%% ===================================================================== %% Licensed under the Apache License, Version 2.0 (the "License"); you may %% not use this file except in compliance with the License. You may obtain %% a copy of the License at %% %% Unless required by applicable law or agreed to in writing, software %% distributed under the License is distributed on an "AS IS" BASIS, %% WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. %% See the License for the specific language governing permissions and %% limitations under the License. %% %% Alternatively, you may use this file under the terms of the GNU Lesser %% General Public License (the "LGPL") as published by the Free Software %% Foundation; either version 2.1, or (at your option) any later version. %% If you wish to allow use of your version of this file only under the %% terms of the LGPL, you should delete the provisions above and replace %% them with the notice and other provisions required by the LGPL; see %% . If you do not delete the provisions %% above, a recipient may use your version of this file under the terms of %% either the Apache License or the LGPL. %% %% @copyright 2001-2006 Richard Carlsson %% @author Richard Carlsson %% @end %% ===================================================================== %% @doc `epp_dodger' - bypasses the Erlang preprocessor. %% %%

This module tokenises and parses most Erlang source code without %% expanding preprocessor directives and macro applications, as long as %% these are syntactically "well-behaved". Because the normal parse %% trees of the `erl_parse' module cannot represent these things %% (normally, they are expanded by the Erlang preprocessor {@link %% //stdlib/epp} before the parser sees them), an extended syntax tree %% is created, using the {@link erl_syntax} module.

%% NOTES: %% %% * It's OK if the result does not parse - then at least nothing %% strange happens, and the user can resort to full preprocessing. %% However, we must avoid generating a token stream that is accepted by %% the parser, but has a different meaning than the intended. A typical %% example is when someone uses token-level string concatenation with %% macros, as in `"foo" ?bar' (where `?bar' expands to a string). If we %% replace the tokens `? bar' with `( ... )', to preserve precedence, %% the result will be parsed as an application `"foo" ( ... )' and cause %% trouble later on. We must detect such cases and report an error. %% %% * It is pointless to add a mechanism for tracking which macros are %% known to take arguments, and which are known to take no arguments, %% since a lot of the time we will not have seen the macro definition %% anyway (it's usually in a header file). Hence, we try to use %% heuristics instead. In most cases, the token sequence `? foo (' %% indicates that it is a call of a macro that is supposed to take %% arguments, but e.g., in the context `: ? foo (', the argument list %% typically belongs to a remote function call, as in `m:?f(...)' and %% should be parsed as `m:(?f)(...)' unless it is actually a try-clause %% pattern such as `throw:?f(...) ->'. %% %% * We do our best to make macros without arguments pass the parsing %% stage transparently. Atoms are accepted in most contexts, but %% variables are not, so we use only atoms to encode these macros. %% Sadly, the parsing sometimes discards even the line number info from %% atom tokens, so we can only use the actual characters for this. %% %% * We recognize `?m(...' at the start of a form and prevent this from %% being interpreted as a macro with arguments, since it is probably a %% function definition. Likewise with attributes `-?m(...'. -module(epp_dodger). -export([parse_file/1, quick_parse_file/1, parse_file/2, quick_parse_file/2, parse/1, quick_parse/1, parse/2, quick_parse/2, parse/3, quick_parse/3, parse_form/2, parse_form/3, quick_parse_form/2, quick_parse_form/3, format_error/1, tokens_to_string/1]). %% The following should be: 1) pseudo-uniquely identifiable, and 2) %% cause nice looking error messages when the parser has to give up. -define(macro_call, '? ('). -define(atom_prefix, "? "). -define(var_prefix, "?,"). -define(pp_form, '?preprocessor declaration?'). %% @type errorinfo() = {ErrorLine::integer(), %% Module::atom(), %% Descriptor::term()}. %% %% This is a so-called Erlang I/O ErrorInfo structure; see the {@link %% //stdlib/io} module for details. -type errorinfo() :: {integer(), atom(), term()}. -type option() :: atom() | {atom(), term()}. %% ===================================================================== %% @spec parse_file(File) -> {ok, Forms} | {error, errorinfo()} %% File = file:filename() %% Forms = [erl_syntax:syntaxTree()] %% %% @equiv parse_file(File, []) -spec parse_file(file:filename()) -> {'ok', erl_syntax:forms()} | {'error', errorinfo()}. parse_file(File) -> parse_file(File, []). %% @spec parse_file(File, Options) -> {ok, Forms} | {error, errorinfo()} %% File = file:filename() %% Options = [term()] %% Forms = [erl_syntax:syntaxTree()] %% %% @doc Reads and parses a file. If successful, `{ok, Forms}' %% is returned, where `Forms' is a list of abstract syntax %% trees representing the "program forms" of the file (cf. %% `erl_syntax:is_form/1'). Otherwise, `{error, errorinfo()}' is %% returned, typically if the file could not be opened. Note that %% parse errors show up as error markers in the returned list of %% forms; they do not cause this function to fail or return %% `{error, errorinfo()}'. %% %% Options: %%
%%
{@type {no_fail, boolean()@}}
%%
If `true', this makes `epp_dodger' replace any program forms %% that could not be parsed with nodes of type `text' (see {@link %% erl_syntax:text/1}), representing the raw token sequence of the %% form, instead of reporting a parse error. The default value is %% `false'.
