code>record_field</code> node.
%%
%% @see record_field/2
record_field_name(Node) ->
(data(Node))#record_field.name.
%% =====================================================================
%% @spec record_field_value(syntaxTree()) -> none | syntaxTree()
%%
%% @doc Returns the value subtree of a <code>record_field</code> node,
%% if any. If <code>Node</code> represents
%% "<code><em>Name</em></code>", <code>none</code> is
%% returned. Otherwise, if <code>Node</code> represents
%% "<code><em>Name</em> = <em>Value</em></code>", <code>Value</code>
%% is returned.
%%
%% @see record_field/2
record_field_value(Node) ->
(data(Node))#record_field.value.
%% =====================================================================
%% @spec record_index_expr(Type::syntaxTree(), Field::syntaxTree()) ->
%% syntaxTree()
%%
%% @doc Creates an abstract record field index expression. The result
%% represents "<code>#<em>Type</em>.<em>Field</em></code>".
%%
%% <p>(Note: the function name <code>record_index/2</code> is reserved
%% by the Erlang compiler, which is why that name could not be used
%% for this constructor.)</p>
%%
%% @see record_index_expr_type/1
%% @see record_index_expr_field/1
%% @see record_expr/3
-record(record_index_expr, {type, field}).
%% type(Node) = record_index_expr
%% data(Node) = #record_index_expr{type :: Type, field :: Field}
%%
%% Type = Field = syntaxTree()
%%
%% `erl_parse' representation:
%%
%% {record_index, Pos, Type, Field}
%%
%% Type = atom()
%% Field = erl_parse()
record_index_expr(Type, Field) ->
tree(record_index_expr, #record_index_expr{type = Type,
field = Field}).
revert_record_index_expr(Node) ->
Pos = get_pos(Node),
Type = record_index_expr_type(Node),
Field = record_index_expr_field(Node),
case type(Type) of
atom ->
{record_index, Pos, concrete(Type), Field};
_ ->
Node
end.
%% =====================================================================
%% @spec record_index_expr_type(syntaxTree()) -> syntaxTree()
%%
%% @doc Returns the type subtree of a <code>record_index_expr</code>
%% node.
%%
%% @see record_index_expr/2
record_index_expr_type(Node) ->
case unwrap(Node) of
{record_index, Pos, Type, _} ->
set_pos(atom(Type), Pos);
Node1 ->
(data(Node1))#record_index_expr.type
end.
%% =====================================================================
%% @spec record_index_expr_field(syntaxTree()) -> syntaxTree()
%%
%% @doc Returns the field subtree of a <code>record_index_expr</code>
%% node.
%%
%% @see record_index_expr/2
record_index_expr_field(Node) ->
case unwrap(Node) of
{record_index, _, _, Field} ->
Field;
Node1 ->
(data(Node1))#record_index_expr.field
end.
%% =====================================================================
%% @spec record_access(Argument, Field) -> syntaxTree()
%% @equiv record_access(Argument, none, Field)
record_access(Argument, Field) ->
record_access(Argument, none, Field).
%% =====================================================================
%% @spec record_access(Argument::syntaxTree(), Type,
%% Field::syntaxTree()) -> syntaxTree()
%% Type = none | syntaxTree()
%%
%% @doc Creates an abstract record field access expression. If
%% <code>Type</code> is not <code>none</code>, the result represents
%% "<code><em>Argument</em>#<em>Type</em>.<em>Field</em></code>".
%%
%% <p>If <code>Type</code> is <code>none</code>, the result represents
%% "<code><em>Argument</em>.<em>Field</em></code>". This is a special
%% form only allowed within Mnemosyne queries.</p>
%%
%% @see record_access/2
%% @see record_access_argument/1
%% @see record_access_type/1
%% @see record_access_field/1
%% @see record_expr/3
%% @see query_expr/1
-record(record_access, {argument, type, field}).
%% type(Node) = record_access
%% data(Node) = #record_access{argument :: Argument, type :: Type,
%% field :: Field}
%%
%% Argument = Field = syntaxTree()
%% Type = none | syntaxTree()
%%
%% `erl_parse' representation:
%%
%% {record_field, Pos, Argument, Type, Field}
%% {record_field, Pos, Argument, Field}
%%
%% Argument = Field = erl_parse()
%% Type = atom()
record_access(Argument, Type, Field) ->
tree(record_access,#record_access{argument = Argument,
type = Type,
field = Field}).
revert_record_access(Node) ->
Pos = get_pos(Node),
Argument = record_access_argument(Node),
Type = record_access_type(Node),
Field = record_access_field(Node),
if Type =:= none ->
{record_field, Pos, Argument, Field};
true ->
case type(Type) of
atom ->
{record_field, Pos,
Argument, concrete(Type), Field};
_ ->
Node
end
end.
%% =====================================================================
%% @spec record_access_argument(syntaxTree()) -> syntaxTree()
%%
%% @doc Returns the argument subtree of a <code>record_access</code>
%% node.
%%
%% @see record_access/3
record_access_argument(Node) ->
case unwrap(Node) of
{record_field, _, Argument, _} ->
Argument;
{record_field, _, Argument, _, _} ->
Argument;
Node1 ->
(data(Node1))#record_access.argument
end.
%% =====================================================================
%% @spec record_access_type(syntaxTree()) -> none | syntaxTree()
%%
%% @doc Returns the type subtree of a <code>record_access</code> node,
%% if any. If <code>Node</code> represents
%% "<code><em>Argument</em>.<em>Field</em></code>", <code>none</code>
%% is returned, otherwise if <code>Node</code> represents
%% "<code><em>Argument</em>#<em>Type</em>.<em>Field</em></code>",
%% <code>Type</code> is returned.
%%
%% @see record_access/3
record_access_type(Node) ->
case unwrap(Node) of
{record_field, _, _, _} ->
none;
{record_field, Pos, _, Type, _} ->
set_pos(atom(Type), Pos);
Node1 ->
(data(Node1))#record_access.type
end.
%% =====================================================================
%% @spec record_access_field(syntaxTree()) -> syntaxTree()
%%
%% @doc Returns the field subtree of a <code>record_access</code>
%% node.
%%
%% @see record_access/3
record_access_field(Node) ->
case unwrap(Node) of
{record_field, _, _, Field} ->
Field;
{record_field, _, _, _, Field} ->
Field;
Node1 ->
(data(Node1))#record_access.field
end.
%% =====================================================================
%% @spec record_expr(Type, Fields) -> syntaxTree()
%% @equiv record_expr(none, Type, Fields)
record_expr(Type, Fields) ->
record_expr(none, Type, Fields).
%% =====================================================================
%% @spec record_expr(Argument, Type::syntaxTree(),
%% Fields::[syntaxTree()]) -> syntaxTree()
%% Argument = none | syntaxTree()
%%
%% @doc Creates an abstract record expression. If <code>Fields</code> is
%% <code>[F1, ..., Fn]</code>, then if <code>Argument</code> is
%% <code>none</code>, the result represents
%% "<code>#<em>Type</em>{<em>F1</em>, ..., <em>Fn</em>}</code>",
%% otherwise it represents
%% "<code><em>Argument</em>#<em>Type</em>{<em>F1</em>, ...,
%% <em>Fn</em>}</code>".
%%
%% @see record_expr/2
%% @see record_expr_argument/1
%% @see record_expr_fields/1
%% @see record_expr_type/1
%% @see record_field/2
%% @see record_index_expr/2
%% @see record_access/3
-record(record_expr, {argument, type, fields}).
%% type(Node) = record_expr
%% data(Node) = #record_expr{argument :: Argument, type :: Type,
%% fields :: Fields}
%%
%% Argument = none | syntaxTree()
%% Type = syntaxTree
%% Fields = [syntaxTree()]
%%
%% `erl_parse' representation:
%%
%% {record, Pos, Type, Fields}
%% {record, Pos, Argument, Type, Fields}
%%
%% Argument = erl_parse()
%% Type = atom()
%% Fields = [Entry]
%% Entry = {record_field, Pos, Field, Value}
%% | {record_field, Pos, Field}
%% Field = Value = erl_parse()
record_expr(Argument, Type, Fields) ->
tree(record_expr, #record_expr{argument = Argument,
type = Type, fields = Fields}).
revert_record_expr(Node) ->
Pos = get_pos(Node),
Argument = record_expr_argument(Node),
Type = record_expr_type(Node),
Fields = record_expr_fields(Node),
case type(Type) of
atom ->
T = concrete(Type),
Fs = fold_record_fields(Fields),
case Argument of
none ->
{record, Pos, T, Fs};
_ ->
{record, Pos, Argument, T, Fs}
end;
_ ->
Node
end.
%% =====================================================================
%% @spec record_expr_argument(syntaxTree()) -> none | syntaxTree()
%%
%% @doc Returns the argument subtree of a <code>record_expr</code> node,
%% if any. If <code>Node</code> represents
%% "<code>#<em>Type</em>{...}</code>", <code>none</code> is returned.
%% Otherwise, if <code>Node</code> represents
%% "<code><em>Argument</em>#<em>Type</em>{...}</code>",
%% <code>Argument</code> is returned.
%%
%% @see record_expr/3
record_expr_argument(Node) ->
case unwrap(Node) of
{record, _, _, _} ->
none;
{record, _, Argument, _, _} ->
Argument;
Node1 ->
(data(Node1))#record_expr.argument
end.
%% =====================================================================
%% @spec record_expr_type(syntaxTree()) -> syntaxTree()
%%
%% @doc Returns the type subtree of a <code>record_expr</code> node.
%%
%% @see record_expr/3
record_expr_type(Node) ->
case unwrap(Node) of
{record, Pos, Type, _} ->
set_pos(atom(Type), Pos);
{record, Pos, _, Type, _} ->
set_pos(atom(Type), Pos);
Node1 ->
(data(Node1))#record_expr.type
end.
%% =====================================================================
%% @spec record_expr_fields(syntaxTree()) -> [syntaxTree()]
%%
%% @doc Returns the list of field subtrees of a
%% <code>record_expr</code> node.
%%
%% @see record_expr/3
record_expr_fields(Node) ->
case unwrap(Node) of
{record, _, _, Fields} ->
unfold_record_fields(Fields);
{record, _, _, _, Fields} ->
unfold_record_fields(Fields);
Node1 ->
(data(Node1))#record_expr.fields
end.
%% =====================================================================
%% @spec application(Module, Function::syntaxTree(),
%% Arguments::[syntaxTree()]) -> syntaxTree()
%% Module = none | syntaxTree()
%%
%% @doc Creates an abstract function application expression. If
%% <code>Module</code> is <code>none</code>, this is call is equivalent
%% to <code>application(Function, Arguments)</code>, otherwise it is
%% equivalent to <code>application(module_qualifier(Module, Function),
%% Arguments)</code>.
%%
%% (This is a utility function.)
%%
%% @see application/2
%% @see module_qualifier/2
application(none, Name, Arguments) ->
application(Name, Arguments);
application(Module, Name, Arguments) ->
application(module_qualifier(Module, Name), Arguments).
%% =====================================================================
%% @spec application(Operator::syntaxTree(),
%% Arguments::[syntaxTree()]) -> syntaxTree()
%%
%% @doc Creates an abstract function application expression. If
%% <code>Arguments</code> is <code>[A1, ..., An]</code>, the result
%% represents "<code><em>Operator</em>(<em>A1</em>, ...,
%% <em>An</em>)</code>".
