%% ===================================================================== %% 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 %% %% @copyright 1997-2006 Richard Carlsson %% @author Richard Carlsson %% @end %% ===================================================================== %% @doc Pretty printing of abstract Erlang syntax trees. %% %% This module is a front end to the pretty-printing library module %% `prettypr', for text formatting of abstract syntax trees defined by %% the module `erl_syntax'. -module(erl_prettypr). -export([format/1, format/2, best/1, best/2, layout/1, layout/2, get_ctxt_precedence/1, set_ctxt_precedence/2, get_ctxt_paperwidth/1, set_ctxt_paperwidth/2, get_ctxt_linewidth/1, set_ctxt_linewidth/2, get_ctxt_hook/1, set_ctxt_hook/2, get_ctxt_user/1, set_ctxt_user/2]). -import(prettypr, [text/1, nest/2, above/2, beside/2, sep/1, par/1, par/2, floating/3, floating/1, break/1, follow/2, follow/3, empty/0]). -import(erl_parse, [preop_prec/1, inop_prec/1, func_prec/0, max_prec/0]). -define(PADDING, 2). -define(PAPER, 80). -define(RIBBON, 56). -define(NOUSER, undefined). -define(NOHOOK, none). -type hook() :: 'none' | fun((erl_syntax:syntaxTree(), _, _) -> prettypr:document()). -type clause_t() :: 'case_expr' | 'cond_expr' | 'fun_expr' | 'if_expr' | 'receive_expr' | 'try_expr' | {'function', prettypr:document()} | {'rule', prettypr:document()}. -record(ctxt, {prec = 0 :: integer(), sub_indent = 2 :: non_neg_integer(), break_indent = 4 :: non_neg_integer(), clause = undefined :: clause_t() | 'undefined', hook = ?NOHOOK :: hook(), paper = ?PAPER :: integer(), ribbon = ?RIBBON :: integer(), user = ?NOUSER :: term(), encoding = epp:default_encoding() :: epp:source_encoding()}). -type context() :: #ctxt{}. %% ===================================================================== %% The following functions examine and modify contexts: %% @spec (context()) -> integer() %% @doc Returns the operator precedence field of the prettyprinter %% context. %% %% @see set_ctxt_precedence/2 -spec get_ctxt_precedence(context()) -> integer(). get_ctxt_precedence(Ctxt) -> Ctxt#ctxt.prec. %% @spec (context(), integer()) -> context() %% %% @doc Updates the operator precedence field of the prettyprinter %% context. See the {@link //stdlib/erl_parse} module for operator precedences. %% %% @see //stdlib/erl_parse %% @see get_ctxt_precedence/1 -spec set_ctxt_precedence(context(), integer()) -> context(). set_ctxt_precedence(Ctxt, Prec) -> set_prec(Ctxt, Prec). set_prec(Ctxt, Prec) -> Ctxt#ctxt{prec = Prec}. % used internally reset_prec(Ctxt) -> set_prec(Ctxt, 0). % used internally %% @spec (context()) -> integer() %% @doc Returns the paper widh field of the prettyprinter context. %% @see set_ctxt_paperwidth/2 -spec get_ctxt_paperwidth(context()) -> integer(). get_ctxt_paperwidth(Ctxt) -> Ctxt#ctxt.paper. %% @spec (context(), integer()) -> context() %% %% @doc Updates the paper widh field of the prettyprinter context. %% %% Note: changing this value (and passing the resulting context to a %% continuation function) does not affect the normal formatting, but may %% affect user-defined behaviour in hook functions. %% %% @see get_ctxt_paperwidth/1 -spec set_ctxt_paperwidth(context(), integer()) -> context(). set_ctxt_paperwidth(Ctxt, W) -> Ctxt#ctxt{paper = W}. %% @spec (context()) -> integer() %% @doc Returns the line widh field of the prettyprinter context. %% @see set_ctxt_linewidth/2 -spec get_ctxt_linewidth(context()) -> integer(). get_ctxt_linewidth(Ctxt) -> Ctxt#ctxt.ribbon. %% @spec (context(), integer()) -> context() %% %% @doc Updates the line widh field of the prettyprinter context. %% %% Note: changing this value (and passing the resulting context to a %% continuation function) does not affect the normal formatting, but may %% affect user-defined behaviour in hook functions. %% %% @see get_ctxt_linewidth/1 -spec set_ctxt_linewidth(context(), integer()) -> context(). set_ctxt_linewidth(Ctxt, W) -> Ctxt#ctxt{ribbon = W}. %% @spec (context()) -> hook() %% @doc Returns the hook function field of the prettyprinter context. %% @see set_ctxt_hook/2 -spec get_ctxt_hook(context()) -> hook(). get_ctxt_hook(Ctxt) -> Ctxt#ctxt.hook. %% @spec (context(), hook()) -> context() %% @doc Updates the hook function field of the prettyprinter context. %% @see get_ctxt_hook/1 -spec set_ctxt_hook(context(), hook()) -> context(). set_ctxt_hook(Ctxt, Hook) -> Ctxt#ctxt{hook = Hook}. %% @spec (context()) -> term() %% @doc Returns the user data field of the prettyprinter context. %% @see set_ctxt_user/2 -spec get_ctxt_user(context()) -> term(). get_ctxt_user(Ctxt) -> Ctxt#ctxt.user. %% @spec (context(), term()) -> context() %% @doc Updates the user data field of the prettyprinter context. %% @see get_ctxt_user/1 -spec set_ctxt_user(context(), term()) -> context(). set_ctxt_user(Ctxt, X) -> Ctxt#ctxt{user = X}. %% ===================================================================== %% @spec format(Tree::syntaxTree()) -> string() %% @equiv format(Tree, []) -spec format(erl_syntax:syntaxTree()) -> string(). format(Node) -> format(Node, []). %% ===================================================================== %% @spec format(Tree::syntaxTree(), Options::[term()]) -> string() %% syntaxTree() = erl_syntax:syntaxTree() %% %% @type hook() = (syntaxTree(), context(), Continuation) -> document() %% Continuation = (syntaxTree(), context()) -> document(). %% %% A call-back function for user-controlled formatting. See {@link %% format/2}. %% %% @type context(). A representation of the current context of the %% pretty-printer. Can be accessed in hook functions. %% %% @doc Prettyprint-formats an abstract Erlang syntax tree as text. For %% example, if you have a `.beam' file that has been compiled with %% `debug_info', the following should print the source code for the %% module (as it looks in the debug info representation): %% ```{ok,{_,[{abstract_code,{_,AC}}]}} = %% beam_lib:chunks("myfile.beam",[abstract_code]), %% io:put_chars(erl_prettypr:format(erl_syntax:form_list(AC))) %% ''' %% %% Available options: %%
%%
{hook, none | {@link hook()}}
%%
Unless the value is `none', the given function is called %% for each node whose list of annotations is not empty; see below %% for details. The default value is `none'.
%% %%
{paper, integer()}
%%
Specifies the preferred maximum number of characters on any %% line, including indentation. The default value is 80.
%% %%
{ribbon, integer()}
%%
Specifies the preferred maximum number of characters on any %% line, not counting indentation. The default value is 65.
%% %%
{user, term()}
%%
User-specific data for use in hook functions. The default %% value is `undefined'.
%%
{encoding, epp:source_encoding()}
%%
Specifies the encoding of the generated file.
%%
%% %% A hook function (cf. the {@link hook()} type) is passed the current %% syntax tree node, the context, and a continuation. The context can be %% examined and manipulated by functions such as `get_ctxt_user/1' and %% `set_ctxt_user/2'. The hook must return a "document" data structure %% (see {@link layout/2} and {@link best/2}); this may be constructed in %% part or in whole by applying the continuation function. For example, %% the following is a trivial hook: %% ``` %% fun (Node, Ctxt, Cont) -> Cont(Node, Ctxt) end %% ''' %% which yields the same result as if no hook was given. %% The following, however: %% ``` %% fun (Node, Ctxt, Cont) -> %% Doc = Cont(Node, Ctxt), %% prettypr:beside(prettypr:text(""), %% prettypr:beside(Doc, %% prettypr:text(""))) %% end %% ''' %% will place the text of any annotated node (regardless of the %% annotation data) between HTML "boldface begin" and "boldface end" %% tags. %% %% @see erl_syntax %% @see format/1 %% @see layout/2 %% @see best/2 %% @see get_ctxt_user/1 %% @see set_ctxt_user/2 -spec format(erl_syntax:syntaxTree(), [term()]) -> string(). format(Node, Options) -> W = proplists:get_value(paper, Options, ?PAPER), L = proplists:get_value(ribbon, Options, ?RIBBON), prettypr:format(layout(Node, Options), W, L). %% ===================================================================== %% @spec best(Tree::syntaxTree()) -> empty | document() %% @equiv best(Tree, []) -spec best(erl_syntax:syntaxTree()) -> 'empty' | prettypr:document(). best(Node) -> best(Node, []). %% ===================================================================== %% @spec best(Tree::syntaxTree(), Options::[term()]) -> %% empty | document() %% %% @doc Creates a fixed "best" abstract layout for a syntax tree. This %% is similar to the `layout/2' function, except that here, the final %% layout has been selected with respect to the given options. The atom %% `empty' is returned if no such layout could be produced. For %% information on the options, see the `format/2' function. %% %% @see best/1 %% @see layout/2 %% @see format/2 %% @see prettypr:best/3 -spec best(erl_syntax:syntaxTree(), [term()]) -> 'empty' | prettypr:document(). best(Node, Options) -> W = proplists:get_value(paper, Options, ?PAPER), L = proplists:get_value(ribbon, Options, ?RIBBON), prettypr:best(layout(Node, Options), W, L). %% ===================================================================== %% @spec layout(Tree::syntaxTree()) -> document() %% @equiv layout(Tree, []) -spec layout(erl_syntax:syntaxTree()) -> prettypr:document(). layout(Node) -> layout(Node, []). %% ===================================================================== %% @spec layout(Tree::syntaxTree(), Options::[term()]) -> document() %% document() = prettypr:document() %% %% @doc Creates an abstract document layout for a syntax tree. The %% result represents a set of possible layouts (cf. module `prettypr'). %% For information on the options, see {@link format/2}; note, however, %% that the `paper' and `ribbon' options are ignored by this function. %% %% This function provides a low-level interface to the pretty printer, %% returning a flexible representation of possible layouts, independent %% of the paper width eventually to be used for formatting. This can be %% included as part of another document and/or further processed %% directly by the functions in the `prettypr' module, or used in a hook %% function (see `format/2' for details). %% %% @see prettypr %% @see format/2 %% @see layout/1 -spec layout(erl_syntax:syntaxTree(), [term()]) -> prettypr:document(). layout(Node, Options) -> lay(Node, #ctxt{hook = proplists:get_value(hook, Options, ?NOHOOK), paper = proplists:get_value(paper, Options, ?PAPER), ribbon = proplists:get_value(ribbon, Options, ?RIBBON), user = proplists:get_value(user, Options), encoding = proplists:get_value(encoding, Options, epp:default_encoding())}). lay(Node, Ctxt) -> case erl_syntax:get_ann(Node) of [] -> %% Hooks are not called if there are no annotations. lay_1(Node, Ctxt); _As -> case Ctxt#ctxt.hook of ?NOHOOK -> lay_1(Node, Ctxt); Hook -> Hook(Node, Ctxt, fun lay_1/2) end end. %% This handles attached comments: lay_1(Node, Ctxt) -> case erl_syntax:has_comments(Node) of true -> D1 = lay_2(Node, Ctxt), D2 = lay_postcomments(erl_syntax:get_postcomments(Node), D1), lay_precomments(erl_syntax:get_precomments(Node), D2); false -> lay_2(Node, Ctxt) end. %% For pre-comments, all padding is ignored. lay_precomments([], D) -> D; lay_precomments(Cs, D) -> above(floating(break(stack_comments(Cs, false)), -1, -1), D). %% For postcomments, individual padding is added. lay_postcomments([], D) -> D; lay_postcomments(Cs, D) -> beside(D, floating(break(stack_comments(Cs, true)), 1, 0)). %% Format (including padding, if `Pad' is `true', otherwise not) %% and stack the listed comments above each other. stack_comments([C | Cs], Pad) -> D = stack_comment_lines(erl_syntax:comment_text(C)), D1 = case Pad of true -> P = case erl_syntax:comment_padding(C) of none -> ?PADDING; P1 -> P1 end, beside(text(spaces(P)), D); false -> D end, case Cs of [] -> D1; % done _ -> above(D1, stack_comments(Cs, Pad)) end. %% Stack lines of text above each other and prefix each string in %% the list with a single `%' character. stack_comment_lines([S | Ss]) -> D = text(add_comment_prefix(S)), case Ss of [] -> D; _ -> above(D, stack_comment_lines(Ss)) end; stack_comment_lines([]) -> empty(). add_comment_prefix(S) -> [$% | S]. %% This part ignores annotations and comments: lay_2(Node, Ctxt) -> case erl_syntax:type(Node) of %% We list literals and other common cases first. variable -> text(erl_syntax:variable_literal(Node)); atom -> text(erl_syntax:atom_literal(Node)); integer -> text(erl_syntax:integer_literal(Node)); float -> text(tidy_float(erl_syntax:float_literal(Node))); char -> text(erl_syntax:char_literal(Node, Ctxt#ctxt.encoding)); string -> lay_string(erl_syntax:string_literal(Node, Ctxt#ctxt.encoding), Ctxt); nil -> text("[]"); tuple -> Es = seq(erl_syntax:tuple_elements(Node), floating(text(",")), reset_prec(Ctxt), fun lay/2), beside(floating(text("{")), beside(par(Es), floating(text("}")))); list -> Ctxt1 = reset_prec(Ctxt), Node1 = erl_syntax:compact_list(Node), D1 = par(seq(erl_syntax:list_prefix(Node1), floating(text(",")), Ctxt1, fun lay/2)), D = case erl_syntax:list_suffix(Node1) of none -> beside(D1, floating(text("]"))); S -> follow(D1, beside( floating(text("| ")), beside(lay(S, Ctxt1), floating(text("]"))))) end, beside(floating(text("[")), D); operator -> floating(text(erl_syntax:operator_literal(Node))); infix_expr -> Operator = erl_syntax:infix_expr_operator(Node), {PrecL, Prec, PrecR} = case erl_syntax:type(Operator) of operator -> inop_prec( erl_syntax:operator_name(Operator)); _ -> {0, 0, 0} end, D1 = lay(erl_syntax:infix_expr_left(Node), set_prec(Ctxt, PrecL)), D2 = lay(Operator, reset_prec(Ctxt)), D3 = lay(erl_syntax:infix_expr_right(Node), set_prec(Ctxt, PrecR)), D4 = par([D1, D2, D3], Ctxt#ctxt.sub_indent), maybe_parentheses(D4, Prec, Ctxt); prefix_expr -> Operator = erl_syntax:prefix_expr_operator(Node), {{Prec, PrecR}, Name} = case erl_syntax:type(Operator) of operator -> N = erl_syntax:operator_name(Operator), {preop_prec(N), N}; _ -> {{0, 0}, any} end, D1 = lay(Operator, reset_prec(Ctxt)), D2 = lay(erl_syntax:prefix_expr_argument(Node), set_prec(Ctxt, PrecR)), D3 = case Name of '+' -> beside(D1, D2); '-' -> beside(D1, D2); _ -> par([D1, D2], Ctxt#ctxt.sub_indent) end, maybe_parentheses(D3, Prec, Ctxt); application -> {PrecL, Prec} = func_prec(), D = lay(erl_syntax:application_operator(Node), set_prec(Ctxt, PrecL)), As = seq(erl_syntax:application_arguments(Node), floating(text(",")), reset_prec(Ctxt), fun lay/2), %% D1 = beside(D, beside(text("("), %% beside(par(As), %% floating(text(")"))))), D1 = beside(D, beside(text("("), beside(par(As), floating(text(")"))))), maybe_parentheses(D1, Prec, Ctxt); match_expr -> {PrecL, Prec, PrecR} = inop_prec('='), D1 = lay(erl_syntax:match_expr_pattern(Node), set_prec(Ctxt, PrecL)), D2 = lay(erl_syntax:match_expr_body(Node), set_prec(Ctxt, PrecR)), D3 = follow(beside(D1, floating(text(" ="))), D2, Ctxt#ctxt.break_indent), maybe_parentheses(D3, Prec, Ctxt); underscore -> text("_"); clause -> %% The style used for a clause depends on its context Ctxt1 = (reset_prec(Ctxt))#ctxt{clause = undefined}, D1 = par(seq(erl_syntax:clause_patterns(Node), floating(text(",")), Ctxt1, fun lay/2)), D2 = case erl_syntax:clause_guard(Node) of none -> none; G -> lay(G, Ctxt1) end, D3 = sep(seq(erl_syntax:clause_body(Node), floating(text(",")), Ctxt1, fun lay/2)), case Ctxt#ctxt.clause of fun_expr -> make_fun_clause(D1, D2, D3, Ctxt); {function, N} -> make_fun_clause(N, D1, D2, D3, Ctxt); if_expr -> make_if_clause(D1, D2, D3, Ctxt); cond_expr -> make_if_clause(D1, D2, D3, Ctxt); case_expr -> make_case_clause(D1, D2, D3, Ctxt); receive_expr -> make_case_clause(D1, D2, D3, Ctxt); try_expr -> make_case_clause(D1, D2, D3, Ctxt); {rule, N} -> make_rule_clause(N, D1, D2, D3, Ctxt); undefined -> %% If a clause is formatted out of context, we %% use a "fun-expression" clause style. make_fun_clause(D1, D2, D3, Ctxt) end; function -> %% Comments on the name itself will be repeated for each %% clause, but that seems to be the best way to handle it. Ctxt1 = reset_prec(Ctxt), D1 = lay(erl_syntax:function_name(Node), Ctxt1), D2 = lay_clauses(erl_syntax:function_clauses(Node), {function, D1}, Ctxt1), beside(D2, floating(text("."))); case_expr -> Ctxt1 = reset_prec(Ctxt), D1 = lay(erl_syntax:case_expr_argument(Node), Ctxt1), D2 = lay_clauses(erl_syntax:case_expr_clauses(Node), case_expr, Ctxt1), sep([par([follow(text("case"), D1, Ctxt1#ctxt.sub_indent), text("of")], Ctxt1#ctxt.break_indent), nest(Ctxt1#ctxt.sub_indent, D2), text("end")]); if_expr -> Ctxt1 = reset_prec(Ctxt), D = lay_clauses(erl_syntax:if_expr_clauses(Node), if_expr, Ctxt1), sep([follow(text("if"), D, Ctxt1#ctxt.sub_indent), text("end")]); cond_expr -> Ctxt1 = reset_prec(Ctxt), D = lay_clauses(erl_syntax:cond_expr_clauses(Node), cond_expr, Ctxt1), sep([text("cond"), nest(Ctxt1#ctxt.sub_indent, D), text("end")]); fun_expr -> Ctxt1 = reset_prec(Ctxt), D = lay_clauses(erl_syntax:fun_expr_clauses(Node), fun_expr, Ctxt1), sep([follow(text("fun"), D, Ctxt1#ctxt.sub_indent), text("end")]); named_fun_expr -> Ctxt1 = reset_prec(Ctxt), D1 = lay(erl_syntax:named_fun_expr_name(Node), Ctxt1), D = lay_clauses(erl_syntax:named_fun_expr_clauses(Node), {function,D1}, Ctxt1), sep([follow(text("fun"), D, Ctxt1#ctxt.sub_indent), text("end")]); module_qualifier -> {PrecL, _Prec, PrecR} = inop_prec(':'), D1 = lay(erl_syntax:module_qualifier_argument(Node), set_prec(Ctxt, PrecL)), D2 = lay(erl_syntax:module_qualifier_body(Node), set_prec(Ctxt, PrecR)), beside(D1, beside(text(":"), D2)); %% %% The rest is in alphabetical order %% arity_qualifier -> Ctxt1 = reset_prec(Ctxt), D1 = lay(erl_syntax:arity_qualifier_body(Node), Ctxt1), D2 = lay(erl_syntax:arity_qualifier_argument(Node), Ctxt1), beside(D1, beside(text("/"), D2)); attribute -> %% The attribute name and arguments are formatted similar to %% a function call, but prefixed with a "-" and followed by %% a period. If the arguments is `none', we only output the %% attribute name, without following parentheses. Ctxt1 = reset_prec(Ctxt), N = erl_syntax:attribute_name(Node), D = case erl_syntax:attribute_arguments(Node) of none -> lay(N, Ctxt1); Args -> As = seq(Args, floating(text(",")), Ctxt1, fun lay/2), beside(lay(N, Ctxt1), beside(text("("), beside(par(As), floating(text(")"))))) end, beside(floating(text("-")), beside(D, floating(text(".")))); binary -> Ctxt1 = reset_prec(Ctxt), Es = seq(erl_syntax:binary_fields(Node), floating(text(",")), Ctxt1, fun lay/2), beside(floating(text("<<")), beside(par(Es), floating(text(">>")))); binary_field -> Ctxt1 = set_prec(Ctxt, max_prec()), D1 = lay(erl_syntax:binary_field_body(Node), Ctxt1), D2 = case erl_syntax:binary_field_types(Node) of [] -> empty(); Ts -> beside(floating(text("/")), lay_bit_types(Ts, Ctxt1)) end, beside(D1, D2); block_expr -> Ctxt1 = reset_prec(Ctxt), Es = seq(erl_syntax:block_expr_body(Node), floating(text(",")), Ctxt1, fun lay/2), sep([text("begin"), nest(Ctxt1#ctxt.sub_indent, sep(Es)), text("end")]); catch_expr -> {Prec, PrecR} = preop_prec('catch'), D = lay(erl_syntax:catch_expr_body(Node), set_prec(Ctxt, PrecR)), D1 = follow(text("catch"), D, Ctxt#ctxt.sub_indent), maybe_parentheses(D1, Prec, Ctxt); class_qualifier -> Ctxt1 = set_prec(Ctxt, max_prec()), D1 = lay(erl_syntax:class_qualifier_argument(Node), Ctxt1), D2 = lay(erl_syntax:class_qualifier_body(Node), Ctxt1), beside(D1, beside(text(":"), D2)); comment -> D = stack_comment_lines( erl_syntax:comment_text(Node)), %% Default padding for standalone comments is empty. case erl_syntax:comment_padding(Node) of none -> floating(break(D)); P -> floating(break(beside(text(spaces(P)), D))) end; conjunction -> par(seq(erl_syntax:conjunction_body(Node), floating(text(",")), reset_prec(Ctxt), fun lay/2)); disjunction -> %% For clarity, we don't paragraph-format %% disjunctions; only conjunctions (see above). sep(seq(erl_syntax:disjunction_body(Node), floating(text(";")), reset_prec(Ctxt), fun lay/2)); error_marker -> E = erl_syntax:error_marker_info(Node), beside(text("** "), beside(lay_error_info(E, reset_prec(Ctxt)), text(" **"))); eof_marker -> empty(); form_list -> Es = seq(erl_syntax:form_list_elements(Node), none, reset_prec(Ctxt), fun lay/2), vertical_sep(text(""), Es); generator -> Ctxt1 = reset_prec(Ctxt), D1 = lay(erl_syntax:generator_pattern(Node), Ctxt1), D2 = lay(erl_syntax:generator_body(Node), Ctxt1), par([D1, beside(text("<- "), D2)], Ctxt1#ctxt.break_indent); binary_generator -> Ctxt1 = reset_prec(Ctxt), D1 = lay(erl_syntax:binary_generator_pattern(Node), Ctxt1), D2 = lay(erl_syntax:binary_generator_body(Node), Ctxt1), par([D1, beside(text("<= "), D2)], Ctxt1#ctxt.break_indent); implicit_fun -> D = lay(erl_syntax:implicit_fun_name(Node), reset_prec(Ctxt)), beside(floating(text("fun ")), D); list_comp -> Ctxt1 = reset_prec(Ctxt), D1 = lay(erl_syntax:list_comp_template(Node), Ctxt1), D2 = par(seq(erl_syntax:list_comp_body(Node), floating(text(",")), Ctxt1, fun lay/2)), beside(floating(text("[")), par([D1, beside(floating(text("|| ")), beside(D2, floating(text("]"))))])); binary_comp -> Ctxt1 = reset_prec(Ctxt), D1 = lay(erl_syntax:binary_comp_template(Node), Ctxt1), D2 = par(seq(erl_syntax:binary_comp_body(Node), floating(text(",")), Ctxt1, fun lay/2)), beside(floating(text("<< ")), par([D1, beside(floating(text(" || ")), beside(D2, floating(text(" >>"))))])); macro -> %% This is formatted similar to a normal function call, but %% prefixed with a "?". Ctxt1 = reset_prec(Ctxt), N = erl_syntax:macro_name(Node), D = case erl_syntax:macro_arguments(Node) of none-> lay(N, Ctxt1); Args -> As = seq(Args, floating(text(",")), set_prec(Ctxt1, max_prec()), fun lay/2), beside(lay(N, Ctxt1), beside(text("("), beside(par(As), floating(text(")"))))) end, D1 = beside(floating(text("?")), D), maybe_parentheses(D1, 0, Ctxt); % must be conservative! parentheses -> D = lay(erl_syntax:parentheses_body(Node), reset_prec(Ctxt)), lay_parentheses(D, Ctxt); receive_expr -> Ctxt1 = reset_prec(Ctxt), D1 = lay_clauses(erl_syntax:receive_expr_clauses(Node), receive_expr, Ctxt1), D2 = case erl_syntax:receive_expr_timeout(Node) of none -> D1; T -> D3 = lay(T, Ctxt1), A = erl_syntax:receive_expr_action(Node), D4 = sep(seq(A, floating(text(",")), Ctxt1, fun lay/2)), sep([D1, follow(floating(text("after")), append_clause_body(D4, D3, Ctxt1), Ctxt1#ctxt.sub_indent)]) end, sep([text("receive"), nest(Ctxt1#ctxt.sub_indent, D2), text("end")]); record_access -> {PrecL, Prec, PrecR} = inop_prec('#'), D1 = lay(erl_syntax:record_access_argument(Node), set_prec(Ctxt, PrecL)), D2 = beside( floating(text(".")), lay(erl_syntax:record_access_field(Node), set_prec(Ctxt, PrecR))), D3 = case erl_syntax:record_access_type(Node) of none -> D2; T -> beside(beside(floating(text("#")), lay(T, reset_prec(Ctxt))), D2) end, maybe_parentheses(beside(D1, D3), Prec, Ctxt); record_expr -> {PrecL, Prec, _} = inop_prec('#'), Ctxt1 = reset_prec(Ctxt), D1 = lay(erl_syntax:record_expr_type(Node), Ctxt1), D2 = par(seq(erl_syntax:record_expr_fields(Node), floating(text(",")), Ctxt1, fun lay/2)), D3 = beside(beside(floating(text("#")), D1), beside(text("{"), beside(D2, floating(text("}"))))), D4 = case erl_syntax:record_expr_argument(Node) of none -> D3; A -> beside(lay(A, set_prec(Ctxt, PrecL)), D3) end, maybe_parentheses(D4, Prec, Ctxt); record_field -> Ctxt1 = reset_prec(Ctxt), D1 = lay(erl_syntax:record_field_name(Node), Ctxt1), case erl_syntax:record_field_value(Node) of none -> D1; V -> par([D1, floating(text("=")), lay(V, Ctxt1)], Ctxt1#ctxt.break_indent) end; record_index_expr -> {Prec, PrecR} = preop_prec('#'), D1 = lay(erl_syntax:record_index_expr_type(Node), reset_prec(Ctxt)), D2 = lay(erl_syntax:record_index_expr_field(Node), set_prec(Ctxt, PrecR)), D3 = beside(beside(floating(text("#")), D1), beside(floating(text(".")), D2)), maybe_parentheses(D3, Prec, Ctxt); map_expr -> {PrecL, Prec, _} = inop_prec('#'), Ctxt1 = reset_prec(Ctxt), D1 = par(seq(erl_syntax:map_expr_fields(Node), floating(text(",")), Ctxt1, fun lay/2)), D2 = beside(text("#{"), beside(D1, floating(text("}")))), D3 = case erl_syntax:map_expr_argument(Node) of none -> D2; A -> beside(lay(A, set_prec(Ctxt, PrecL)), D2) end, maybe_parentheses(D3, Prec, Ctxt); map_field_assoc -> Ctxt1 = reset_prec(Ctxt), D1 = lay(erl_syntax:map_field_assoc_name(Node), Ctxt1), D2 = lay(erl_syntax:map_field_assoc_value(Node), Ctxt1), par([D1, floating(text("=>")), D2], Ctxt1#ctxt.break_indent); map_field_exact -> Ctxt1 = reset_prec(Ctxt), D1 = lay(erl_syntax:map_field_exact_name(Node), Ctxt1), D2 = lay(erl_syntax:map_field_exact_value(Node), Ctxt1), par([D1, floating(text(":=")), D2], Ctxt1#ctxt.break_indent); rule -> %% Comments on the name will be repeated; cf. %% `function'. Ctxt1 = reset_prec(Ctxt), D1 = lay(erl_syntax:rule_name(Node), Ctxt1), D2 = lay_clauses(erl_syntax:rule_clauses(Node), {rule, D1}, Ctxt1), beside(D2, floating(text("."))); size_qualifier -> Ctxt1 = set_prec(Ctxt, max_prec()), D1 = lay(erl_syntax:size_qualifier_body(Node), Ctxt1), D2 = lay(erl_syntax:size_qualifier_argument(Node), Ctxt1), beside(D1, beside(text(":"), D2)); text -> text(erl_syntax:text_string(Node)); try_expr -> Ctxt1 = reset_prec(Ctxt), D1 = sep(seq(erl_syntax:try_expr_body(Node), floating(text(",")), Ctxt1, fun lay/2)), Es0 = [text("end")], Es1 = case erl_syntax:try_expr_after(Node) of [] -> Es0; As -> D2 = sep(seq(As, floating(text(",")), Ctxt1, fun lay/2)), [text("after"), nest(Ctxt1#ctxt.sub_indent, D2) | Es0] end, Es2 = case erl_syntax:try_expr_handlers(Node) of [] -> Es1; Hs -> D3 = lay_clauses(Hs, try_expr, Ctxt1), [text("catch"), nest(Ctxt1#ctxt.sub_indent, D3) | Es1] end, Es3 = case erl_syntax:try_expr_clauses(Node) of [] -> Es2; Cs -> D4 = lay_clauses(Cs, try_expr, Ctxt1), [text("of"), nest(Ctxt1#ctxt.sub_indent, D4) | Es2] end, sep([par([follow(text("try"), D1, Ctxt1#ctxt.sub_indent), hd(Es3)]) | tl(Es3)]); warning_marker -> E = erl_syntax:warning_marker_info(Node), beside(text("%% WARNING: "), lay_error_info(E, reset_prec(Ctxt))) end. lay_parentheses(D, _Ctxt) -> beside(floating(text("(")), beside(D, floating(text(")")))). maybe_parentheses(D, Prec, Ctxt) -> case Ctxt#ctxt.prec of P when P > Prec -> lay_parentheses(D, Ctxt); _ -> D end. lay_string(S, Ctxt) -> %% S includes leading/trailing double-quote characters. The segment %% width is 2/3 of the ribbon width - this seems to work well. W = (Ctxt#ctxt.ribbon * 2) div 3, lay_string_1(S, length(S), W). lay_string_1(S, L, W) when L > W, W > 0 -> %% Note that L is the minimum, not the exact, printed length. case split_string(S, W - 1, L) of {_S1, ""} -> text(S); {S1, S2} -> above(text(S1 ++ "\""), lay_string_1([$" | S2], L - W + 1, W)) %" stupid emacs end; lay_string_1(S, _L, _W) -> text(S). split_string(Xs, N, L) -> split_string_1(Xs, N, L, []). %% We only split strings at whitespace, if possible. We must make sure %% we do not split an escape sequence. split_string_1([$\s | Xs], N, L, As) when N =< 0, L >= 5 -> {lists:reverse([$\s | As]), Xs}; split_string_1([$\t | Xs], N, L, As) when N =< 0, L >= 5 -> {lists:reverse([$t, $\\ | As]), Xs}; split_string_1([$\n | Xs], N, L, As) when N =< 0, L >= 5 -> {lists:reverse([$n, $\\ | As]), Xs}; split_string_1([$\\ | Xs], N, L, As) -> split_string_2(Xs, N - 1, L - 1, [$\\ | As]); split_string_1(Xs, N, L, As) when N =< -10, L >= 5 -> {lists:reverse(As), Xs}; split_string_1([X | Xs], N, L, As) -> split_string_1(Xs, N - 1, L - 1, [X | As]); split_string_1([], _N, _L, As) -> {lists:reverse(As), ""}. split_string_2([$^, X | Xs], N, L, As) -> split_string_1(Xs, N - 2, L - 2, [X, $^ | As]); split_string_2([X1, X2, X3 | Xs], N, L, As) when X1 >= $0, X1 =< $7, X2 >= $0, X2 =< $7, X3 >= $0, X3 =< $7 -> split_string_1(Xs, N - 3, L - 3, [X3, X2, X1 | As]); split_string_2([X1, X2 | Xs], N, L, As) when X1 >= $0, X1 =< $7, X2 >= $0, X2 =< $7 -> split_string_1(Xs, N - 2, L - 2, [X2, X1 | As]); split_string_2([X | Xs], N, L, As) -> split_string_1(Xs, N - 1, L - 1, [X | As]). %% Note that there is nothing in `lay_clauses' that actually requires %% that the elements have type `clause'; it just sets up the proper %% context and arranges the elements suitably for clauses. lay_clauses(Cs, Type, Ctxt) -> vertical(seq(Cs, floating(text(";")), Ctxt#ctxt{clause = Type}, fun lay/2)). %% Note that for the clause-making functions, the guard argument %% can be `none', which has different interpretations in different %% contexts. make_fun_clause(P, G, B, Ctxt) -> make_fun_clause(none, P, G, B, Ctxt). make_fun_clause(N, P, G, B, Ctxt) -> D = make_fun_clause_head(N, P, Ctxt), make_case_clause(D, G, B, Ctxt). make_fun_clause_head(N, P, Ctxt) -> D = lay_parentheses(P, Ctxt), if N =:= none -> D; true -> beside(N, D) end. make_rule_clause(N, P, G, B, Ctxt) -> D = make_fun_clause_head(N, P, Ctxt), append_rule_body(B, append_guard(G, D, Ctxt), Ctxt). make_case_clause(P, G, B, Ctxt) -> append_clause_body(B, append_guard(G, P, Ctxt), Ctxt). make_if_clause(_P, G, B, Ctxt) -> %% We ignore the patterns; they should be empty anyway. G1 = if G =:= none -> text("true"); true -> G end, append_clause_body(B, G1, Ctxt). append_clause_body(B, D, Ctxt) -> append_clause_body(B, D, floating(text(" ->")), Ctxt). append_rule_body(B, D, Ctxt) -> append_clause_body(B, D, floating(text(" :-")), Ctxt). append_clause_body(B, D, S, Ctxt) -> sep([beside(D, S), nest(Ctxt#ctxt.break_indent, B)]). append_guard(none, D, _) -> D; append_guard(G, D, Ctxt) -> par([D, follow(text("when"), G, Ctxt#ctxt.sub_indent)], Ctxt#ctxt.break_indent). lay_bit_types([T], Ctxt) -> lay(T, Ctxt); lay_bit_types([T | Ts], Ctxt) -> beside(lay(T, Ctxt), beside(floating(text("-")), lay_bit_types(Ts, Ctxt))). lay_error_info({L, M, T}=T0, Ctxt) when is_integer(L), is_atom(M) -> case catch M:format_error(T) of S when is_list(S) -> if L > 0 -> beside(text(io_lib:format("~w: ",[L])), text(S)); true -> text(S) end; _ -> lay_concrete(T0, Ctxt) end; lay_error_info(T, Ctxt) -> lay_concrete(T, Ctxt). lay_concrete(T, Ctxt) -> lay(erl_syntax:abstract(T), Ctxt). seq([H | T], Separator, Ctxt, Fun) -> case T of [] -> [Fun(H, Ctxt)]; _ -> [maybe_append(Separator, Fun(H, Ctxt)) | seq(T, Separator, Ctxt, Fun)] end; seq([], _, _, _) -> [empty()]. maybe_append(none, D) -> D; maybe_append(Suffix, D) -> beside(D, Suffix). vertical([D]) -> D; vertical([D | Ds]) -> above(D, vertical(Ds)); vertical([]) -> []. vertical_sep(_Sep, [D]) -> D; vertical_sep(Sep, [D | Ds]) -> above(above(D, Sep), vertical_sep(Sep, Ds)); vertical_sep(_Sep, []) -> []. spaces(N) when N > 0 -> [$\040 | spaces(N - 1)]; spaces(_) -> []. tidy_float([$., C | Cs]) -> [$., C | tidy_float_1(Cs)]; % preserve first decimal digit tidy_float([$e | _] = Cs) -> tidy_float_2(Cs); tidy_float([C | Cs]) -> [C | tidy_float(Cs)]; tidy_float([]) -> []. tidy_float_1([$0, $0, $0 | Cs]) -> tidy_float_2(Cs); % cut mantissa at three consecutive zeros. tidy_float_1([$e | _] = Cs) -> tidy_float_2(Cs); tidy_float_1([C | Cs]) -> [C | tidy_float_1(Cs)]; tidy_float_1([]) -> []. tidy_float_2([$e, $+, $0]) -> []; tidy_float_2([$e, $+, $0 | Cs]) -> tidy_float_2([$e, $+ | Cs]); tidy_float_2([$e, $+ | _] = Cs) -> Cs; tidy_float_2([$e, $-, $0]) -> []; tidy_float_2([$e, $-, $0 | Cs]) -> tidy_float_2([$e, $- | Cs]); tidy_float_2([$e, $- | _] = Cs) -> Cs; tidy_float_2([$e | Cs]) -> tidy_float_2([$e, $+ | Cs]); tidy_float_2([_C | Cs]) -> tidy_float_2(Cs); tidy_float_2([]) -> []. %% =====================================================================