%%
{@type {clever, boolean()@}}
%%
If set to `true', this makes `epp_dodger' try to repair the %% source code as it seems fit, in certain cases where parsing would %% otherwise fail. Currently, it inserts `++'-operators between string %% literals and macros where it looks like concatenation was intended. %% The default value is `false'.
%%
%% %% @see parse/2 %% @see quick_parse_file/1 %% @see erl_syntax:is_form/1 -spec parse_file(file:filename(), [option()]) -> {'ok', erl_syntax:forms()} | {'error', errorinfo()}. parse_file(File, Options) -> parse_file(File, fun parse/3, Options). %% @spec quick_parse_file(File) -> {ok, Forms} | {error, errorinfo()} %% File = file:filename() %% Forms = [erl_syntax:syntaxTree()] %% %% @equiv quick_parse_file(File, []) -spec quick_parse_file(file:filename()) -> {'ok', erl_syntax:forms()} | {'error', errorinfo()}. quick_parse_file(File) -> quick_parse_file(File, []). %% @spec quick_parse_file(File, Options) -> %% {ok, Forms} | {error, errorinfo()} %% File = file:filename() %% Options = [term()] %% Forms = [erl_syntax:syntaxTree()] %% %% @doc Similar to {@link parse_file/2}, but does a more quick-and-dirty %% processing of the code. Macro definitions and other preprocessor %% directives are discarded, and all macro calls are replaced with %% atoms. This is useful when only the main structure of the code is of %% interest, and not the details. Furthermore, the quick-parse method %% can usually handle more strange cases than the normal, more exact %% parsing. %% %% Options: see {@link parse_file/2}. Note however that for %% `quick_parse_file/2', the option `no_fail' is `true' by default. %% %% @see quick_parse/2 %% @see parse_file/2 -spec quick_parse_file(file:filename(), [option()]) -> {'ok', erl_syntax:forms()} | {'error', errorinfo()}. quick_parse_file(File, Options) -> parse_file(File, fun quick_parse/3, Options ++ [no_fail]). parse_file(File, Parser, Options) -> case do_parse_file(utf8, File, Parser, Options) of {ok, Forms}=Ret -> case find_invalid_unicode(Forms) of none -> Ret; invalid_unicode -> case epp:read_encoding(File) of utf8 -> Ret; _ -> do_parse_file(latin1, File, Parser, Options) end end; Else -> Else end. do_parse_file(DefEncoding, File, Parser, Options) -> case file:open(File, [read]) of {ok, Dev} -> _ = epp:set_encoding(Dev, DefEncoding), try Parser(Dev, 1, Options) after ok = file:close(Dev) end; {error, Error} -> {error, {0, file, Error}} % defer to file:format_error/1 end. find_invalid_unicode([H|T]) -> case H of {error, {_Line, file_io_server, invalid_unicode}} -> invalid_unicode; _Other -> find_invalid_unicode(T) end; find_invalid_unicode([]) -> none. %% ===================================================================== %% @spec parse(IODevice) -> {ok, Forms} | {error, errorinfo()} %% @equiv parse(IODevice, 1) -spec parse(file:io_device()) -> {'ok', erl_syntax:forms()}. parse(Dev) -> parse(Dev, 1). %% @spec parse(IODevice, StartLine) -> {ok, Forms} | {error, errorinfo()} %% IODevice = pid() %% StartLine = integer() %% Forms = [erl_syntax:syntaxTree()] %% %% @equiv parse(IODevice, StartLine, []) %% @see parse/1 -spec parse(file:io_device(), integer()) -> {'ok', erl_syntax:forms()}. parse(Dev, L) -> parse(Dev, L, []). %% @spec parse(IODevice, StartLine, Options) -> %% {ok, Forms} | {error, errorinfo()} %% IODevice = pid() %% StartLine = integer() %% Options = [term()] %% Forms = [erl_syntax:syntaxTree()] %% %% @doc Reads and parses program text from an I/O stream. Characters are %% read from `IODevice' until end-of-file; apart from this, the %% behaviour is the same as for {@link parse_file/2}. `StartLine' is the %% initial line number, which should be a positive integer. %% %% @see parse/2 %% @see parse_file/2 %% @see parse_form/2 %% @see quick_parse/3 -spec parse(file:io_device(), integer(), [option()]) -> {'ok', erl_syntax:forms()}. parse(Dev, L0, Options) -> parse(Dev, L0, fun parse_form/3, Options). %% @spec quick_parse(IODevice) -> {ok, Forms} | {error, errorinfo()} %% @equiv quick_parse(IODevice, 1) -spec quick_parse(file:io_device()) -> {'ok', erl_syntax:forms()}. quick_parse(Dev) -> quick_parse(Dev, 1). %% @spec quick_parse(IODevice, StartLine) -> %% {ok, Forms} | {error, errorinfo()} %% IODevice = pid() %% StartLine = integer() %% Forms = [erl_syntax:syntaxTree()] %% %% @equiv quick_parse(IODevice, StartLine, []) %% @see quick_parse/1 -spec quick_parse(file:io_device(), integer()) -> {'ok', erl_syntax:forms()}. quick_parse(Dev, L) -> quick_parse(Dev, L, []). %% @spec (IODevice, StartLine, Options) -> %% {ok, Forms} | {error, errorinfo()} %% IODevice = pid() %% StartLine = integer() %% Options = [term()] %% Forms = [erl_syntax:syntaxTree()] %% %% @doc Similar to {@link parse/3}, but does a more quick-and-dirty %% processing of the code. See {@link quick_parse_file/2} for details. %% %% @see quick_parse/2 %% @see quick_parse_file/2 %% @see quick_parse_form/2 %% @see parse/3 -spec quick_parse(file:io_device(), integer(), [option()]) -> {'ok', erl_syntax:forms()}. quick_parse(Dev, L0, Options) -> parse(Dev, L0, fun quick_parse_form/3, Options). parse(Dev, L0, Parser, Options) -> parse(Dev, L0, [], Parser, Options). parse(Dev, L0, Fs, Parser, Options) -> case Parser(Dev, L0, Options) of {ok, none, L1} -> parse(Dev, L1, Fs, Parser, Options); {ok, F, L1} -> parse(Dev, L1, [F | Fs], Parser, Options); {error, IoErr, L1} -> parse(Dev, L1, [{error, IoErr} | Fs], Parser, Options); {eof, _L1} -> {ok, lists:reverse(Fs)} end. %% ===================================================================== %% @spec parse_form(IODevice, StartLine) -> {ok, Form, LineNo} %% | {eof, LineNo} %% | {error, errorinfo(), LineNo} %% IODevice = pid() %% StartLine = integer() %% Form = erl_syntax:syntaxTree() %% LineNo = integer() %% %% @equiv parse_form(IODevice, StartLine, []) %% %% @see quick_parse_form/2 -spec parse_form(file:io_device(), integer()) -> {'ok', erl_syntax:forms(), integer()} | {'eof', integer()} | {'error', errorinfo(), integer()}. parse_form(Dev, L0) -> parse_form(Dev, L0, []). %% @spec parse_form(IODevice, StartLine, Options) -> %% {ok, Form, LineNo} %% | {eof, LineNo} %% | {error, errorinfo(), LineNo} %% %% IODevice = pid() %% StartLine = integer() %% Options = [term()] %% Form = erl_syntax:syntaxTree() %% LineNo = integer() %% %% @doc Reads and parses a single program form from an I/O stream. %% Characters are read from `IODevice' until an end-of-form %% marker is found (a period character followed by whitespace), or until %% end-of-file; apart from this, the behaviour is similar to that of %% `parse/3', except that