%%
%% @see application_operator/1
%% @see application_arguments/1
%% @see application/3
-record(application, {operator, arguments}).
%% type(Node) = application
%% data(Node) = #application{operator :: Operator,
%% arguments :: Arguments}
%%
%% Operator = syntaxTree()
%% Arguments = [syntaxTree()]
%%
%% `erl_parse' representation:
%%
%% {call, Pos, Fun, Args}
%%
%% Operator = erl_parse()
%% Arguments = [erl_parse()]
application(Operator, Arguments) ->
tree(application, #application{operator = Operator,
arguments = Arguments}).
revert_application(Node) ->
Pos = get_pos(Node),
Operator = application_operator(Node),
Arguments = application_arguments(Node),
{call, Pos, Operator, Arguments}.
%% =====================================================================
%% @spec application_operator(syntaxTree()) -> syntaxTree()
%%
%% @doc Returns the operator subtree of an <code>application</code>
%% node.
%%
%% <p>Note: if <code>Node</code> represents
%% "<code><em>M</em>:<em>F</em>(...)</code>", then the result is the
%% subtree representing "<code><em>M</em>:<em>F</em></code>".</p>
%%
%% @see application/2
%% @see module_qualifier/2
application_operator(Node) ->
case unwrap(Node) of
{call, _, Operator, _} ->
Operator;
Node1 ->
(data(Node1))#application.operator
end.
%% =====================================================================
%% @spec application_arguments(syntaxTree()) -> [syntaxTree()]
%%
%% @doc Returns the list of argument subtrees of an
%% <code>application</code> node.
%%
%% @see application/2
application_arguments(Node) ->
case unwrap(Node) of
{call, _, _, Arguments} ->
Arguments;
Node1 ->
(data(Node1))#application.arguments
end.
%% =====================================================================
%% @spec list_comp(Template::syntaxTree(), Body::[syntaxTree()]) ->
%% syntaxTree()
%%
%% @doc Creates an abstract list comprehension. If <code>Body</code> is
%% <code>[E1, ..., En]</code>, the result represents
%% "<code>[<em>Template</em> || <em>E1</em>, ..., <em>En</em>]</code>".
%%
%% @see list_comp_template/1
%% @see list_comp_body/1
%% @see generator/2
-record(list_comp, {template, body}).
%% type(Node) = list_comp
%% data(Node) = #list_comp{template :: Template, body :: Body}
%%
%% Template = Node = syntaxTree()
%% Body = [syntaxTree()]
%%
%% `erl_parse' representation:
%%
%% {lc, Pos, Template, Body}
%%
%% Template = erl_parse()
%% Body = [erl_parse()] \ []
list_comp(Template, Body) ->
tree(list_comp, #list_comp{template = Template, body = Body}).
revert_list_comp(Node) ->
Pos = get_pos(Node),
Template = list_comp_template(Node),
Body = list_comp_body(Node),
{lc, Pos, Template, Body}.
%% =====================================================================
%% @spec list_comp_template(syntaxTree()) -> syntaxTree()
%%
%% @doc Returns the template subtree of a <code>list_comp</code> node.
%%
%% @see list_comp/2
list_comp_template(Node) ->
case unwrap(Node) of
{lc, _, Template, _} ->
Template;
Node1 ->
(data(Node1))#list_comp.template
end.
%% =====================================================================
%% @spec list_comp_body(syntaxTree()) -> [syntaxTree()]
%%
%% @doc Returns the list of body subtrees of a <code>list_comp</code>
%% node.
%%
%% @see list_comp/2
list_comp_body(Node) ->
case unwrap(Node) of
{lc, _, _, Body} ->
Body;
Node1 ->
(data(Node1))#list_comp.body
end.
%% =====================================================================
%% @spec binary_comp(Template::syntaxTree(), Body::[syntaxTree()]) ->
%% syntaxTree()
%%
%% @doc Creates an abstract binary comprehension. If <code>Body</code> is
%% <code>[E1, ..., En]</code>, the result represents
%% "<code><<<em>Template</em> || <em>E1</em>, ..., <em>En</em>>></code>".
%%
%% @see binary_comp_template/1
%% @see binary_comp_body/1
%% @see generator/2
-record(binary_comp, {template, body}).
%% type(Node) = binary_comp
%% data(Node) = #binary_comp{template :: Template, body :: Body}
%%
%% Template = Node = syntaxTree()
%% Body = [syntaxTree()]
%%
%% `erl_parse' representation:
%%
%% {bc, Pos, Template, Body}
%%
%% Template = erl_parse()
%% Body = [erl_parse()] \ []
binary_comp(Template, Body) ->
tree(binary_comp, #binary_comp{template = Template, body = Body}).
revert_binary_comp(Node) ->
Pos = get_pos(Node),
Template = binary_comp_template(Node),
Body = binary_comp_body(Node),
{bc, Pos, Template, Body}.
%% =====================================================================
%% @spec binary_comp_template(syntaxTree()) -> syntaxTree()
%%
%% @doc Returns the template subtree of a <code>binary_comp</code> node.
%%
%% @see binary_comp/2
binary_comp_template(Node) ->
case unwrap(Node) of
{bc, _, Template, _} ->
Template;
Node1 ->
(data(Node1))#binary_comp.template
end.
%% =====================================================================
%% @spec binary_comp_body(syntaxTree()) -> [syntaxTree()]
%%
%% @doc Returns the list of body subtrees of a <code>binary_comp</code>
%% node.
%%
%% @see binary_comp/2
binary_comp_body(Node) ->
case unwrap(Node) of
{bc, _, _, Body} ->
Body;
Node1 ->
(data(Node1))#binary_comp.body
end.
%% =====================================================================
%% @spec query_expr(Body::syntaxTree()) -> syntaxTree()
%%
%% @doc Creates an abstract Mnemosyne query expression. The result
%% represents "<code>query <em>Body</em> end</code>".
%%
%% @see query_expr_body/1
%% @see record_access/2
%% @see rule/2
%% type(Node) = query_expr
%% data(Node) = syntaxTree()
%%
%% `erl_parse' representation:
%%
%% {'query', Pos, Body}
%%
%% Body = erl_parse()
query_expr(Body) ->
tree(query_expr, Body).
revert_query_expr(Node) ->
Pos = get_pos(Node),
Body = list_comp_body(Node),
{'query', Pos, Body}.
%% =====================================================================
%% @spec query_expr_body(syntaxTree()) -> syntaxTree()
%%
%% @doc Returns the body subtree of a <code>query_expr</code> node.
%%
%% @see query_expr/1
query_expr_body(Node) ->
case unwrap(Node) of
{'query', _, Body} ->
Body;
Node1 ->
data(Node1)
end.
%% =====================================================================
%% @spec rule(Name::syntaxTree(), Clauses::[syntaxTree()]) ->
%% syntaxTree()
%%
%% @doc Creates an abstract Mnemosyne rule. If <code>Clauses</code> is
%% <code>[C1, ..., Cn]</code>, the results represents
%% "<code><em>Name</em> <em>C1</em>; ...; <em>Name</em>
%% <em>Cn</em>.</code>". More exactly, if each <code>Ci</code>
%% represents "<code>(<em>Pi1</em>, ..., <em>Pim</em>) <em>Gi</em> ->
%% <em>Bi</em></code>", then the result represents
%% "<code><em>Name</em>(<em>P11</em>, ..., <em>P1m</em>) <em>G1</em> :-
%% <em>B1</em>; ...; <em>Name</em>(<em>Pn1</em>, ..., <em>Pnm</em>)
%% <em>Gn</em> :- <em>Bn</em>.</code>". Rules are source code forms.
%%
%% @see rule_name/1
%% @see rule_clauses/1
%% @see rule_arity/1
%% @see is_form/1
%% @see function/2
-record(rule, {name, clauses}).
%% type(Node) = rule
%% data(Node) = #rule{name :: Name, clauses :: Clauses}
%%
%% Name = syntaxTree()
%% Clauses = [syntaxTree()]
%%
%% (See `function' for notes on why the arity is not stored.)
%%
%% `erl_parse' representation:
%%
%% {rule, Pos, Name, Arity, Clauses}
%%
%% Name = atom()
%% Arity = integer()
%% Clauses = [Clause] \ []
%% Clause = {clause, ...}
%%
%% where the number of patterns in each clause should be equal to
%% the integer `Arity'; see `clause' for documentation on
%% `erl_parse' clauses.
rule(Name, Clauses) ->
tree(rule, #rule{name = Name, clauses = Clauses}).
revert_rule(Node) ->
Name = rule_name(Node),
Clauses = [revert_clause(C) || C <- rule_clauses(Node)],
Pos = get_pos(Node),
case type(Name) of
atom ->
A = rule_arity(Node),
{rule, Pos, concrete(Name), A, Clauses};
_ ->
Node
end.
%% =====================================================================
%% @spec rule_name(syntaxTree()) -> syntaxTree()
%%
%% @doc Returns the name subtree of a <code>rule</code> node.
%%
%% @see rule/2
rule_name(Node) ->
case unwrap(Node) of
{rule, Pos, Name, _, _} ->
set_pos(atom(Name), Pos);
Node1 ->
(data(Node1))#rule.name
end.
%% =====================================================================
%% @spec rule_clauses(syntaxTree()) -> [syntaxTree()]
%%
%% @doc Returns the list of clause subtrees of a <code>rule</code> node.
%%
%% @see rule/2
rule_clauses(Node) ->
case unwrap(Node) of
{rule, _, _, _, Clauses} ->
Clauses;
Node1 ->
(data(Node1))#rule.clauses
end.
%% =====================================================================
%% @spec rule_arity(Node::syntaxTree()) -> integer()
%%
%% @doc Returns the arity of a <code>rule</code> node. The result is the
%% number of parameter patterns in the first clause of the rule;
%% subsequent clauses are ignored.
%%
%% <p>An exception is thrown if <code>rule_clauses(Node)</code> returns
%% an empty list, or if the first element of that list is not a syntax
%% tree <code>C</code> of type <code>clause</code> such that
%% <code>clause_patterns(C)</code> is a nonempty list.</p>
%%
%% @see rule/2
%% @see rule_clauses/1
%% @see clause/3
%% @see clause_patterns/1
rule_arity(Node) ->
%% Note that this never accesses the arity field of
%% `erl_parse' rule nodes.
length(clause_patterns(hd(rule_clauses(Node)))).
%% =====================================================================
%% @spec generator(Pattern::syntaxTree(), Body::syntaxTree()) ->
%% syntaxTree()
%%
%% @doc Creates an abstract generator. The result represents
%% "<code><em>Pattern</em> <- <em>Body</em></code>".
%%
%% @see generator_pattern/1
%% @see generator_body/1
%% @see list_comp/2
%% @see binary_comp/2
-record(generator, {pattern, body}).
%% type(Node) = generator
%% data(Node) = #generator{pattern :: Pattern, body :: Body}
%%
%% Pattern = Argument = syntaxTree()
%%
%% `erl_parse' representation:
%%
%% {generate, Pos, Pattern, Body}
%%
%% Pattern = Body = erl_parse()
generator(Pattern, Body) ->
tree(generator, #generator{pattern = Pattern, body = Body}).
revert_generator(Node) ->
Pos = get_pos(Node),
Pattern = generator_pattern(Node),
Body = generator_body(Node),
{generate, Pos, Pattern, Body}.
