%% Copyright (c) 2008,2009 Robert Virding. All rights reserved. %% %% Redistribution and use in source and binary forms, with or without %% modification, are permitted provided that the following conditions %% are met: %% %% 1. Redistributions of source code must retain the above copyright %% notice, this list of conditions and the following disclaimer. %% 2. Redistributions in binary form must reproduce the above copyright %% notice, this list of conditions and the following disclaimer in the %% documentation and/or other materials provided with the distribution. %% %% THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS %% "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT %% LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS %% FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE %% COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, %% INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, %% BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; %% LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER %% CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT %% LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN %% ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE %% POSSIBILITY OF SUCH DAMAGE. %%% A Lexical Analyser Generator for Erlang. %%% %%% Most of the algorithms used here are taken pretty much as %%% described in the "Dragon Book" by Aho, Sethi and Ullman. Some %%% completing details were taken from "Compiler Design in C" by %%% Hollub. -module(leex). -export([compile/3,file/1,file/2,format_error/1]). -import(lists, [member/2,reverse/1,sort/1,delete/2, keysort/2,keydelete/3, map/2,foldl/3,foreach/2,flatmap/2]). -import(ordsets, [is_element/2,add_element/2,union/2]). -import(orddict, [store/3]). -include("erl_compile.hrl"). %%-include_lib("stdlib/include/erl_compile.hrl"). -define(LEEXINC, "leexinc.hrl"). % Include file -define(LEEXLIB, parsetools). % Leex is in lib parsetools %%-define(LEEXLIB, leex). % Leex is in lib leex -define(DEFS_HEAD, "Definitions."). -define(RULE_HEAD, "Rules."). -define(CODE_HEAD, "Erlang code."). -record(leex, {xfile=[], % Xrl file efile=[], % Erl file ifile=[], % Include file gfile=[], % Graph file module, % Module name opts=[], % Options encoding=none, % Encoding of Xrl file % posix=false, % POSIX regular expressions errors=[], warnings=[] }). -record(nfa_state, {no,edges=[],accept=noaccept}). -record(dfa_state, {no,nfa=[],trans=[],accept=noaccept}). %%% %%% Exported functions %%% %%% Interface to erl_compile. compile(Input0, Output0, #options{warning = WarnLevel, verbose=Verbose, includes=Includes, specific=Specific}) -> Input = assure_extension(shorten_filename(Input0), ".xrl"), Output = assure_extension(shorten_filename(Output0), ".erl"), Includefile = lists:sublist(Includes, 1), Werror = proplists:get_bool(warnings_as_errors, Specific), Opts = [{scannerfile,Output},{includefile,Includefile},{verbose,Verbose}, {report_errors,true},{report_warnings,WarnLevel > 0}, {warnings_as_errors, Werror}], case file(Input, Opts) of {ok, _} -> ok; error -> error end. %% file(File) -> ok | error. %% file(File, Options) -> ok | error. file(File) -> file(File, []). file(File, Opts0) -> case is_filename(File) of no -> erlang:error(badarg, [File,Opts0]); _ -> ok end, Opts = case options(Opts0) of badarg -> erlang:error(badarg, [File,Opts0]); Options -> Options end, St0 = #leex{}, St1 = filenames(File, Opts, St0), % Get all the filenames St = try {ok,REAs,Actions,Code,St2} = parse_file(St1), {DFA,DF} = make_dfa(REAs, St2), case werror(St2) of false -> St3 = out_file(St2, DFA, DF, Actions, Code), case lists:member(dfa_graph, St3#leex.opts) of true -> out_dfa_graph(St3, DFA, DF); false -> St3 end; true -> St2 end catch #leex{}=St4 -> St4 end, leex_ret(St). format_error({file_error, Reason}) -> io_lib:fwrite("~ts",[file:format_error(Reason)]); format_error(missing_defs) -> "missing Definitions"; format_error(missing_rules) -> "missing Rules"; format_error(missing_code) -> "missing Erlang code"; format_error(empty_rules) -> "no rules"; format_error(bad_rule) -> "bad rule"; format_error({regexp,E})-> Es = case E of {interval_range,_} -> "interval range"; {unterminated,Cs} -> "unterminated " ++ Cs; {illegal_char,Cs} -> "illegal character " ++ Cs; %% {posix_cc,What} -> %% ["illegal POSIX character class ",io_lib:write_string(What)]; {char_class,What} -> ["illegal character class ",io_lib:write_string(What)] end, ["bad regexp `",Es,"'"]; format_error(ignored_characters) -> "ignored characters"; format_error(cannot_parse) -> io_lib:fwrite("cannot parse; probably encoding mismatch", []). %%% %%% Local functions %%% assure_extension(File, Ext) -> lists:concat([strip_extension(File, Ext), Ext]). %% Assumes File is a filename. strip_extension(File, Ext) -> case filename:extension(File) of Ext -> filename:rootname(File); _Other -> File end. options(Options0) when is_list(Options0) -> try Options = flatmap(fun(return) -> short_option(return, true); (report) -> short_option(report, true); ({return,T}) -> short_option(return, T); ({report,T}) -> short_option(report, T); (T) -> [T] end, Options0), options(Options, [scannerfile,includefile,report_errors, report_warnings,warnings_as_errors, return_errors,return_warnings, verbose,dfa_graph], []) catch error: _ -> badarg end; options(Option) -> options([Option]). short_option(return, T) -> [{return_errors,T}, {return_warnings,T}]; short_option(report, T) -> [{report_errors,T}, {report_warnings,T}]. options(Options0, [Key|Keys], L) when is_list(Options0) -> Options = case member(Key, Options0) of true -> [atom_option(Key)|delete(Key, Options0)]; false -> Options0 end, V = case lists:keyfind(Key, 1, Options) of {Key, Filename0} when Key =:= includefile; Key =:= scannerfile -> case is_filename(Filename0) of no -> badarg; Filename -> {ok,[{Key,Filename}]} end; {Key, Bool} = KB when is_boolean(Bool) -> {ok, [KB]}; {Key, _} -> badarg; false -> {ok,[{Key,default_option(Key)}]} end, case V of badarg -> badarg; {ok,KeyValueL} -> NewOptions = keydelete(Key, 1, Options), options(NewOptions, Keys, KeyValueL ++ L) end; options([], [], L) -> foldl(fun({_,false}, A) -> A; ({Tag,true}, A) -> [Tag|A]; (F,A) -> [F|A] end, [], L); options(_Options, _, _L) -> badarg. default_option(dfa_graph) -> false; default_option(includefile) -> []; default_option(report_errors) -> true; default_option(report_warnings) -> true; default_option(warnings_as_errors) -> false; default_option(return_errors) -> false; default_option(return_warnings) -> false; default_option(scannerfile) -> []; default_option(verbose) -> false. atom_option(dfa_graph) -> {dfa_graph,true}; atom_option(report_errors) -> {report_errors,true}; atom_option(report_warnings) -> {report_warnings,true}; atom_option(warnings_as_errors) -> {warnings_as_errors,true}; atom_option(return_errors) -> {return_errors,true}; atom_option(return_warnings) -> {return_warnings,true}; atom_option(verbose) -> {verbose,true}; atom_option(Key) -> Key. is_filename(T) -> try filename:flatten(T) catch error: _ -> no end. shorten_filename(Name0) -> {ok,Cwd} = file:get_cwd(), case string:prefix(Name0, Cwd) of nomatch -> Name0; Rest -> case unicode:characters_to_list(Rest) of "/"++N -> N; N -> N end end. leex_ret(St) -> report_errors(St), report_warnings(St), Es = pack_errors(St#leex.errors), Ws = pack_warnings(St#leex.warnings), Werror = werror(St), if Werror -> do_error_return(St, Es, Ws); Es =:= [] -> case member(return_warnings, St#leex.opts) of true -> {ok, St#leex.efile, Ws}; false -> {ok, St#leex.efile} end; true -> do_error_return(St, Es, Ws) end. do_error_return(St, Es, Ws) -> case member(return_errors, St#leex.opts) of true -> {error, Es, Ws}; false -> error end. werror(St) -> St#leex.warnings =/= [] andalso member(warnings_as_errors, St#leex.opts). pack_errors([{File,_} | _] = Es) -> [{File, flatmap(fun({_,E}) -> [E] end, sort(Es))}]; pack_errors([]) -> []. pack_warnings([{File,_} | _] = Ws) -> [{File, flatmap(fun({_,W}) -> [W] end, sort(Ws))}]; pack_warnings([]) -> []. report_errors(St) -> when_opt(fun () -> foreach(fun({File,{none,Mod,E}}) -> io:fwrite("~ts: ~ts\n", [File,Mod:format_error(E)]); ({File,{Line,Mod,E}}) -> io:fwrite("~ts:~w: ~ts\n", [File,Line,Mod:format_error(E)]) end, sort(St#leex.errors)) end, report_errors, St#leex.opts). report_warnings(St) -> Werror = member(warnings_as_errors, St#leex.opts), Prefix = case Werror of true -> ""; false -> "Warning: " end, ReportWerror = Werror andalso member(report_errors, St#leex.opts), ShouldReport = member(report_warnings, St#leex.opts) orelse ReportWerror, when_bool(fun () -> foreach(fun({File,{none,Mod,W}}) -> io:fwrite("~ts: ~s~ts\n", [File,Prefix, Mod:format_error(W)]); ({File,{Line,Mod,W}}) -> io:fwrite("~ts:~w: ~s~ts\n", [File,Line,Prefix, Mod:format_error(W)]) end, sort(St#leex.warnings)) end, ShouldReport). -spec add_error(_, #leex{}) -> no_return(). add_error(E, St) -> add_error(St#leex.xfile, E, St). add_error(File, Error, St) -> throw(St#leex{errors = [{File,Error}|St#leex.errors]}). add_warning(Line, W, St) -> St#leex{warnings = [{St#leex.xfile,{Line,leex,W}}|St#leex.warnings]}. %% filenames(File, Options, State) -> State. %% The default output dir is the current directory unless an %% explicit one has been given in the options. filenames(File, Opts, St0) -> Dir = filename:dirname(File), Base = filename:basename(File, ".xrl"), Xfile = filename:join(Dir, Base ++ ".xrl"), Efile = Base ++ ".erl", Gfile = Base ++ ".dot", Module = list_to_atom(Base), St1 = St0#leex{xfile=Xfile, opts=Opts, module=Module}, {includefile,Ifile0} = lists:keyfind(includefile, 1, Opts), Ifile = inc_file_name(Ifile0), %% Test for explicit scanner file. {scannerfile,Ofile} = lists:keyfind(scannerfile, 1, Opts), if Ofile =:= [] -> St1#leex{efile=filename:join(Dir, Efile), ifile=Ifile, gfile=filename:join(Dir, Gfile)}; true -> D = filename:dirname(Ofile), St1#leex{efile=Ofile, ifile=Ifile, gfile=filename:join(D, Gfile)} end. when_opt(Do, Opt, Opts) -> case member(Opt, Opts) of true -> Do(); false -> ok end. when_bool(Do, Bool) -> case Bool of true -> Do(); false -> ok end. verbose_print(St, Format, Args) -> when_opt(fun () -> io:fwrite(Format, Args) end, verbose, St#leex.opts). %% parse_file(State) -> {ok,[REA],[Action],Code,NewState} | throw(NewState) %% when %% REA = {RegExp,ActionNo}; %% Action = {ActionNo,ActionString}; %% Code = {StartLine, StartPos, NumOfLines}. Where the Erlang code is. %% %% Read and parse the file Xfile. %% After each section of the file has been parsed we directly call the %% next section. This is done when we detect a line we don't recognise %% in the current section. The file format is very simple and Erlang %% token based, we allow empty lines and Erlang style comments. parse_file(St0) -> case file:open(St0#leex.xfile, [read]) of {ok,Xfile} -> St1 = St0#leex{encoding = epp:set_encoding(Xfile)}, try verbose_print(St1, "Parsing file ~ts, ", [St1#leex.xfile]), %% We KNOW that errors throw so we can ignore them here. {ok,Line1,St2} = parse_head(Xfile, St1), {ok,Line2,Macs,St3} = parse_defs(Xfile, Line1, St2), {ok,Line3,REAs,Actions,St4} = parse_rules(Xfile, Line2, Macs, St3), {ok,Code,St5} = parse_code(Xfile, Line3, St4), verbose_print(St5, "contained ~w rules.~n", [length(REAs)]), {ok,REAs,Actions,Code,St5} after ok = file:close(Xfile) end; {error,Error} -> add_error({none,leex,{file_error,Error}}, St0) end. %% parse_head(File, State) -> {ok,NextLine,State}. %% Parse the head of the file. Skip all comments and blank lines. parse_head(Ifile, St) -> {ok,nextline(Ifile, 0, St),St}. %% parse_defs(File, Line, State) -> {ok,NextLine,Macros,State}. %% Parse the macro definition section of a file. This must exist. %% The section is ended by a non-blank line which is not a macro def. parse_defs(Ifile, {ok,?DEFS_HEAD ++ Rest,L}, St) -> St1 = warn_ignored_chars(L, Rest, St), parse_defs(Ifile, nextline(Ifile, L, St), [], St1); parse_defs(_, {ok,_,L}, St) -> add_error({L,leex,missing_defs}, St); parse_defs(_, {eof,L}, St) -> add_error({L,leex,missing_defs}, St). parse_defs(Ifile, {ok,Chars,L}=Line, Ms, St) -> %% This little beauty matches out a macro definition, RE's are so clear. MS = "^[ \t]*([A-Z_][A-Za-z0-9_]*)[ \t]*=[ \t]*([^ \t\r\n]*)[ \t\r\n]*\$", case re:run(Chars, MS, [{capture,all_but_first,list},unicode]) of {match,[Name,Def]} -> %%io:fwrite("~p = ~p\n", [Name,Def]), parse_defs(Ifile, nextline(Ifile, L, St), [{Name,Def}|Ms], St); _ -> {ok,Line,Ms,St} % Anything else end; parse_defs(_, Line, Ms, St) -> {ok,Line,Ms,St}. %% parse_rules(File, Line, Macros, State) -> {ok,NextLine,REAs,Actions,State}. %% Parse the RE rules section of the file. This must exist. parse_rules(Ifile, {ok,?RULE_HEAD ++ Rest,L}, Ms, St) -> St1 = warn_ignored_chars(L, Rest, St), parse_rules(Ifile, nextline(Ifile, L, St), Ms, [], [], 0, St1); parse_rules(_, {ok,_,L}, _, St) -> add_error({L,leex,missing_rules}, St); parse_rules(_, {eof,L}, _, St) -> add_error({L,leex,missing_rules}, St). %% parse_rules(File, Result, Macros, RegExpActions, Actions, Acount, State) -> %% {ok,NextCLine,RegExpActions,Actions,NewState} | throw(NewState) parse_rules(Ifile, NextLine, Ms, REAs, As, N, St) -> case