the return values also contain the %% final line number given that `StartLine' is the initial %% line number, and that `{eof, LineNo}' may be returned. %% %% @see parse/3 %% @see parse_form/2 %% @see quick_parse_form/3 -spec parse_form(file:io_device(), integer(), [option()]) -> {'ok', erl_syntax:forms(), integer()} | {'eof', integer()} | {'error', errorinfo(), integer()}. parse_form(Dev, L0, Options) -> parse_form(Dev, L0, fun normal_parser/2, Options). %% @spec quick_parse_form(IODevice, StartLine) -> %% {ok, Form, LineNo} %% | {eof, LineNo} %% | {error, errorinfo(), LineNo} %% IODevice = pid() %% StartLine = integer() %% Form = erl_syntax:syntaxTree() | none %% LineNo = integer() %% %% @equiv quick_parse_form(IODevice, StartLine, []) %% %% @see parse_form/2 -spec quick_parse_form(file:io_device(), integer()) -> {'ok', erl_syntax:forms(), integer()} | {'eof', integer()} | {'error', errorinfo(), integer()}. quick_parse_form(Dev, L0) -> quick_parse_form(Dev, L0, []). %% @spec quick_parse_form(IODevice, StartLine, Options) -> %% {ok, Form, LineNo} %% | {eof, LineNo} %% | {error, errorinfo(), LineNo} %% %% IODevice = pid() %% StartLine = integer() %% Options = [term()] %% Form = erl_syntax:syntaxTree() %% LineNo = integer() %% %% @doc Similar to {@link parse_form/3}, but does a more quick-and-dirty %% processing of the code. See {@link quick_parse_file/2} for details. %% %% @see parse/3 %% @see quick_parse_form/2 %% @see parse_form/3 -spec quick_parse_form(file:io_device(), integer(), [option()]) -> {'ok', erl_syntax:forms(), integer()} | {'eof', integer()} | {'error', errorinfo(), integer()}. quick_parse_form(Dev, L0, Options) -> parse_form(Dev, L0, fun quick_parser/2, Options). -record(opt, {clever = false :: boolean()}). parse_form(Dev, L0, Parser, Options) -> NoFail = proplists:get_bool(no_fail, Options), Opt = #opt{clever = proplists:get_bool(clever, Options)}, case io:scan_erl_form(Dev, "", L0) of {ok, Ts, L1} -> case catch {ok, Parser(Ts, Opt)} of {'EXIT', Term} -> {error, io_error(L1, {unknown, Term}), L1}; {error, Term} -> IoErr = io_error(L1, Term), {error, IoErr, L1}; {parse_error, _IoErr} when NoFail -> {ok, erl_syntax:set_pos( erl_syntax:text(tokens_to_string(Ts)), start_pos(Ts, L1)), L1}; {parse_error, IoErr} -> {error, IoErr, L1}; {ok, F} -> {ok, F, L1} end; {error, _IoErr, _L1} = Err -> Err; {error, _Reason} -> {eof, L0}; % This is probably encoding problem {eof, _L1} = Eof -> Eof end. io_error(L, Desc) -> {L, ?MODULE, Desc}. start_pos([T | _Ts], _L) -> erl_anno:line(element(2, T)); start_pos([], L) -> L. %% Exception-throwing wrapper for the standard Erlang parser stage parse_tokens(Ts) -> parse_tokens(Ts, fun fix_form/1). parse_tokens(Ts, Fix) -> case erl_parse:parse_form(Ts) of {ok, Form} -> Form; {error, IoErr} -> case Fix(Ts) of {form, Form} -> Form; {retry, Ts1, Fix1} -> parse_tokens(Ts1, Fix1); error -> throw({parse_error, IoErr}) end end. %% --------------------------------------------------------------------- %% Quick scanning/parsing - deletes macro definitions and other %% preprocessor directives, and replaces all macro calls with