%% =====================================================================
%% @spec generator_pattern(syntaxTree()) -> syntaxTree()
%%
%% @doc Returns the pattern subtree of a <code>generator</code> node.
%%
%% @see generator/2
generator_pattern(Node) ->
case unwrap(Node) of
{generate, _, Pattern, _} ->
Pattern;
Node1 ->
(data(Node1))#generator.pattern
end.
%% =====================================================================
%% @spec generator_body(syntaxTree()) -> syntaxTree()
%%
%% @doc Returns the body subtree of a <code>generator</code> node.
%%
%% @see generator/2
generator_body(Node) ->
case unwrap(Node) of
{generate, _, _, Body} ->
Body;
Node1 ->
(data(Node1))#generator.body
end.
%% =====================================================================
%% @spec binary_generator(Pattern::syntaxTree(), Body::syntaxTree()) ->
%% syntaxTree()
%%
%% @doc Creates an abstract binary_generator. The result represents
%% "<code><em>Pattern</em> <- <em>Body</em></code>".
%%
%% @see binary_generator_pattern/1
%% @see binary_generator_body/1
%% @see list_comp/2
%% @see binary_comp/2
-record(binary_generator, {pattern, body}).
%% type(Node) = binary_generator
%% data(Node) = #binary_generator{pattern :: Pattern, body :: Body}
%%
%% Pattern = Argument = syntaxTree()
%%
%% `erl_parse' representation:
%%
%% {b_generate, Pos, Pattern, Body}
%%
%% Pattern = Body = erl_parse()
binary_generator(Pattern, Body) ->
tree(binary_generator, #binary_generator{pattern = Pattern, body = Body}).
revert_binary_generator(Node) ->
Pos = get_pos(Node),
Pattern = binary_generator_pattern(Node),
Body = binary_generator_body(Node),
{b_generate, Pos, Pattern, Body}.
%% =====================================================================
%% @spec binary_generator_pattern(syntaxTree()) -> syntaxTree()
%%
%% @doc Returns the pattern subtree of a <code>generator</code> node.
%%
%% @see binary_generator/2
binary_generator_pattern(Node) ->
case unwrap(Node) of
{b_generate, _, Pattern, _} ->
Pattern;
Node1 ->
(data(Node1))#binary_generator.pattern
end.
%% =====================================================================
%% @spec binary_generator_body(syntaxTree()) -> syntaxTree()
%%
%% @doc Returns the body subtree of a <code>generator</code> node.
%%
%% @see binary_generator/2
binary_generator_body(Node) ->
case unwrap(Node) of
{b_generate, _, _, Body} ->
Body;
Node1 ->
(data(Node1))#binary_generator.body
end.
%% =====================================================================
%% @spec block_expr(Body::[syntaxTree()]) -> syntaxTree()
%%
%% @doc Creates an abstract block expression. If <code>Body</code> is
%% <code>[B1, ..., Bn]</code>, the result represents "<code>begin
%% <em>B1</em>, ..., <em>Bn</em> end</code>".
%%
%% @see block_expr_body/1
%% type(Node) = block_expr
%% data(Node) = Body
%%
%% Body = [syntaxTree()]
%%
%% `erl_parse' representation:
%%
%% {block, Pos, Body}
%%
%% Body = [erl_parse()] \ []
block_expr(Body) ->
tree(block_expr, Body).
revert_block_expr(Node) ->
Pos = get_pos(Node),
Body = block_expr_body(Node),
{block, Pos, Body}.
%% =====================================================================
%% @spec block_expr_body(syntaxTree()) -> [syntaxTree()]
%%
%% @doc Returns the list of body subtrees of a <code>block_expr</code>
%% node.
%%
%% @see block_expr/1
block_expr_body(Node) ->
case unwrap(Node) of
{block, _, Body} ->
Body;
Node1 ->
data(Node1)
end.
%% =====================================================================
%% @spec if_expr(Clauses::[syntaxTree()]) -> syntaxTree()
%%
%% @doc Creates an abstract if-expression. If <code>Clauses</code> is
%% <code>[C1, ..., Cn]</code>, the result represents "<code>if
%% <em>C1</em>; ...; <em>Cn</em> end</code>". More exactly, if each
%% <code>Ci</code> represents "<code>() <em>Gi</em> ->
%% <em>Bi</em></code>", then the result represents "<code>if
%% <em>G1</em> -> <em>B1</em>; ...; <em>Gn</em> -> <em>Bn</em>
%% end</code>".
%%
%% @see if_expr_clauses/1
%% @see clause/3
%% @see case_expr/2
%% type(Node) = if_expr
%% data(Node) = Clauses
%%
%% Clauses = [syntaxTree()]
%%
%% `erl_parse' representation:
%%
%% {'if', Pos, Clauses}
%%
%% Clauses = [Clause] \ []
%% Clause = {clause, ...}
%%
%% See `clause' for documentation on `erl_parse' clauses.
if_expr(Clauses) ->
tree(if_expr, Clauses).
revert_if_expr(Node) ->
Pos = get_pos(Node),
Clauses = [revert_clause(C) || C <- if_expr_clauses(Node)],
{'if', Pos, Clauses}.
%% =====================================================================
%% @spec if_expr_clauses(syntaxTree()) -> [syntaxTree()]
%%
%% @doc Returns the list of clause subtrees of an <code>if_expr</code>
%% node.
%%
%% @see if_expr/1
if_expr_clauses(Node) ->
case unwrap(Node) of
{'if', _, Clauses} ->
Clauses;
Node1 ->
data(Node1)
end.
%% =====================================================================
%% @spec case_expr(Argument::syntaxTree(), Clauses::[syntaxTree()]) ->
%% syntaxTree()
%%
%% @doc Creates an abstract case-expression. If <code>Clauses</code> is
%% <code>[C1, ..., Cn]</code>, the result represents "<code>case
%% <em>Argument</em> of <em>C1</em>; ...; <em>Cn</em> end</code>". More
%% exactly, if each <code>Ci</code> represents "<code>(<em>Pi</em>)
%% <em>Gi</em> -> <em>Bi</em></code>", then the result represents
%% "<code>case <em>Argument</em> of <em>P1</em> <em>G1</em> ->
%% <em>B1</em>; ...; <em>Pn</em> <em>Gn</em> -> <em>Bn</em> end</code>".
%%
%% @see case_expr_clauses/1
%% @see case_expr_argument/1
%% @see clause/3
%% @see if_expr/1
%% @see cond_expr/1
-record(case_expr, {argument, clauses}).
%% type(Node) = case_expr
%% data(Node) = #case_expr{argument :: Argument,
%% clauses :: Clauses}
%%
%% Argument = syntaxTree()
%% Clauses = [syntaxTree()]
%%
%% `erl_parse' representation:
%%
%% {'case', Pos, Argument, Clauses}
%%
%% Argument = erl_parse()
%% Clauses = [Clause] \ []
%% Clause = {clause, ...}
%%
%% See `clause' for documentation on `erl_parse' clauses.
case_expr(Argument, Clauses) ->
tree(case_expr, #case_expr{argument = Argument,
clauses = Clauses}).
revert_case_expr(Node) ->
Pos = get_pos(Node),
Argument = case_expr_argument(Node),
Clauses = [revert_clause(C) || C <- case_expr_clauses(Node)],
{'case', Pos, Argument, Clauses}.
%% =====================================================================
%% @spec case_expr_argument(syntaxTree()) -> syntaxTree()
%%
%% @doc Returns the argument subtree of a <code>case_expr</code> node.
%%
%% @see case_expr/2
case_expr_argument(Node) ->
case unwrap(Node) of
{'case', _, Argument, _} ->
Argument;
Node1 ->
(data(Node1))#case_expr.argument
end.
%% =====================================================================
%% @spec case_expr_clauses(syntaxTree()) -> [syntaxTree()]
%%
%% @doc Returns the list of clause subtrees of a <code>case_expr</code>
%% node.
%%
%% @see case_expr/2
case_expr_clauses(Node) ->
case unwrap(Node) of
{'case', _, _, Clauses} ->
Clauses;
Node1 ->
(data(Node1))#case_expr.clauses
end.
%% =====================================================================
%% @spec cond_expr(Clauses::[syntaxTree()]) -> syntaxTree()
%%
%% @doc Creates an abstract cond-expression. If <code>Clauses</code> is
%% <code>[C1, ..., Cn]</code>, the result represents "<code>cond
%% <em>C1</em>; ...; <em>Cn</em> end</code>". More exactly, if each
%% <code>Ci</code> represents "<code>() <em>Ei</em> ->
%% <em>Bi</em></code>", then the result represents "<code>cond
%% <em>E1</em> -> <em>B1</em>; ...; <em>En</em> -> <em>Bn</em>
%% end</code>".
%%
%% @see cond_expr_clauses/1
%% @see clause/3
%% @see case_expr/2
%% type(Node) = cond_expr
%% data(Node) = Clauses
%%
%% Clauses = [syntaxTree()]
%%
%% `erl_parse' representation:
%%
%% {'cond', Pos, Clauses}
%%
%% Clauses = [Clause] \ []
%% Clause = {clause, ...}
%%
%% See `clause' for documentation on `erl_parse' clauses.
cond_expr(Clauses) ->
tree(cond_expr, Clauses).
revert_cond_expr(Node) ->
Pos = get_pos(Node),
Clauses = [revert_clause(C) || C <- cond_expr_clauses(Node)],
{'cond', Pos, Clauses}.
%% =====================================================================
%% @spec cond_expr_clauses(syntaxTree()) -> [syntaxTree()]
%%
%% @doc Returns the list of clause subtrees of a <code>cond_expr</code>
%% node.
%%
%% @see cond_expr/1
cond_expr_clauses(Node) ->
case unwrap(Node) of
{'cond', _, Clauses} ->
Clauses;
Node1 ->
data(Node1)
end.
%% =====================================================================
%% @spec receive_expr(Clauses) -> syntaxTree()
%% @equiv receive_expr(Clauses, none, [])
receive_expr(Clauses) ->
receive_expr(Clauses, none, []).
%% =====================================================================
%% @spec receive_expr(Clauses::[syntaxTree()], Timeout,
%% Action::[syntaxTree()]) -> syntaxTree()
%% Timeout = none | syntaxTree()
%%
%% @doc Creates an abstract receive-expression. If <code>Timeout</code>
%% is <code>none</code>, the result represents "<code>receive
%% <em>C1</em>; ...; <em>Cn</em> end</code>" (the <code>Action</code>
%% argument is ignored). Otherwise, if <code>Clauses</code> is
%% <code>[C1, ..., Cn]</code> and <code>Action</code> is <code>[A1, ...,
%% Am]</code>, the result represents "<code>receive <em>C1</em>; ...;
%% <em>Cn</em> after <em>Timeout</em> -> <em>A1</em>, ..., <em>Am</em>
%% end</code>". More exactly, if each <code>Ci</code> represents
%% "<code>(<em>Pi</em>) <em>Gi</em> -> <em>Bi</em></code>", then the
%% result represents "<code>receive <em>P1</em> <em>G1</em> ->
%% <em>B1</em>; ...; <em>Pn</em> <em>Gn</em> -> <em>Bn</em> ...