NextLine of {ok,?CODE_HEAD ++ _Rest,_} -> parse_rules_end(Ifile, NextLine, REAs, As, St); {ok,Chars,L0} -> %%io:fwrite("~w: ~p~n", [L0,Chars]), case collect_rule(Ifile, Chars, L0) of {ok,Re,Atoks,L1} -> {ok,REA,A,St1} = parse_rule(Re, L0, Atoks, Ms, N, St), parse_rules(Ifile, nextline(Ifile, L1, St), Ms, [REA|REAs], [A|As], N+1, St1); {error,E} -> add_error(E, St) end; {eof,_} -> parse_rules_end(Ifile, NextLine, REAs, As, St) end. parse_rules_end(_, {ok,_,L}, [], [], St) -> add_error({L,leex,empty_rules}, St); parse_rules_end(_, {eof,L}, [], [], St) -> add_error({L,leex,empty_rules}, St); parse_rules_end(_, NextLine, REAs, As, St) -> %% Must be *VERY* careful to put rules in correct order! {ok,NextLine,reverse(REAs),reverse(As),St}. %% collect_rule(File, Line, Lineno) -> %% {ok,RegExp,ActionTokens,NewLineno} | {error,E}. %% Collect a complete rule by reading lines until the the regexp and %% action has been read. Keep track of line number. collect_rule(Ifile, Chars, L0) -> {RegExp,Rest} = string:take(Chars, " \t\r\n", true), case collect_action(Ifile, Rest, L0, []) of {ok,[{':',_}|Toks],L1} -> {ok,RegExp,Toks,L1}; {ok,_,_} -> {error,{L0,leex,bad_rule}}; {eof,L1} -> {error,{L1,leex,bad_rule}}; {error,E,_} -> {error,E} end. collect_action(_Ifile, {error, _}, L, _Cont0) -> {error, {L, leex, cannot_parse}, ignored_end_line}; collect_action(Ifile, Chars, L0, Cont0) -> case erl_scan:tokens(Cont0, Chars, L0) of {done,{ok,Toks,_},_} -> {ok,Toks,L0}; {done,{eof,_},_} -> {eof,L0}; {done,{error,E,_},_} -> {error,E,L0}; {more,Cont1} -> collect_action(Ifile, io:get_line(Ifile, leex), L0+1, Cont1) end. %% parse_rule(RegExpString, RegExpLine, ActionTokens, Macros, Counter, State) -> %% {ok,{RE,Action},ActionData,State}. %% Parse one regexp after performing macro substition. parse_rule(S, Line, [{dot,_}], Ms, N, St) -> case parse_rule_regexp(S, Ms, St) of {ok,R} -> {ok,{R,N},{N,empty_action},St}; {error,E} -> add_error({Line,leex,E}, St) end; parse_rule(S, Line, Atoks, Ms, N, St) -> case parse_rule_regexp(S, Ms, St) of {ok,R} -> %%io:fwrite("RE = ~p~n", [R]), %% Check for token variables. TokenChars = var_used('TokenChars', Atoks), TokenLen = var_used('TokenLen', Atoks), TokenLine = var_used('TokenLine', Atoks), {ok,{R,N},{N,Atoks,TokenChars,TokenLen,TokenLine},St}; {error,E} -> add_error({Line,leex,E}, St) end. var_used(Name, Toks) -> case lists:keyfind(Name, 3, Toks) of {var,_,Name} -> true; %It's the var we want _ -> false end. %% parse_rule_regexp(RegExpString, Macros, State) -> %% {ok,RegExp} | {error,Error}. %% Substitute in macros and parse RegExpString. Cannot use re:replace %% here as it uses info in replace string (&). parse_rule_regexp(RE0, [{M,Exp}|Ms], St) -> Split= re:split(RE0, "\\{" ++ M ++ "\\}", [{return,list},unicode]), RE1 = lists:append(lists:join(Exp, Split)), parse_rule_regexp(RE1, Ms, St); parse_rule_regexp(RE, [], St) -> %%io:fwrite("RE = ~p~n", [RE]), case re_parse(RE, St) of {ok,R} -> {ok,R}; {error,E} -> {error,{regexp,E}} end. %% parse_code(File, Line, State) -> {ok,Code,NewState}. %% Finds the line and the position where the code section of the file %% begins. This must exist. parse_code(Ifile, {ok,?CODE_HEAD ++ Rest,CodeL}, St) -> St1 = warn_ignored_chars(CodeL, Rest, St), {ok, CodePos} = file:position(Ifile, cur), %% Just count the lines; copy the code from file to file later. EndCodeLine = count_lines(Ifile, CodeL, St), NCodeLines = EndCodeLine - CodeL, {ok,{CodeL,CodePos,NCodeLines},St1}; parse_code(_, {ok,_,L}, St) -> add_error({L,leex,missing_code}, St); parse_code(_, {eof,L}, St) -> add_error({L,leex,missing_code}, St). count_lines(File, N, St) -> case io:get_line(File, leex) of eof -> N; {error, _} -> add_error({N+1, leex, cannot_parse}, St); _Line -> count_lines(File, N+1, St) end. %% nextline(InputFile, PrevLineNo, State) -> {ok,Chars,LineNo} | {eof,LineNo}. %% Get the next line skipping comment lines and blank lines. nextline(Ifile, L, St) -> case io:get_line(Ifile, leex) of eof -> {eof,L}; {error, _} -> add_error({L+1, leex, cannot_parse}, St); Chars -> case string:take(Chars, " \t\n") of {_, [$%|_Rest]} -> nextline(Ifile, L+1, St); {_, []} -> nextline(Ifile, L+1, St); _Other -> {ok,Chars,L+1} end end. warn_ignored_chars(Line, S, St) -> case non_white(S) of [] -> St; _ -> add_warning(Line, ignored_characters, St) end. non_white(S) -> [C || C <- S, C > $\s, C < $\200 orelse C > $\240]. %% This is the regular expression grammar used. It is equivalent to the %% one used in AWK, except that we allow ^ $ to be used anywhere and fail %% in the matching. %% %% reg -> alt : '$1'. %% alt -> seq "|" seq ... : {alt,['$1','$2'...]}. %% seq -> repeat repeat ... : {seq,['$1','$2'...]}. %% repeat -> repeat "*" : {kclosure,'$1'}. %% repeat -> repeat "+" : {pclosure,'$1'}. %% repeat -> repeat "?" : {optional,'$1'}. %% repeat -> repeat "{" [Min],[Max] "}" : {interval,'$1',Min,Max} %% repeat -> single : '$1'. %% single -> "(" reg ")" : {sub,'$2',Number}. %% single -> "^" : bos/bol. %% single -> "$" : eos/eol. %% single -> "." : any. %% single -> "[" class "]" : {char_class,char_class('$2')} %% single -> "[" "^" class "]" : {comp_class,char_class('$3')}. %% single -> "\"" chars "\"" : {lit,'$2'}. %% single -> "\\" char : {lit,['$2']}. %% single -> char : {lit,['$1']}. %% single -> empty : epsilon. %% The grammar of the current regular expressions. The actual parser %% is a recursive descent implementation of the grammar. %% re_parse(Chars, State) -> {ok,RegExp} | {error,Error}. re_parse(Cs0, St) -> case catch re_reg(Cs0, 0, St) of {RE,_,[]} -> {ok,RE}; {_,_,[C|_]} -> {error,{illegal_char,[C]}}; {parse_error,E} -> {error,E} end. parse_error(E) -> throw({parse_error,E}). re_reg(Cs, Sn, St) -> re_alt(Cs, Sn, St). re_alt(Cs0, Sn0, St) -> {L,Sn1,Cs1} = re_seq(Cs0, Sn0, St), case re_alt1(Cs1, Sn1, St) of {[],Sn2,Cs2} -> {L,Sn2,Cs2}; {Rs,Sn2,Cs2} -> {{alt,[L|Rs]},Sn2,Cs2} end. re_alt1([$||Cs0], Sn0, St) -> {L,Sn1,Cs1} = re_seq(Cs0, Sn0, St), {Rs,Sn2,Cs2} = re_alt1(Cs1, Sn1, St), {[L|Rs],Sn2,Cs2}; re_alt1(Cs, Sn, _) -> {[],Sn,Cs}. %% Parse a sequence of regexps. Don't allow the empty sequence. %% re_seq(Cs0, Sn0, St) -> %% {L,Sn1,Cs1} = repeat(Cs0, Sn0, St), %% case re_seq1(Cs1, Sn1, St) of %% {[],Sn2,Cs2} -> {L,Sn2,Cs2}; %% {Rs,Sn2,Cs2} -> {{seq,[L|Rs]},Sn2,Cs2} %% end. %% re_seq(Chars, SubNumber, State) -> {RegExp,SubNumber,Chars}. %% Parse a sequence of regexps. Allow the empty sequence, returns