atoms. quick_parser(Ts, _Opt) -> filter_form(parse_tokens(quickscan_form(Ts))). quickscan_form([{'-', _L}, {atom, La, define} | _Ts]) -> kill_form(La); quickscan_form([{'-', _L}, {atom, La, undef} | _Ts]) -> kill_form(La); quickscan_form([{'-', _L}, {atom, La, include} | _Ts]) -> kill_form(La); quickscan_form([{'-', _L}, {atom, La, include_lib} | _Ts]) -> kill_form(La); quickscan_form([{'-', _L}, {atom, La, ifdef} | _Ts]) -> kill_form(La); quickscan_form([{'-', _L}, {atom, La, ifndef} | _Ts]) -> kill_form(La); quickscan_form([{'-', _L}, {atom, La, else} | _Ts]) -> kill_form(La); quickscan_form([{'-', _L}, {atom, La, endif} | _Ts]) -> kill_form(La); quickscan_form([{'-', L}, {'?', _}, {Type, _, _}=N | [{'(', _} | _]=Ts]) when Type =:= atom; Type =:= var -> %% minus, macro and open parenthesis at start of form - assume that %% the macro takes no arguments; e.g. `-?foo(...).' quickscan_macros_1(N, Ts, [{'-', L}]); quickscan_form([{'?', _L}, {Type, _, _}=N | [{'(', _} | _]=Ts]) when Type =:= atom; Type =:= var -> %% macro and open parenthesis at start of form - assume that the %% macro takes no arguments (see scan_macros for details) quickscan_macros_1(N, Ts, []); quickscan_form(Ts) -> quickscan_macros(Ts). kill_form(L) -> [{atom, L, ?pp_form}, {'(', L}, {')', L}, {'->', L}, {atom, L, kill}, {dot, L}]. quickscan_macros(Ts) -> quickscan_macros(Ts, []). quickscan_macros([{'?',_}, {Type, _, A} | Ts], [{string, L, S} | As]) when Type =:= atom; Type =:= var -> %% macro after a string literal: change to a single string {_, Ts1} = skip_macro_args(Ts), S1 = S ++ quick_macro_string(A), quickscan_macros(Ts1, [{string, L, S1} | As]); quickscan_macros([{'?',_}, {Type, _, _}=N | [{'(',_}|_]=Ts], [{':',_}|_]=As) when Type =:= atom; Type =:= var -> %% macro and open parenthesis after colon - check the token %% following the arguments (see scan_macros for details) Ts1 = case skip_macro_args(Ts) of {_, [{'->',_} | _] = Ts2} -> Ts2; {_, [{'when',_} | _] = Ts2} -> Ts2; _ -> Ts %% assume macro without arguments end, quickscan_macros_1(N, Ts1, As); quickscan_macros([{'?',_}, {Type, _, _}=N | Ts], As) when Type =:= atom; Type =:= var -> %% macro with or without arguments {_, Ts1} = skip_macro_args(Ts), quickscan_macros_1(N, Ts1, As); quickscan_macros([T | Ts], As) -> quickscan_macros(Ts, [T | As]); quickscan_macros([], As) -> lists:reverse(As). %% (after a macro has been found and the arglist skipped, if any) quickscan_macros_1({_Type, _, A}, [{string, L, S} | Ts], As) -> %% string literal following macro: change to single string S1 = quick_macro_string(A) ++ S, quickscan_macros(Ts, [{string, L, S1} | As]); quickscan_macros_1({_Type, L, A}, Ts, As) -> %% normal case - just replace the macro with an atom quickscan_macros(Ts, [{atom, L, quick_macro_atom(A)} | As]). quick_macro_atom(A) -> list_to_atom("?" ++ atom_to_list(A)). quick_macro_string(A) -> "(?" ++ atom_to_list(A) ++ ")". %% Skipping to the end of a macro call, tracking open/close constructs. %% @spec (Tokens) -> {Skipped, Rest} skip_macro_args([{'(',_}=T | Ts]) -> skip_macro_args(Ts, [')'], [T]); skip_macro_args(Ts) -> {[], Ts}. skip_macro_args([{'(',_}=T | Ts], Es, As) -> skip_macro_args(Ts, [')' | Es], [T | As]); skip_macro_args([{'{',_}=T | Ts], Es, As) -> skip_macro_args(Ts, ['}' | Es], [T | As]); skip_macro_args([{'[',_}=T | Ts], Es, As) -> skip_macro_args(Ts, [']' | Es], [T | As]); skip_macro_args([{'<<',_}=T | Ts], Es, As) -> skip_macro_args(Ts, ['>>' | Es], [T | As]); skip_macro_args([{'begin',_}=T | Ts], Es, As) -> skip_macro_args(Ts, ['end' | Es], [T | As]); skip_macro_args([{'if',_}=T | Ts], Es, As) -> skip_macro_args(Ts, ['end' | Es], [T | As]); skip_macro_args([{'case',_}=T | Ts], Es, As) -> skip_macro_args(Ts, ['end' | Es], [T | As]); skip_macro_args([{'receive',_}=T | Ts], Es, As) -> skip_macro_args(Ts, ['end' | Es], [T | As]); skip_macro_args([{'try',_}=T | Ts], Es, As) -> skip_macro_args(Ts, ['end' | Es], [T | As]); skip_macro_args([{'cond',_}=T | Ts], Es, As) -> skip_macro_args(Ts, ['end' | Es], [T | As]); skip_macro_args([{E,_}=T | Ts], [E], As) -> %final close {lists:reverse([T | As]), Ts}; skip_macro_args([{E,_}=T | Ts], [E | Es], As) -> %matching close skip_macro_args(Ts, Es, [T | As]); skip_macro_args([T | Ts], Es, As) -> skip_macro_args(Ts, Es, [T | As]); skip_macro_args([], _Es, _As) -> throw({error, macro_args}). filter_form({function, _, ?pp_form, _, [{clause, _, [], [], [{atom, _, kill}]}]}) -> none; filter_form(T) -> T. %% --------------------------------------------------------------------- %% Normal parsing - try to preserve all information normal_parser(Ts, Opt) -> rewrite_form(parse_tokens(scan_form(Ts, Opt))). scan_form([{'-', _L}, {atom, La, define} | Ts], Opt) -> [{atom, La, ?pp_form}, {'(', La}, {')', La}, {'->', La}, {atom, La, define} | scan_macros(Ts, Opt)]; scan_form([{'-', _L}, {atom, La, undef} | Ts], Opt) -> [{atom, La, ?pp_form}, {'(', La}, {')', La}, {'->', La}, {atom, La, undef} | scan_macros(Ts, Opt)]; scan_form([{'-', _L}, {atom, La, include} | Ts], Opt) -> [{atom, La, ?pp_form}, {'(', La}, {')', La}, {'->', La}, {atom, La, include} | scan_macros(Ts, Opt)]; scan_form([{'-', _L}, {atom, La, include_lib} | Ts], Opt) -> [{atom, La, ?pp_form}, {'(', La}, {')', La}, {'->', La}, {atom, La, include_lib} | scan_macros(Ts, Opt)]; scan_form([{'-', _L}, {atom, La, ifdef} | Ts], Opt) -> [{atom, La, ?pp_form}, {'(', La}, {')', La}, {'->', La}, {atom, La, ifdef} | scan_macros(Ts, Opt)]; scan_form([{'-', _L}, {atom, La, ifndef} | Ts], Opt) -> [{atom, La, ?pp_form}, {'(', La}, {')', La}, {'->', La}, {atom, La, ifndef} | scan_macros(Ts, Opt)]; scan_form([{'-', _L}, {atom, La, else} | Ts], Opt) -> [{atom, La, ?pp_form}, {'(', La}, {')', La}, {'->', La}, {atom, La, else} | scan_macros(Ts, Opt)]; scan_form([{'-', _L}, {atom, La, endif} | Ts], Opt) -> [{atom, La, ?pp_form}, {'(', La}, {')', La}, {'->', La}, {atom, La, endif} | scan_macros(Ts, Opt)]; scan_form([{'-', L}, {'?', L1}, {Type, _, _}=N | [{'(', _} | _]=Ts], Opt) when Type =:= atom; Type =:= var -> %% minus, macro and open parenthesis at start of form - assume that %% the macro takes no arguments; e.g. `-?foo(...).' macro(L1, N, Ts, [{'-', L}], Opt); scan_form([{'?', L}, {Type, _, _}=N | [{'(', _} | _]=Ts], Opt) when Type =:= atom; Type =:= var -> %% macro and open parenthesis at start of form - assume that the %% macro takes no arguments; probably a function declaration on the %% form `?m(...) -> ...', which will not parse if it is rewritten as %% `(?m(...)) -> ...', so it must be handled as `(?m)(...) -> ...' macro(L, N, Ts, [], Opt); scan_form(Ts, Opt) -> scan_macros(Ts, Opt). scan_macros(Ts, Opt) -> scan_macros(Ts, [], Opt). scan_macros([{'?', _}=M, {Type, _, _}=N | Ts], [{string, L, _}=S | As], #opt{clever = true}=Opt) when