%% end</code>".
%%
%% <p>Note that in Erlang, a receive-expression must have at least one
%% clause if no timeout part is specified.</p>
%%
%% @see receive_expr_clauses/1
%% @see receive_expr_timeout/1
%% @see receive_expr_action/1
%% @see receive_expr/1
%% @see clause/3
%% @see case_expr/2
-record(receive_expr, {clauses, timeout, action}).
%% type(Node) = receive_expr
%% data(Node) = #receive_expr{clauses :: Clauses,
%% timeout :: Timeout,
%% action :: Action}
%%
%% Clauses = [syntaxTree()]
%% Timeout = none | syntaxTree()
%% Action = [syntaxTree()]
%%
%% `erl_parse' representation:
%%
%% {'receive', Pos, Clauses}
%% {'receive', Pos, Clauses, Timeout, Action}
%%
%% Clauses = [Clause] \ []
%% Clause = {clause, ...}
%% Timeout = erl_parse()
%% Action = [erl_parse()] \ []
%%
%% See `clause' for documentation on `erl_parse' clauses.
receive_expr(Clauses, Timeout, Action) ->
%% If `Timeout' is `none', we always replace the actual
%% `Action' argument with an empty list, since
%% `receive_expr_action' should in that case return the empty
%% list regardless.
Action1 = case Timeout of
none -> [];
_ -> Action
end,
tree(receive_expr, #receive_expr{clauses = Clauses,
timeout = Timeout,
action = Action1}).
revert_receive_expr(Node) ->
Pos = get_pos(Node),
Clauses = [revert_clause(C) || C <- receive_expr_clauses(Node)],
Timeout = receive_expr_timeout(Node),
Action = receive_expr_action(Node),
case Timeout of
none ->
{'receive', Pos, Clauses};
_ ->
{'receive', Pos, Clauses, Timeout, Action}
end.
%% =====================================================================
%% @spec receive_expr_clauses(syntaxTree()) -> [syntaxTree()]
%% type(Node) = receive_expr
%%
%% @doc Returns the list of clause subtrees of a
%% <code>receive_expr</code> node.
%%
%% @see receive_expr/3
receive_expr_clauses(Node) ->
case unwrap(Node) of
{'receive', _, Clauses} ->
Clauses;
{'receive', _, Clauses, _, _} ->
Clauses;
Node1 ->
(data(Node1))#receive_expr.clauses
end.
%% =====================================================================
%% @spec receive_expr_timeout(Node::syntaxTree()) -> Timeout
%% Timeout = none | syntaxTree()
%%
%% @doc Returns the timeout subtree of a <code>receive_expr</code> node,
%% if any. If <code>Node</code> represents "<code>receive <em>C1</em>;
%% ...; <em>Cn</em> end</code>", <code>none</code> is returned.
%% Otherwise, if <code>Node</code> represents "<code>receive
%% <em>C1</em>; ...; <em>Cn</em> after <em>Timeout</em> -> ... end</code>",
%% <code>Timeout</code> is returned.
%%
%% @see receive_expr/3
receive_expr_timeout(Node) ->
case unwrap(Node) of
{'receive', _, _} ->
none;
{'receive', _, _, Timeout, _} ->
Timeout;
Node1 ->
(data(Node1))#receive_expr.timeout
end.
%% =====================================================================
%% @spec receive_expr_action(Node::syntaxTree()) -> [syntaxTree()]
%%
%% @doc Returns the list of action body subtrees of a
%% <code>receive_expr</code> node. If <code>Node</code> represents
%% "<code>receive <em>C1</em>; ...; <em>Cn</em> end</code>", this is the
%% empty list.
%%
%% @see receive_expr/3
receive_expr_action(Node) ->
case unwrap(Node) of
{'receive', _, _} ->
[];
{'receive', _, _, _, Action} ->
Action;
Node1 ->
(data(Node1))#receive_expr.action
end.
%% =====================================================================
%% @spec try_expr(Body::syntaxTree(), Handlers::[syntaxTree()]) ->
%% syntaxTree()
%% @equiv try_expr(Body, [], Handlers)
try_expr(Body, Handlers) ->
try_expr(Body, [], Handlers).
%% =====================================================================
%% @spec try_expr(Body::syntaxTree(), Clauses::[syntaxTree()],
%% Handlers::[syntaxTree()]) -> syntaxTree()
%% @equiv try_expr(Body, Clauses, Handlers, [])
try_expr(Body, Clauses, Handlers) ->
try_expr(Body, Clauses, Handlers, []).
%% =====================================================================
%% @spec try_after_expr(Body::syntaxTree(), After::[syntaxTree()]) ->
%% syntaxTree()
%% @equiv try_expr(Body, [], [], After)
try_after_expr(Body, After) ->
try_expr(Body, [], [], After).
%% =====================================================================
%% @spec try_expr(Body::[syntaxTree()], Clauses::[syntaxTree()],
%% Handlers::[syntaxTree()], After::[syntaxTree()]) ->
%% syntaxTree()
%%
%% @doc Creates an abstract try-expression. If <code>Body</code> is
%% <code>[B1, ..., Bn]</code>, <code>Clauses</code> is <code>[C1, ...,
%% Cj]</code>, <code>Handlers</code> is <code>[H1, ..., Hk]</code>, and
%% <code>After</code> is <code>[A1, ..., Am]</code>, the result
%% represents "<code>try <em>B1</em>, ..., <em>Bn</em> of <em>C1</em>;
%% ...; <em>Cj</em> catch <em>H1</em>; ...; <em>Hk</em> after
%% <em>A1</em>, ..., <em>Am</em> end</code>". More exactly, if each
%% <code>Ci</code> represents "<code>(<em>CPi</em>) <em>CGi</em> ->
%% <em>CBi</em></code>", and each <code>Hi</code> represents
%% "<code>(<em>HPi</em>) <em>HGi</em> -> <em>HBi</em></code>", then the
%% result represents "<code>try <em>B1</em>, ..., <em>Bn</em> of
%% <em>CP1</em> <em>CG1</em> -> <em>CB1</em>; ...; <em>CPj</em>
%% <em>CGj</em> -> <em>CBj</em> catch <em>HP1</em> <em>HG1</em> ->
%% <em>HB1</em>; ...; <em>HPk</em> <em>HGk</em> -> <em>HBk</em> after
%% <em>A1</em>, ..., <em>Am</em> end</code>"; cf.
%% <code>case_expr/2</code>. If <code>Clauses</code> is the empty list,
%% the <code>of ...</code> section is left out. If <code>After</code> is
%% the empty list, the <code>after ...</code> section is left out. If
%% <code>Handlers</code> is the empty list, and <code>After</code> is
%% nonempty, the <code>catch ...</code> section is left out.
%%
%% @see try_expr_body/1
%% @see try_expr_clauses/1
%% @see try_expr_handlers/1
%% @see try_expr_after/1
%% @see try_expr/2
%% @see try_expr/3
%% @see try_after_expr/2
%% @see clause/3
%% @see class_qualifier/2
%% @see case_expr/2
-record(try_expr, {body, clauses, handlers, 'after'}).
%% type(Node) = try_expr
%% data(Node) = #try_expr{body :: Body,
%% clauses :: Clauses,
%% handlers :: Clauses,
%% after :: Body}
%%
%% Body = syntaxTree()
%% Clauses = [syntaxTree()]
%%
%% `erl_parse' representation:
%%
%% {'try', Pos, Body, Clauses, Handlers, After}
%%
%% Body = [erl_parse()]
%% Clauses = [Clause]
%% Handlers = [Clause] \ []
%% Clause = {clause, ...}
%% After = [erl_parse()]
%%
%% See `clause' for documentation on `erl_parse' clauses.
try_expr(Body, Clauses, Handlers, After) ->
tree(try_expr, #try_expr{body = Body,
clauses = Clauses,
handlers = Handlers,
'after' = After}).
revert_try_expr(Node) ->
Pos = get_pos(Node),
Body = try_expr_body(Node),
Clauses = [revert_clause(C) || C <- try_expr_clauses(Node)],
Handlers = [revert_try_clause(C) || C <- try_expr_handlers(Node)],
After = try_expr_after(Node),
{'try', Pos, Body, Clauses, Handlers, After}.
%% =====================================================================
%% @spec try_expr_body(syntaxTree()) -> [syntaxTree()]
%%
%% @doc Returns the list of body subtrees of a <code>try_expr</code>
%% node.
%%
%% @see try_expr/4
try_expr_body(Node) ->
case unwrap(Node) of
{'try', _, Body, _, _, _} ->
Body;
Node1 ->
(data(Node1))#try_expr.body
end.
%% =====================================================================
%% @spec try_expr_clauses(Node::syntaxTree()) -> [syntaxTree()]
%%
%% @doc Returns the list of case-clause subtrees of a
%% <code>try_expr</code> node. If <code>Node</code> represents
%% "<code>try <em>Body</em> catch <em>H1</em>; ...; <em>Hn</em>
%% end</code>", the result is the empty list.
%%
%% @see try_expr/4
try_expr_clauses(Node) ->
case unwrap(Node) of
{'try', _, _, Clauses, _, _} ->
Clauses;
Node1 ->
(data(Node1))#try_expr.clauses
end.
%% =====================================================================
%% @spec try_expr_handlers(syntaxTree()) -> [syntaxTree()]
%%
%% @doc Returns the list of handler-clause subtrees of a
%% <code>try_expr</code> node.
%%
%% @see try_expr/4
try_expr_handlers(Node) ->
case unwrap(Node) of
{'try', _, _, _, Handlers, _} ->
unfold_try_clauses(Handlers);
Node1 ->
(data(Node1))#try_expr.handlers
end.
%% =====================================================================
%% @spec try_expr_after(syntaxTree()) -> [syntaxTree()]
%%
%% @doc Returns the list of "after" subtrees of a <code>try_expr</code>
%% node.
%%
%% @see try_expr/4
try_expr_after(Node) ->
case unwrap(Node) of
{'try', _, _, _, _, After} ->
After;
Node1 ->
(data(Node1))#try_expr.'after'
end.
%% =====================================================================
%% @spec class_qualifier(Class::syntaxTree(), Body::syntaxTree()) ->
%% syntaxTree()
%%
%% @doc Creates an abstract class qualifier. The result represents
%% "<code><em>Class</em>:<em>Body</em></code>".
%%
%% @see class_qualifier_argument/1
%% @see class_qualifier_body/1
%% @see try_expr/4
-record(class_qualifier, {class, body}).
%% type(Node) = class_qualifier
%% data(Node) = #class_qualifier{class :: Class, body :: Body}
%%
%% Class = Body = syntaxTree()
class_qualifier(Class, Body) ->
tree(class_qualifier,
#class_qualifier{class = Class, body = Body}).
%% =====================================================================
%% @spec class_qualifier_argument(syntaxTree()) -> syntaxTree()
%%
%% @doc Returns the argument (the class) subtree of a
%% <code>class_qualifier</code> node.
%%
%% @see class_qualifier/2
class_qualifier_argument(Node) ->
(data(Node))#class_qualifier.class.