Type =:= atom; Type =:= var -> %% macro after a string literal: be clever and insert ++ scan_macros([M, N | Ts], [{'++', L}, S | As], Opt); scan_macros([{'?', L}, {Type, _, _}=N | [{'(',_}|_]=Ts], [{':',_}|_]=As, Opt) when Type =:= atom; Type =:= var -> %% macro and open parentheses after colon - probably a call %% `m:?F(...)' so the argument list might belong to the call, not %% the macro - but it could also be a try-clause pattern %% `...:?T(...) ->' - we need to check the token following the %% arguments to decide {Args, Rest} = skip_macro_args(Ts), case Rest of [{'->',_} | _] -> macro_call(Args, L, N, Rest, As, Opt); [{'when',_} | _] -> macro_call(Args, L, N, Rest, As, Opt); _ -> macro(L, N, Ts, As, Opt) end; scan_macros([{'?', L}, {Type, _, _}=N | [{'(',_}|_]=Ts], As, Opt) when Type =:= atom; Type =:= var -> %% macro with arguments {Args, Rest} = skip_macro_args(Ts), macro_call(Args, L, N, Rest, As, Opt); scan_macros([{'?', L }, {Type, _, _}=N | Ts], As, Opt) when Type =:= atom; Type =:= var -> %% macro without arguments macro(L, N, Ts, As, Opt); scan_macros([T | Ts], As, Opt) -> scan_macros(Ts, [T | As], Opt); scan_macros([], As, _Opt) -> lists:reverse(As). %% Rewriting to a call which will be recognized by the post-parse pass %% (we insert parentheses to preserve the precedences when parsing). macro(L, {Type, _, A}, Rest, As, Opt) -> scan_macros_1([], Rest, [{atom,L,macro_atom(Type,A)} | As], Opt). macro_call([{'(',_}, {')',_}], L, {_, Ln, _}=N, Rest, As, Opt) -> {Open, Close} = parentheses(As), scan_macros_1([], Rest, lists:reverse(Open ++ [{atom,L,?macro_call}, {'(',L}, N, {')',Ln}] ++ Close, As), Opt); macro_call([{'(',_} | Args], L, {_, Ln, _}=N, Rest, As, Opt) -> {Open, Close} = parentheses(As), %% note that we must scan the argument list; it may not be skipped scan_macros_1(Args ++ Close, Rest, lists:reverse(Open ++ [{atom,L,?macro_call}, {'(',L}, N, {',',Ln}], As), Opt). macro_atom(atom, A) -> list_to_atom(?atom_prefix ++ atom_to_list(A)); macro_atom(var, A) -> list_to_atom(?var_prefix ++ atom_to_list(A)). %% don't insert parentheses after a string token, to avoid turning %% `"string" ?macro' into a "function application" `"string"(...)' %% (see note at top of file) parentheses([{string, _, _} | _]) -> {[], []}; parentheses(_) -> {[{'(',0}], [{')',0}]}. %% (after a macro has been found and the arglist skipped, if any) scan_macros_1(Args, [{string, L, _} | _]=Rest, As, #opt{clever = true}=Opt) -> %% string literal following macro: be clever and insert ++ scan_macros(Args ++ [{'++', L} | Rest], As, Opt); scan_macros_1(Args, Rest, As, Opt) -> %% normal case - continue scanning scan_macros(Args ++ Rest, As, Opt). rewrite_form({function, L, ?pp_form, _, [{clause, _, [], [], [{call, _, A, As}]}]}) -> erl_syntax:set_pos(erl_syntax:attribute(A, rewrite_list(As)), L); rewrite_form({function, L, ?pp_form, _, [{clause, _, [], [], [A]}]}) -> erl_syntax:set_pos(erl_syntax:attribute(A), L); rewrite_form(T) -> rewrite(T). rewrite_list([T | Ts]) -> [rewrite(T) | rewrite_list(Ts)]; rewrite_list([]) -> []. %% Note: as soon as we start using erl_syntax:subtrees/1 and similar %% functions, we cannot assume that we know the exact representation of %% the syntax tree anymore - we must use erl_syntax functions to analyze %% and decompose the data. rewrite(Node) -> case erl_syntax:type(Node) of atom -> case atom_to_list(erl_syntax:atom_value(Node)) of ?atom_prefix ++ As -> A1 = list_to_atom(As), N = erl_syntax:copy_pos(Node, erl_syntax:atom(A1)), erl_syntax:copy_pos(Node, erl_syntax:macro(N)); ?var_prefix ++ As -> A1 = list_to_atom(As), N = erl_syntax:copy_pos(Node, erl_syntax:variable(A1)), erl_syntax:copy_pos(Node, erl_syntax:macro(N)); _ -> Node end; application -> F = erl_syntax:application_operator(Node), case erl_syntax:type(F) of atom -> case erl_syntax:atom_value(F) of ?macro_call -> [A | As] = erl_syntax:application_arguments(Node), M = erl_syntax:macro(A, rewrite_list(As)), erl_syntax:copy_pos(Node, M); _ -> rewrite_1(Node) end; _ -> rewrite_1(Node) end; _ -> rewrite_1(Node) end. rewrite_1(Node) -> case erl_syntax:subtrees(Node) of [] -> Node; Gs -> Node1 = erl_syntax:make_tree(erl_syntax:type(Node), [[rewrite(T) || T <- Ts] || Ts <- Gs]), erl_syntax:copy_pos(Node, Node1) end. %% attempting a rescue operation on a token sequence for a single form %% if it could not be parsed after the normal treatment fix_form([{atom, _, ?pp_form}, {'(', _}, {')', _}, {'->', _}, {atom, _, define}, {'(', _} | _]=Ts) -> case lists:reverse(Ts) of [{dot, _}, {')', _} | _] -> {retry, Ts, fun fix_define/1}; [{dot, L} | Ts1] -> Ts2 = lists:reverse([{dot, L}, {')', L} | Ts1]), {retry, Ts2, fun fix_define/1}; _ -> error end; fix_form(_Ts) -> error. fix_define([{atom, L, ?pp_form}, {'(', _}, {')', _}, {'->', _}, {atom, La, define}, {'(', _}, N, {',', _} | Ts]) -> [{dot, _}, {')', _} | Ts1] = lists:reverse(Ts), S = tokens_to_string(lists:reverse(Ts1)), A = erl_syntax:set_pos(erl_syntax:atom(define), La), Txt = erl_syntax:set_pos(erl_syntax:text(S), La), {form, erl_syntax:set_pos(erl_syntax:attribute(A, [N, Txt]), L)}; fix_define(_Ts) -> error. %% @spec tokens_to_string(Tokens::[term()]) -> string() %% %% @doc Generates a string corresponding to the given token sequence. %% The string can be re-tokenized to yield the same token list again. -spec tokens_to_string([term()]) -> string(). tokens_to_string([{atom,_,A} | Ts]) -> io_lib:write_atom(A) ++ " " ++ tokens_to_string(Ts); tokens_to_string([{string, _, S} | Ts]) -> io_lib:write_string(S) ++ " " ++ tokens_to_string(Ts); tokens_to_string([{char, _, C} | Ts]) -> io_lib:write_char(C) ++ " " ++ tokens_to_string(Ts); tokens_to_string([{float, _, F} | Ts]) -> float_to_list(F) ++ " " ++ tokens_to_string(Ts); tokens_to_string([{integer, _, N} | Ts]) -> integer_to_list(N) ++ " " ++ tokens_to_string(Ts); tokens_to_string([{var, _, A} | Ts]) -> atom_to_list(A) ++ " " ++ tokens_to_string(Ts); tokens_to_string([{dot, _} | Ts]) -> ".\n" ++ tokens_to_string(Ts); tokens_to_string([{A, _} | Ts]) -> atom_to_list(A) ++ " " ++ tokens_to_string(Ts); tokens_to_string([]) -> "". %% @spec format_error(Descriptor::term()) -> string() %% @hidden %% @doc Callback function for formatting error descriptors. Not for %% normal use. -spec format_error(term()) -> string(). format_error(macro_args) -> errormsg("macro call missing end parenthesis"); format_error({unknown, Reason}) -> errormsg(io_lib:format("unknown error: ~P", [Reason, 15])). errormsg(String) -> io_lib:format("~s: ~s", [?MODULE, String]). %% =====================================================================