%% =====================================================================
%% @spec class_qualifier_body(syntaxTree()) -> syntaxTree()
%%
%% @doc Returns the body subtree of a <code>class_qualifier</code> node.
%%
%% @see class_qualifier/2
class_qualifier_body(Node) ->
(data(Node))#class_qualifier.body.
%% =====================================================================
%% @spec implicit_fun(Name::syntaxTree(), Arity::syntaxTree()) ->
%% syntaxTree()
%%
%% @doc Creates an abstract "implicit fun" expression. If
%% <code>Arity</code> is <code>none</code>, this is equivalent to
%% <code>implicit_fun(Name)</code>, otherwise it is equivalent to
%% <code>implicit_fun(arity_qualifier(Name, Arity))</code>.
%%
%% (This is a utility function.)
%%
%% @see implicit_fun/1
%% @see implicit_fun/3
implicit_fun(Name, none) ->
implicit_fun(Name);
implicit_fun(Name, Arity) ->
implicit_fun(arity_qualifier(Name, Arity)).
%% =====================================================================
%% @spec implicit_fun(Module::syntaxTree(), Name::syntaxTree(),
%% Arity::syntaxTree()) -> syntaxTree()
%%
%% @doc Creates an abstract module-qualified "implicit fun" expression.
%% If <code>Module</code> is <code>none</code>, this is equivalent to
%% <code>implicit_fun(Name, Arity)</code>, otherwise it is equivalent to
%% <code>implicit_fun(module_qualifier(Module, arity_qualifier(Name,
%% Arity))</code>.
%%
%% (This is a utility function.)
%%
%% @see implicit_fun/1
%% @see implicit_fun/2
implicit_fun(none, Name, Arity) ->
implicit_fun(Name, Arity);
implicit_fun(Module, Name, Arity) ->
implicit_fun(module_qualifier(Module, arity_qualifier(Name, Arity))).
%% =====================================================================
%% @spec implicit_fun(Name::syntaxTree()) -> syntaxTree()
%%
%% @doc Creates an abstract "implicit fun" expression. The result
%% represents "<code>fun <em>Name</em></code>". <code>Name</code> should
%% represent either <code><em>F</em>/<em>A</em></code> or
%% <code><em>M</em>:<em>F</em>/<em>A</em></code>
%%
%% @see implicit_fun_name/1
%% @see implicit_fun/2
%% @see implicit_fun/3
%% @see arity_qualifier/2
%% @see module_qualifier/2
%% type(Node) = implicit_fun
%% data(Node) = syntaxTree()
%%
%% `erl_parse' representation:
%%
%% {'fun', Pos, {function, Name, Arity}}
%% {'fun', Pos, {function, Module, Name, Arity}}
%%
%% Module = atom()
%% Name = atom()
%% Arity = integer()
implicit_fun(Name) ->
tree(implicit_fun, Name).
revert_implicit_fun(Node) ->
Pos = get_pos(Node),
Name = implicit_fun_name(Node),
case type(Name) of
arity_qualifier ->
F = arity_qualifier_body(Name),
A = arity_qualifier_argument(Name),
case {type(F), type(A)} of
{atom, integer} ->
{'fun', Pos,
{function, concrete(F), concrete(A)}};
_ ->
Node
end;
module_qualifier ->
M = module_qualifier_argument(Name),
Name1 = module_qualifier_body(Name),
F = arity_qualifier_body(Name1),
A = arity_qualifier_argument(Name1),
case {type(M), type(F), type(A)} of
{atom, atom, integer} ->
{'fun', Pos,
{function, concrete(M), concrete(F), concrete(A)}};
_ ->
Node
end;
_ ->
Node
end.
%% =====================================================================
%% @spec implicit_fun_name(Node::syntaxTree()) -> syntaxTree()
%%
%% @doc Returns the name subtree of an <code>implicit_fun</code> node.
%%
%% <p>Note: if <code>Node</code> represents "<code>fun
%% <em>N</em>/<em>A</em></code>" or "<code>fun
%% <em>M</em>:<em>N</em>/<em>A</em></code>", then the result is the
%% subtree representing "<code><em>N</em>/<em>A</em></code>" or
%% "<code><em>M</em>:<em>N</em>/<em>A</em></code>", respectively.</p>
%%
%% @see implicit_fun/1
%% @see arity_qualifier/2
%% @see module_qualifier/2
implicit_fun_name(Node) ->
case unwrap(Node) of
{'fun', Pos, {function, Atom, Arity}} ->
arity_qualifier(set_pos(atom(Atom), Pos),
set_pos(integer(Arity), Pos));
{'fun', Pos, {function, Module, Atom, Arity}} ->
module_qualifier(set_pos(atom(Module), Pos),
arity_qualifier(
set_pos(atom(Atom), Pos),
set_pos(integer(Arity), Pos)));
Node1 ->
data(Node1)
end.
%% =====================================================================
%% @spec fun_expr(Clauses::[syntaxTree()]) -> syntaxTree()
%%
%% @doc Creates an abstract fun-expression. If <code>Clauses</code> is
%% <code>[C1, ..., Cn]</code>, the result represents "<code>fun
%% <em>C1</em>; ...; <em>Cn</em> end</code>". More exactly, if each
%% <code>Ci</code> represents "<code>(<em>Pi1</em>, ..., <em>Pim</em>)
%% <em>Gi</em> -> <em>Bi</em></code>", then the result represents
%% "<code>fun (<em>P11</em>, ..., <em>P1m</em>) <em>G1</em> ->
%% <em>B1</em>; ...; (<em>Pn1</em>, ..., <em>Pnm</em>) <em>Gn</em> ->
%% <em>Bn</em> end</code>".
%%
%% @see fun_expr_clauses/1
%% @see fun_expr_arity/1
%% type(Node) = fun_expr
%% data(Node) = Clauses
%%
%% Clauses = [syntaxTree()]
%%
%% (See `function' for notes; e.g. why the arity is not stored.)
%%
%% `erl_parse' representation:
%%
%% {'fun', Pos, {clauses, Clauses}}
%%
%% Clauses = [Clause] \ []
%% Clause = {clause, ...}
%%
%% See `clause' for documentation on `erl_parse' clauses.
fun_expr(Clauses) ->
tree(fun_expr, Clauses).
revert_fun_expr(Node) ->
Clauses = [revert_clause(C) || C <- fun_expr_clauses(Node)],
Pos = get_pos(Node),
{'fun', Pos, {clauses, Clauses}}.
%% =====================================================================
%% @spec fun_expr_clauses(syntaxTree()) -> [syntaxTree()]
%%
%% @doc Returns the list of clause subtrees of a <code>fun_expr</code>
%% node.
%%
%% @see fun_expr/1
fun_expr_clauses(Node) ->
case unwrap(Node) of
{'fun', _, {clauses, Clauses}} ->
Clauses;
Node1 ->
data(Node1)
end.
%% =====================================================================
%% @spec fun_expr_arity(syntaxTree()) -> integer()
%%
%% @doc Returns the arity of a <code>fun_expr</code> node. The result is
%% the number of parameter patterns in the first clause of the
%% fun-expression; subsequent clauses are ignored.
%%
%% <p>An exception is thrown if <code>fun_expr_clauses(Node)</code>
%% returns an empty list, or if the first element of that list is not a
%% syntax tree <code>C</code> of type <code>clause</code> such that
%% <code>clause_patterns(C)</code> is a nonempty list.</p>
%%
%% @see fun_expr/1
%% @see fun_expr_clauses/1
%% @see clause/3
%% @see clause_patterns/1
fun_expr_arity(Node) ->
length(clause_patterns(hd(fun_expr_clauses(Node)))).
%% =====================================================================
%% @spec parentheses(Body::syntaxTree()) -> syntaxTree()
%%
%% @doc Creates an abstract parenthesised expression. The result
%% represents "<code>(<em>Body</em>)</code>", independently of the
%% context.
%%
%% @see parentheses_body/1
%% type(Node) = parentheses
%% data(Node) = syntaxTree()
parentheses(Expr) ->
tree(parentheses, Expr).
revert_parentheses(Node) ->
parentheses_body(Node).
%% =====================================================================
%% @spec parentheses_body(syntaxTree()) -> syntaxTree()
%%
%% @doc Returns the body subtree of a <code>parentheses</code> node.
%%
%% @see parentheses/1
parentheses_body(Node) ->
data(Node).
%% =====================================================================
%% @spec macro(Name) -> syntaxTree()
%% @equiv macro(Name, none)
macro(Name) ->
macro(Name, none).
%% =====================================================================
%% @spec macro(Name::syntaxTree(), Arguments) -> syntaxTree()
%% Arguments = none | [syntaxTree()]
%%
%% @doc Creates an abstract macro application. If <code>Arguments</code>
%% is <code>none</code>, the result represents
%% "<code>?<em>Name</em></code>", otherwise, if <code>Arguments</code>
%% is <code>[A1, ..., An]</code>, the result represents
%% "<code>?<em>Name</em>(<em>A1</em>, ..., <em>An</em>)</code>".
%%
%% <p>Notes: if <code>Arguments</code> is the empty list, the result
%% will thus represent "<code>?<em>Name</em>()</code>", including a pair
%% of matching parentheses.</p>
%%
%% <p>The only syntactical limitation imposed by the preprocessor on the
%% arguments to a macro application (viewed as sequences of tokens) is
%% that they must be balanced with respect to parentheses, brackets,
%% <code>begin ... end</code>, <code>case ... end</code>, etc. The
%% <code>text</code> node type can be used to represent arguments which
%% are not regular Erlang constructs.</p>
%%
%% @see macro_name/1
%% @see macro_arguments/1
%% @see macro/1
%% @see text/1
-record(macro, {name, arguments}).
%% type(Node) = macro
%% data(Node) = #macro{name :: Name, arguments :: Arguments}
%%
%% Name = syntaxTree()
%% Arguments = none | [syntaxTree()]
macro(Name, Arguments) ->
tree(macro, #macro{name = Name, arguments = Arguments}).
%% =====================================================================
%% @spec macro_name(syntaxTree()) -> syntaxTree()
%%
%% @doc Returns the name subtree of a <code>macro</code> node.
%%
%% @see macro/2
macro_name(Node) ->
(data(Node))#macro.name.
%% =====================================================================
%% @spec macro_arguments(Node::syntaxTree()) -> none | [syntaxTree()]
%%
%% @doc Returns the list of argument subtrees of a <code>macro</code>
%% node, if any. If <code>Node</code> represents
%% "<code>?<em>Name</em></code>", <code>none</code> is returned.
%% Otherwise, if <code>Node</code> represents
%% "<code>?<em>Name</em>(<em>A1</em>, ..., <em>An</em>)</code>",
%% <code>[A1, ..., An]</code> is returned.
%%
%% @see macro/2
macro_arguments(Node) ->
(data(Node))#macro.arguments.
%% =====================================================================
%% @spec abstract(Term::term()) -> syntaxTree()
%%
%% @doc Returns the syntax tree corresponding to an Erlang term.
%% <code>Term</code> must be a literal term, i.e., one that can be
%% represented as a source code literal. Thus, it may not contain a
%% process identifier, port, reference, binary or function value as a
%% subterm. The function recognises printable strings, in order to get a
%% compact and readable representation. Evaluation fails with reason
%% <code>badarg</code> if <code>Term</code> is not a literal term.
%%
%% @see concrete/1
%% @see is_literal/1
abstract([H | T] = L) when is_integer(H) ->
case is_printable(L) of
true ->
string(L);
false ->
abstract_tail(H, T)
end;
abstract([H | T]) ->
abstract_tail(H, T);
abstract(T) when is_atom(T) ->
atom(T);
abstract(T) when is_integer(T) ->
integer(T);
abstract(T) when is_float(T) ->
make_float(T); % (not `float', which would call the BIF)
abstract([]) ->
nil();
abstract(T) when is_tuple(T) ->
tuple(abstract_list(tuple_to_list(T)));
abstract(T) when is_binary(T) ->
binary([binary_field(integer(B)) || B <- binary_to_list(T)]);
abstract(T) ->
erlang:error({badarg, T}).
abstract_list([T | Ts]) ->
[abstract(T) | abstract_list(Ts)];
abstract_list([]) ->
[].
%% This is entered when we might have a sequence of conses that might or
%% might not be a proper list, but which should not be considered as a
%% potential string, to avoid unnecessary checking. This also avoids
%% that a list like `[4711, 42, 10]' could be abstracted to represent
%% `[4711 | "*\n"]'.
abstract_tail(H1, [H2 | T]) ->
%% Recall that `cons' does "intelligent" composition
cons(abstract(H1), abstract_tail(H2, T));
abstract_tail(H, T) ->
cons(abstract(H), abstract(T)).
%% =====================================================================
%% @spec concrete(Node::syntaxTree()) -> term()
%%
%% @doc Returns the Erlang term represented by a syntax tree. Evaluation
%% fails with reason <code>badarg</code> if <code>Node</code> does not
%% represent a literal term.
%%
%% <p>Note: Currently, the set of syntax trees which have a concrete
%% representation is larger than the set of trees which can be built
%% using the function <code>abstract/1</code>. An abstract character
%% will be concretised as an integer, while <code>abstract/1</code> does
%% not at present yield an abstract character for any input. (Use the
%% <code>char/1</code> function to explicitly create an abstract
%% character.)</p>
%%
%% @see abstract/1
%% @see is_literal/1
%% @see char/1
concrete(Node) ->
case type(Node) of
atom ->
atom_value(Node);
integer ->
integer_value(Node);
float ->
float_value(Node);
char ->
char_value(Node);
string ->
string_value(Node);
nil ->
[];
list ->
[concrete(list_head(Node))
| concrete(list_tail(Node))];
tuple ->
list_to_tuple(concrete_list(tuple_elements(Node)));
binary ->
Fs = [revert_binary_field(
binary_field(binary_field_body(F),
case binary_field_size(F) of
none -> none;
S ->
revert(S)
end,
binary_field_types(F)))
|| F <- binary_fields(Node)],
{value, B, _} =
eval_bits:expr_grp(Fs, [],
fun(F, _) ->
{value, concrete(F), []}
end, [], true),
B;
_ ->
erlang:error({badarg, Node})
end.
concrete_list([E | Es]) ->
[concrete(E) | concrete_list(Es)];
concrete_list([]) ->
[].
%% =====================================================================
%% @spec is_literal(Node::syntaxTree()) -> bool()
%%
%% @doc Returns <code>true</code> if <code>Node</code> represents a
%% literal term, otherwise <code>false</code>. This function returns
%% <code>true</code> if and only if the value of
%% <code>concrete(Node)</code> is defined.
%%
%% @see abstract/1
%% @see concrete/1
is_literal(T) ->
case type(T) of
atom ->
true;
integer ->
true;
float ->
true;
char->
true;
string ->
true;
nil ->
true;
list ->
is_literal(list_head(T)) andalso is_literal(list_tail(T));
tuple ->
lists:all(fun is_literal/1, tuple_elements(T));
_ ->
false
end.
%% =====================================================================
%% @spec revert(Tree::syntaxTree()) -> syntaxTree()
%%
%% @doc Returns an <code>erl_parse</code>-compatible representation of a
%% syntax tree, if possible. If <code>Tree</code> represents a
%% well-formed Erlang program or expression, the conversion should work
%% without problems. Typically, <code>is_tree/1</code> yields
%% <code>true</code> if conversion failed (i.e., the result is still an
%% abstract syntax tree), and <code>false</code> otherwise.
%%
%% <p>The <code>is_tree/1</code> test is not completely foolproof. For a
%% few special node types (e.g. <code>arity_qualifier</code>), if such a
%% node occurs in a context where it is not expected, it will be left
%% unchanged as a non-reverted subtree of the result. This can only
%% happen if <code>Tree</code> does not actually represent legal Erlang
%% code.</p>
%%
%% @see revert_forms/1
%% @see //stdlib/erl_parse
revert(Node) ->
case is_tree(Node) of
false ->
%% Just remove any wrapper. `erl_parse' nodes never contain
%% abstract syntax tree nodes as subtrees.
unwrap(Node);
true ->
case is_leaf(Node) of
true ->
revert_root(Node);
false ->
%% First revert the subtrees, where possible.
%% (Sometimes, subtrees cannot be reverted out of
%% context, and the real work will be done when the
%% parent node is reverted.)
Gs = [[revert(X) || X <- L] || L <- subtrees(Node)],
%% Then reconstruct the node from the reverted
%% parts, and revert the node itself.
Node1 = update_tree(Node, Gs),
revert_root(Node1)
end
end.
%% Note: The concept of "compatible root node" is not strictly defined.
%% At a minimum, if `make_tree' is used to compose a node `T' from
%% subtrees that are all completely backwards compatible, then the
%% result of `revert_root(T)' should also be completely backwards
%% compatible.
revert_root(Node) ->
case type(Node) of
application ->
revert_application(Node);
atom ->
revert_atom(Node);
attribute ->
revert_attribute(Node);
binary ->
revert_binary(Node);
binary_comp ->
revert_binary_comp(Node);
binary_field ->
revert_binary_field(Node);
binary_generator ->
revert_binary_generator(Node);
block_expr ->
revert_block_expr(Node);
case_expr ->
revert_case_expr(Node);
catch_expr ->
revert_catch_expr(Node);
char ->
revert_char(Node);
clause ->
revert_clause(Node);
cond_expr ->
revert_cond_expr(Node);
eof_marker ->
revert_eof_marker(Node);
error_marker ->
revert_error_marker(Node);
float ->
revert_float(Node);
fun_expr ->
revert_fun_expr(Node);
function ->
revert_function(Node);
generator ->
revert_generator(Node);
if_expr ->
revert_if_expr(Node);
implicit_fun ->
revert_implicit_fun(Node);
infix_expr ->
revert_infix_expr(Node);
integer ->
revert_integer(Node);
list ->
revert_list(Node);
list_comp ->
revert_list_comp(Node);
match_expr ->
revert_match_expr(Node);
module_qualifier ->
revert_module_qualifier(Node);
nil ->
revert_nil(Node);
parentheses ->
revert_parentheses(Node);
prefix_expr ->
revert_prefix_expr(Node);
qualified_name ->
revert_qualified_name(Node);
query_expr ->
revert_query_expr(Node);
receive_expr ->
revert_receive_expr(Node);
record_access ->
revert_record_access(Node);
record_expr ->
revert_record_expr(Node);
record_index_expr ->
revert_record_index_expr(Node);
rule ->
revert_rule(Node);
string ->
revert_string(Node);
try_expr ->
revert_try_expr(Node);
tuple ->
revert_tuple(Node);
underscore ->
revert_underscore(Node);
variable ->
revert_variable(Node);
warning_marker ->
revert_warning_marker(Node);
_ ->
%% Non-revertible new-form node
Node
end.
%% =====================================================================
%% @spec revert_forms(Forms) -> [erl_parse()]
%%
%% Forms = syntaxTree() | [syntaxTree()]
%%
%% @doc Reverts a sequence of Erlang source code forms. The sequence can
%% be given either as a <code>form_list</code> syntax tree (possibly
%% nested), or as a list of "program form" syntax trees. If successful,
%% the corresponding flat list of <code>erl_parse</code>-compatible
%% syntax trees is returned (cf. <code>revert/1</code>). If some program
%% form could not be reverted, <code>{error, Form}</code> is thrown.
%% Standalone comments in the form sequence are discarded.
%%
%% @see revert/1
%% @see form_list/1
%% @see is_form/1
revert_forms(L) when is_list(L) ->
revert_forms(form_list(L));
revert_forms(T) ->
case type(T) of
form_list ->
T1 = flatten_form_list(T),
case catch {ok, revert_forms_1(form_list_elements(T1))} of
{ok, Fs} ->
Fs;
{error, _} = Error ->
erlang:error(Error);
{'EXIT', R} ->
exit(R);
R ->
throw(R)
end;
_ ->
erlang:error({badarg, T})
end.
revert_forms_1([T | Ts]) ->
case type(T) of
comment ->
revert_forms_1(Ts);
_ ->
T1 = revert(T),
case is_tree(T1) of
true ->
throw({error, T1});
false ->
[T1 | revert_forms_1(Ts)]
end
end;
revert_forms_1([]) ->
[].
%% =====================================================================
%% @spec subtrees(Node::syntaxTree()) -> [[syntaxTree()]]
%%
%% @doc Returns the grouped list of all subtrees of a syntax tree. If
%% <code>Node</code> is a leaf node (cf. <code>is_leaf/1</code>), this
%% is the empty list, otherwise the result is always a nonempty list,
%% containing the lists of subtrees of <code>Node</code>, in
%% left-to-right order as they occur in the printed program text, and
%% grouped by category. Often, each group contains only a single
%% subtree.
%%
%% <p>Depending on the type of <code>Node</code>, the size of some
%% groups may be variable (e.g., the group consisting of all the
%% elements of a tuple), while others always contain the same number of
%% elements - usually exactly one (e.g., the group containing the
%% argument expression of a case-expression). Note, however, that the
%% exact structure of the returned list (for a given node type) should
%% in general not be depended upon, since it might be subject to change
%% without notice.</p>
%%
%% <p>The function <code>subtrees/1</code> and the constructor functions
%% <code>make_tree/2</code> and <code>update_tree/2</code> can be a
%% great help if one wants to traverse a syntax tree, visiting all its
%% subtrees, but treat nodes of the tree in a uniform way in most or all
%% cases. Using these functions makes this simple, and also assures that
%% your code is not overly sensitive to extensions of the syntax tree
%% data type, because any node types not explicitly handled by your code
%% can be left to a default case.</p>
%%
%% <p>For example:
%% <pre>
%% postorder(F, Tree) ->
%% F(case subtrees(Tree) of
%% [] -> Tree;
%% List -> update_tree(Tree,
%% [[postorder(F, Subtree)
%% || Subtree <- Group]
%% || Group <- List])
%% end).
%% </pre>
%% maps the function <code>F</code> on <code>Tree</code> and all its
%% subtrees, doing a post-order traversal of the syntax tree. (Note the
%% use of <code>update_tree/2</code> to preserve node attributes.) For a
%% simple function like:
%% <pre>
%% f(Node) ->
%% case type(Node) of
%% atom -> atom("a_" ++ atom_name(Node));
%% _ -> Node
%% end.
%% </pre>
%% the call <code>postorder(fun f/1, Tree)</code> will yield a new
%% representation of <code>Tree</code> in which all atom names have been
%% extended with the prefix "a_", but nothing else (including comments,
%% annotations and line numbers) has been changed.</p>
%%
%% @see make_tree/2
%% @see type/1
%% @see is_leaf/1
%% @see copy_attrs/2
subtrees(T) ->
case is_leaf(T) of
true ->
[];
false ->
case type(T) of
application ->
[[application_operator(T)],
application_arguments(T)];
arity_qualifier ->
[[arity_qualifier_body(T)],
[arity_qualifier_argument(T)]];
attribute ->
case attribute_arguments(T) of
none ->
[[attribute_name(T)]];
As ->
[[attribute_name(T)], As]
end;
binary ->
[binary_fields(T)];
binary_comp ->
[[binary_comp_template(T)], binary_comp_body(T)];
binary_field ->
case binary_field_types(T) of
[] ->
[[binary_field_body(T)]];
Ts ->
[[binary_field_body(T)],
Ts]
end;
binary_generator ->
[[binary_generator_pattern(T)],
[binary_generator_body(T)]];
block_expr ->
[block_expr_body(T)];
case_expr ->
[[case_expr_argument(T)],
case_expr_clauses(T)];
catch_expr ->
[[catch_expr_body(T)]];
class_qualifier ->
[[class_qualifier_argument(T)],
[class_qualifier_body(T)]];
clause ->
case clause_guard(T) of
none ->
[clause_patterns(T), clause_body(T)];
G ->
[clause_patterns(T), [G],
clause_body(T)]
end;
cond_expr ->
[cond_expr_clauses(T)];
conjunction ->
[conjunction_body(T)];
disjunction ->
[disjunction_body(T)];
form_list ->
[form_list_elements(T)];
fun_expr ->
[fun_expr_clauses(T)];
function ->
[[function_name(T)], function_clauses(T)];
generator ->
[[generator_pattern(T)], [generator_body(T)]];
if_expr ->
[if_expr_clauses(T)];
implicit_fun ->
[[implicit_fun_name(T)]];
infix_expr ->
[[infix_expr_left(T)],
[infix_expr_operator(T)],
[infix_expr_right(T)]];
list ->
case list_suffix(T) of
none ->
[list_prefix(T)];
S ->
[list_prefix(T), [S]]
end;
list_comp ->
[[list_comp_template(T)], list_comp_body(T)];
macro ->
case macro_arguments(T) of
none ->
[[macro_name(T)]];
As ->
[[macro_name(T)], As]
end;
match_expr ->
[[match_expr_pattern(T)],
[match_expr_body(T)]];
module_qualifier ->
[[module_qualifier_argument(T)],
[module_qualifier_body(T)]];
parentheses ->
[[parentheses_body(T)]];
prefix_expr ->
[[prefix_expr_operator(T)],
[prefix_expr_argument(T)]];
qualified_name ->
[qualified_name_segments(T)];
query_expr ->
[[query_expr_body(T)]];
receive_expr ->
case receive_expr_timeout(T) of
none ->
[receive_expr_clauses(T)];
E ->
[receive_expr_clauses(T),
[E],
receive_expr_action(T)]
end;
record_access ->
case record_access_type(T) of
none ->
[[record_access_argument(T)],
[record_access_field(T)]];
R ->
[[record_access_argument(T)],
[R],
[record_access_field(T)]]
end;
record_expr ->
case record_expr_argument(T) of
none ->
[[record_expr_type(T)],
record_expr_fields(T)];
V ->
[[V],
[record_expr_type(T)],
record_expr_fields(T)]
end;
record_field ->
case record_field_value(T) of
none ->
[[record_field_name(T)]];
V ->
[[record_field_name(T)], [V]]
end;
record_index_expr ->
[[record_index_expr_type(T)],
[record_index_expr_field(T)]];
rule ->
[[rule_name(T)], rule_clauses(T)];
size_qualifier ->
[[size_qualifier_body(T)],
[size_qualifier_argument(T)]];
try_expr ->
[try_expr_body(T),
try_expr_clauses(T),
try_expr_handlers(T),
try_expr_after(T)];
tuple ->
[tuple_elements(T)]
end
end.
%% =====================================================================
%% @spec update_tree(Node::syntaxTree(), Groups::[[syntaxTree()]]) ->
%% syntaxTree()
%%
%% @doc Creates a syntax tree with the same type and attributes as the
%% given tree. This is equivalent to <code>copy_attrs(Node,
%% make_tree(type(Node), Groups))</code>.
%%
%% @see make_tree/2
%% @see copy_attrs/2
%% @see type/1
update_tree(Node, Groups) ->
copy_attrs(Node, make_tree(type(Node), Groups)).
%% =====================================================================
%% @spec make_tree(Type::atom(), Groups::[[syntaxTree()]]) ->
%% syntaxTree()
%%
%% @doc Creates a syntax tree with the given type and subtrees.
%% <code>Type</code> must be a node type name (cf. <code>type/1</code>)
%% that does not denote a leaf node type (cf. <code>is_leaf/1</code>).
%% <code>Groups</code> must be a <em>nonempty</em> list of groups of
%% syntax trees, representing the subtrees of a node of the given type,
%% in left-to-right order as they would occur in the printed program
%% text, grouped by category as done by <code>subtrees/1</code>.
%%
%% <p>The result of <code>copy_attrs(Node, make_tree(type(Node),
%% subtrees(Node)))</code> (cf. <code>update_tree/2</code>) represents
%% the same source code text as the original <code>Node</code>, assuming
%% that <code>subtrees(Node)</code> yields a nonempty list. However, it
%% does not necessarily have the same data representation as
%% <code>Node</code>.</p>
%%
%% @see update_tree/2
%% @see subtrees/1
%% @see type/1
%% @see is_leaf/1
%% @see copy_attrs/2
make_tree(application, [[F], A]) -> application(F, A);
make_tree(arity_qualifier, [[N], [A]]) -> arity_qualifier(N, A);
make_tree(attribute, [[N]]) -> attribute(N);
make_tree(attribute, [[N], A]) -> attribute(N, A);
make_tree(binary, [Fs]) -> binary(Fs);
make_tree(binary_comp, [[T], B]) -> binary_comp(T, B);
make_tree(binary_field, [[B]]) -> binary_field(B);
make_tree(binary_field, [[B], Ts]) -> binary_field(B, Ts);
make_tree(binary_generator, [[P], [E]]) -> binary_generator(P, E);
make_tree(block_expr, [B]) -> block_expr(B);
make_tree(case_expr, [[A], C]) -> case_expr(A, C);
make_tree(catch_expr, [[B]]) -> catch_expr(B);
make_tree(class_qualifier, [[A], [B]]) -> class_qualifier(A, B);
make_tree(clause, [P, B]) -> clause(P, none, B);
make_tree(clause, [P, [G], B]) -> clause(P, G, B);
make_tree(cond_expr, [C]) -> cond_expr(C);
make_tree(conjunction, [E]) -> conjunction(E);
make_tree(disjunction, [E]) -> disjunction(E);
make_tree(form_list, [E]) -> form_list(E);
make_tree(fun_expr, [C]) -> fun_expr(C);
make_tree(function, [[N], C]) -> function(N, C);
make_tree(generator, [[P], [E]]) -> generator(P, E);
make_tree(if_expr, [C]) -> if_expr(C);
make_tree(implicit_fun, [[N]]) -> implicit_fun(N);
make_tree(infix_expr, [[L], [F], [R]]) -> infix_expr(L, F, R);
make_tree(list, [P]) -> list(P);
make_tree(list, [P, [S]]) -> list(P, S);
make_tree(list_comp, [[T], B]) -> list_comp(T, B);
make_tree(macro, [[N]]) -> macro(N);
make_tree(macro, [[N], A]) -> macro(N, A);
make_tree(match_expr, [[P], [E]]) -> match_expr(P, E);
make_tree(module_qualifier, [[M], [N]]) -> module_qualifier(M, N);
make_tree(parentheses, [[E]]) -> parentheses(E);
make_tree(prefix_expr, [[F], [A]]) -> prefix_expr(F, A);
make_tree(qualified_name, [S]) -> qualified_name(S);
make_tree(query_expr, [[B]]) -> query_expr(B);
make_tree(receive_expr, [C]) -> receive_expr(C);
make_tree(receive_expr, [C, [E], A]) -> receive_expr(C, E, A);
make_tree(record_access, [[E], [F]]) ->
record_access(E, F);
make_tree(record_access, [[E], [T], [F]]) ->
record_access(E, T, F);
make_tree(record_expr, [[T], F]) -> record_expr(T, F);
make_tree(record_expr, [[E], [T], F]) -> record_expr(E, T, F);
make_tree(record_field, [[N]]) -> record_field(N);
make_tree(record_field, [[N], [E]]) -> record_field(N, E);
make_tree(record_index_expr, [[T], [F]]) ->
record_index_expr(T, F);
make_tree(rule, [[N], C]) -> rule(N, C);
make_tree(size_qualifier, [[N], [A]]) -> size_qualifier(N, A);
make_tree(try_expr, [B, C, H, A]) -> try_expr(B, C, H, A);
make_tree(tuple, [E]) -> tuple(E).
%% =====================================================================
%% @spec meta(Tree::syntaxTree()) -> syntaxTree()
%%
%% @doc Creates a meta-representation of a syntax tree. The result
%% represents an Erlang expression "<code><em>MetaTree</em></code>"
%% which, if evaluated, will yield a new syntax tree representing the
%% same source code text as <code>Tree</code> (although the actual data
%% representation may be different). The expression represented by
%% <code>MetaTree</code> is <em>implementation independent</em> with
%% regard to the data structures used by the abstract syntax tree
%% implementation. Comments attached to nodes of <code>Tree</code> will
%% be preserved, but other attributes are lost.
%%
%% <p>Any node in <code>Tree</code> whose node type is
%% <code>variable</code> (cf. <code>type/1</code>), and whose list of
%% annotations (cf. <code>get_ann/1</code>) contains the atom
%% <code>meta_var</code>, will remain unchanged in the resulting tree,
%% except that exactly one occurrence of <code>meta_var</code> is
%% removed from its annotation list.</p>
%%
%% <p>The main use of the function <code>meta/1</code> is to transform a
%% data structure <code>Tree</code>, which represents a piece of program
%% code, into a form that is <em>representation independent when
%% printed</em>. E.g., suppose <code>Tree</code> represents a variable
%% named "V". Then (assuming a function <code>print/1</code> for
%% printing syntax trees), evaluating <code>print(abstract(Tree))</code>
%% - simply using <code>abstract/1</code> to map the actual data
%% structure onto a syntax tree representation - would output a string
%% that might look something like "<code>{tree, variable, ..., "V",
%% ...}</code>", which is obviously dependent on the implementation of
%% the abstract syntax trees. This could e.g. be useful for caching a
%% syntax tree in a file. However, in some situations like in a program
%% generator generator (with two "generator"), it may be unacceptable.
%% Using <code>print(meta(Tree))</code> instead would output a
%% <em>representation independent</em> syntax tree generating
%% expression; in the above case, something like
%% "<code>erl_syntax:variable("V")</code>".</p>
%%
%% @see abstract/1
%% @see type/1
%% @see get_ann/1
meta(T) ->
%% First of all we check for metavariables:
case type(T) of
variable ->
case lists:member(meta_var, get_ann(T)) of
false ->
meta_precomment(T);
true ->
%% A meta-variable: remove the first found
%% `meta_var' annotation, but otherwise leave
%% the node unchanged.
set_ann(T, lists:delete(meta_var, get_ann(T)))
end;
_ ->
case has_comments(T) of
true ->
meta_precomment(T);
false ->
meta_1(T)
end
end.
meta_precomment(T) ->
case get_precomments(T) of
[] ->
meta_postcomment(T);
Cs ->
meta_call(set_precomments,
[meta_postcomment(T), list(meta_list(Cs))])
end.
meta_postcomment(T) ->
case get_postcomments(T) of
[] ->
meta_0(T);
Cs ->
meta_call(set_postcomments,
[meta_0(T), list(meta_list(Cs))])
end.
meta_0(T) ->
meta_1(remove_comments(T)).
meta_1(T) ->
%% First handle leaf nodes and other common cases, in order to
%% generate compact code.
case type(T) of
atom ->
meta_call(atom, [T]);
char ->
meta_call(char, [T]);
comment ->
meta_call(comment, [list([string(S)
|| S <- comment_text(T)])]);
eof_marker ->
meta_call(eof_marker, []);
error_marker ->
meta_call(error_marker,
[abstract(error_marker_info(T))]);
float ->
meta_call(float, [T]);
integer ->
meta_call(integer, [T]);
nil ->
meta_call(nil, []);
operator ->
meta_call(operator, [atom(operator_name(T))]);
string ->
meta_call(string, [T]);
text ->
meta_call(text, [string(text_string(T))]);
underscore ->
meta_call(underscore, []);
variable ->
meta_call(variable, [string(atom_to_list(variable_name(T)))]);
warning_marker ->
meta_call(warning_marker,
[abstract(warning_marker_info(T))]);
list ->
case list_suffix(T) of
none ->
meta_call(list,
[list(meta_list(list_prefix(T)))]);
S ->
meta_call(list,
[list(meta_list(list_prefix(T))),
meta(S)])
end;
tuple ->
meta_call(tuple,
[list(meta_list(tuple_elements(T)))]);
Type ->
%% All remaining cases are handled using `subtrees'
%% and `make_tree' to decompose and reassemble the
%% nodes. More cases could of course be handled
%% directly to get a more compact output, but I can't
%% be bothered right now.
meta_call(make_tree,
[abstract(Type),
meta_subtrees(subtrees(T))])
end.
meta_list([T | Ts]) ->
[meta(T) | meta_list(Ts)];
meta_list([]) ->
[].
meta_subtrees(Gs) ->
list([list([meta(T)
|| T <- G])
|| G <- Gs]).
meta_call(F, As) ->
application(atom(?MODULE), atom(F), As).
%% =====================================================================
%% Functions for abstraction of the syntax tree representation; may be
%% used externally, but not intended for the normal user.
%% =====================================================================
%% =====================================================================
%% @spec tree(Type) -> syntaxTree()
%% @equiv tree(Type, [])
tree(Type) ->
tree(Type, []).
%% =====================================================================
%% @spec tree(Type::atom(), Data::term()) -> syntaxTree()
%%
%% @doc <em>For special purposes only</em>. Creates an abstract syntax
%% tree node with type tag <code>Type</code> and associated data
%% <code>Data</code>.
%%
%% <p>This function and the related <code>is_tree/1</code> and
%% <code>data/1</code> provide a uniform way to extend the set of
%% <code>erl_parse</code> node types. The associated data is any term,
%% whose format may depend on the type tag.</p>
%%
%% <h4>Notes:</h4>
%% <ul>
%% <li>Any nodes created outside of this module must have type tags
%% distinct from those currently defined by this module; see
%% <code>type/1</code> for a complete list.</li>
%% <li>The type tag of a syntax tree node may also be used
%% as a primary tag by the <code>erl_parse</code> representation;
%% in that case, the selector functions for that node type
%% <em>must</em> handle both the abstract syntax tree and the
%% <code>erl_parse</code> form. The function <code>type(T)</code>
%% should return the correct type tag regardless of the
%% representation of <code>T</code>, so that the user sees no
%% difference between <code>erl_syntax</code> and
%% <code>erl_parse</code> nodes.</li>
%% </ul>
%% @see is_tree/1
%% @see data/1
%% @see type/1
tree(Type, Data) ->
#tree{type = Type, data = Data}.
%% =====================================================================
%% @spec is_tree(Tree::syntaxTree()) -> bool()
%%
%% @doc <em>For special purposes only</em>. Returns <code>true</code> if
%% <code>Tree</code> is an abstract syntax tree and <code>false</code>
%% otherwise.
%%
%% <p><em>Note</em>: this function yields <code>false</code> for all
%% "old-style" <code>erl_parse</code>-compatible "parse trees".</p>
%%
%% @see tree/2
is_tree(#tree{}) ->
true;
is_tree(_) ->
false.
%% =====================================================================
%% @spec data(Tree::syntaxTree()) -> term()
%%
%% @doc <em>For special purposes only</em>. Returns the associated data
%% of a syntax tree node. Evaluation fails with reason
%% <code>badarg</code> if <code>is_tree(Node)</code> does not yield
%% <code>true</code>.
%%
%% @see tree/2
data(#tree{data = D}) -> D;
data(T) -> erlang:error({badarg, T}).
%% =====================================================================
%% Primitives for backwards compatibility; for internal use only
%% =====================================================================
%% =====================================================================
%% @spec wrap(Node::erl_parse()) -> syntaxTree()
%%
%% @type erl_parse() = erl_parse:parse_tree(). The "parse tree"
%% representation built by the Erlang standard library parser
%% <code>erl_parse</code>. This is a subset of the
%% <a href="#type-syntaxTree"><code>syntaxTree</code></a> type.
%%
%% @doc Creates a wrapper structure around an <code>erl_parse</code>
%% "parse tree".
%%
%% <p>This function and the related <code>unwrap/1</code> and
%% <code>is_wrapper/1</code> provide a uniform way to attach arbitrary
%% information to an <code>erl_parse</code> tree. Some information about
%% the encapsuled tree may be cached in the wrapper, such as the node
%% type. All functions on syntax trees must behave so that the user sees
%% no difference between wrapped and non-wrapped <code>erl_parse</code>
%% trees. <em>Attaching a wrapper onto another wrapper structure is an
%% error</em>.</p>
wrap(Node) ->
%% We assume that Node is an old-school `erl_parse' tree.
#wrapper{type = type(Node), attr = #attr{pos = get_pos(Node)},
tree = Node}.
%% =====================================================================
%% @spec unwrap(Node::syntaxTree()) -> syntaxTree()
%%
%% @doc Removes any wrapper structure, if present. If <code>Node</code>
%% is a wrapper structure, this function returns the wrapped
%% <code>erl_parse</code> tree; otherwise it returns <code>Node</code>
%% itself.
unwrap(#wrapper{tree = Node}) -> Node;
unwrap(Node) -> Node. % This could also be a new-form node.
%% =====================================================================
%% @spec is_wrapper(Term::term()) -> bool()
%%
%% @doc Returns <code>true</code> if the argument is a wrapper
%% structure, otherwise <code>false</code>.
-ifndef(NO_UNUSED).
is_wrapper(#wrapper{}) ->
true;
is_wrapper(_) ->
false.
-endif.
%% =====================================================================
%% General utility functions for internal use
%% =====================================================================
is_printable(S) ->
io_lib:printable_list(S).
%% Support functions for transforming lists of function names
%% specified as `arity_qualifier' nodes.
unfold_function_names(Ns, Pos) ->
F = fun ({Atom, Arity}) ->
N = arity_qualifier(atom(Atom), integer(Arity)),
set_pos(N, Pos)
end,
[F(N) || N <- Ns].
fold_function_names(Ns) ->
[fold_function_name(N) || N <- Ns].
fold_function_name(N) ->
Name = arity_qualifier_body(N),
Arity = arity_qualifier_argument(N),
true = ((type(Name) =:= atom) and (type(Arity) =:= integer)),
{concrete(Name), concrete(Arity)}.
fold_variable_names(Vs) ->
[variable_name(V) || V <- Vs].
unfold_variable_names(Vs, Pos) ->
[set_pos(variable(V), Pos) || V <- Vs].
%% Support functions for qualified names ("foo.bar.baz",
%% "erl.lang.lists", etc.). The representation overlaps with the weird
%% "Mnesia query record access" operators. The '.' operator is left
%% associative, so folding should nest on the left.
is_qualified_name({record_field, _, L, R}) ->
is_qualified_name(L) andalso is_qualified_name(R);
is_qualified_name({atom, _, _}) -> true;
is_qualified_name(_) -> false.
unfold_qualified_name(Node) ->
lists:reverse(unfold_qualified_name(Node, [])).
unfold_qualified_name({record_field, _, L, R}, Ss) ->
unfold_qualified_name(R, unfold_qualified_name(L, Ss));
unfold_qualified_name(S, Ss) -> [S | Ss].
fold_qualified_name([S | Ss], Pos) ->
fold_qualified_name(Ss, Pos, {atom, Pos, atom_value(S)}).
fold_qualified_name([S | Ss], Pos, Ack) ->
fold_qualified_name(Ss, Pos, {record_field, Pos, Ack,
{atom, Pos, atom_value(S)}});
fold_qualified_name([], _Pos, Ack) ->
Ack.
%% Support functions for transforming lists of record field definitions.
%%
%% There is no unique representation for field definitions in the
%% standard form. There, they may only occur in the "fields" part of a
%% record expression or declaration, and are represented as
%% `{record_field, Pos, Name, Value}', or as `{record_field, Pos, Name}'
%% if the value part is left out. However, these cannot be distinguished
%% out of context from the representation of record field access
%% expressions (see `record_access').
fold_record_fields(Fs) ->
[fold_record_field(F) || F <- Fs].
fold_record_field(F) ->
Pos = get_pos(F),
Name = record_field_name(F),
case record_field_value(F) of
none ->
{record_field, Pos, Name};
Value ->
{record_field, Pos, Name, Value}
end.
unfold_record_fields(Fs) ->
[unfold_record_field(F) || F <- Fs].
unfold_record_field({typed_record_field, Field, _Type}) ->
unfold_record_field_1(Field);
unfold_record_field(Field) ->
unfold_record_field_1(Field).
unfold_record_field_1({record_field, Pos, Name}) ->
set_pos(record_field(Name), Pos);
unfold_record_field_1({record_field, Pos, Name, Value}) ->
set_pos(record_field(Name, Value), Pos).
fold_binary_field_types(Ts) ->
[fold_binary_field_type(T) || T <- Ts].
fold_binary_field_type(Node) ->
case type(Node) of
size_qualifier ->
{concrete(size_qualifier_body(Node)),
concrete(size_qualifier_argument(Node))};
_ ->
concrete(Node)
end.
unfold_binary_field_types(Ts, Pos) ->
[unfold_binary_field_type(T, Pos) || T <- Ts].
unfold_binary_field_type({Type, Size}, Pos) ->
set_pos(size_qualifier(atom(Type), integer(Size)), Pos);
unfold_binary_field_type(Type, Pos) ->
set_pos(atom(Type), Pos).
%% =====================================================================