epsilon. re_seq(Cs0, Sn0, St) -> case re_seq1(Cs0, Sn0, St) of {[],Sn1,Cs1} -> {epsilon,Sn1,Cs1}; {[R],Sn1,Cs1} -> {R,Sn1,Cs1}; {Rs,Sn1,Cs1} -> {{seq,Rs},Sn1,Cs1} end. re_seq1([C|_]=Cs0, Sn0, St) when C =/= $|, C =/= $) -> {L,Sn1,Cs1} = re_repeat(Cs0, Sn0, St), {Rs,Sn2,Cs2} = re_seq1(Cs1, Sn1, St), {[L|Rs],Sn2,Cs2}; re_seq1(Cs, Sn, _) -> {[],Sn,Cs}. %% re_repeat(Chars, SubNumber, State) -> {RegExp,SubNumber,Chars}. re_repeat(Cs0, Sn0, St) -> {S,Sn1,Cs1} = re_single(Cs0, Sn0, St), re_repeat1(Cs1, Sn1, S, St). re_repeat1([$*|Cs], Sn, S, St) -> re_repeat1(Cs, Sn, {kclosure,S}, St); re_repeat1([$+|Cs], Sn, S, St) -> re_repeat1(Cs, Sn, {pclosure,S}, St); re_repeat1([$?|Cs], Sn, S, St) -> re_repeat1(Cs, Sn, {optional,S}, St); %% { only starts interval when ere is true, otherwise normal character. %% re_repeat1([${|Cs0], Sn, S, #leex{posix=true}=St) -> % $} %% case re_interval_range(Cs0) of %% {Min,Max,[$}|Cs1]} when is_integer(Min), is_integer(Max), Min =< Max -> %% re_repeat1(Cs1, Sn, {interval,S,Min,Max}, St); %% {Min,Max,[$}|Cs1]} when is_integer(Min), is_atom(Max) -> %% re_repeat1(Cs1, Sn, {interval,S,Min,Max}, St); %% {_,_,Cs1} -> parse_error({interval_range,string_between([${|Cs0], Cs1)}) %% end; re_repeat1(Cs, Sn, S, _) -> {S,Sn,Cs}. %% re_single(Chars, SubNumber, State) -> {RegExp,SubNumber,Chars}. %% Parse a re_single regexp. re_single([$(|Cs0], Sn0, St) -> % $) Sn1 = Sn0 + 1, % Keep track of sub count anyway case re_reg(Cs0, Sn1, St) of {S,Sn2,[$)|Cs1]} -> {S,Sn2,Cs1}; %%{S,Sn2,[$)|Cs1]} -> {{sub,S,Sn1},Sn2,Cs1}; _ -> parse_error({unterminated,"("}) end; %% These are not legal inside a regexp. %% re_single([$^|Cs], Sn, St) -> {bos,Sn,Cs}; %% re_single([$$|Cs], Sn, St) -> {eos,Sn,Cs}; %% re_single([$.|Cs], Sn, St) -> {any,Sn,Cs}; re_single([$.|Cs], Sn, _) -> {{comp_class,"\n"},Sn,Cs}; % Do this here? re_single("[^" ++ Cs0, Sn, St) -> case re_char_class(Cs0, St) of {Cc,[$]|Cs1]} -> {{comp_class,Cc},Sn,Cs1}; _ -> parse_error({unterminated,"["}) end; re_single([$[|Cs0], Sn, St) -> case re_char_class(Cs0, St) of {Cc,[$]|Cs1]} -> {{char_class,Cc},Sn,Cs1}; _ -> parse_error({unterminated,"["}) end; re_single([$\\|Cs0], Sn, _) -> {C,Cs1} = re_char($\\, Cs0), {{lit,[C]},Sn,Cs1}; re_single([C|Cs0], Sn, St) -> case special_char(C, St) of true -> parse_error({illegal_char,[C]}); false -> {C,Cs1} = re_char(C, Cs0), {{lit,[C]},Sn,Cs1} end. -define(IS_HEX(C), C >= $0 andalso C =< $9 orelse C >= $A andalso C =< $F orelse C >= $a andalso C =< $f). %% re_char(Char, Chars) -> {CharValue,Chars}. %% Reads one character value from the input list, it knows about escapes. re_char($\\, [O1,O2,O3|S]) when O1 >= $0, O1 =< $7, O2 >= $0, O2 =< $7, O3 >= $0, O3 =< $7 -> {(O1*8 + O2)*8 + O3 - 73*$0,S}; re_char($\\, [$x,H1,H2|S]) when ?IS_HEX(H1), ?IS_HEX(H2) -> {erlang:list_to_integer([H1,H2], 16),S}; re_char($\\,[$x,${|S0]) -> re_hex(S0, []); re_char($\\,[$x|_]) -> parse_error({illegal_char,"\\x"}); re_char($\\, [C|S]) -> {escape_char(C),S}; re_char($\\, []) -> parse_error({unterminated,"\\"}); re_char(C, S) -> {C,S}. % Just this character re_hex([C|Cs], L) when ?IS_HEX(C) -> re_hex(Cs, [C|L]); re_hex([$}|S], L0) -> L = lists:reverse(L0), case erlang:list_to_integer(L, 16) of C when C =< 16#10FFFF -> {C,S}; _ -> parse_error({illegal_char,[$\\,$x,${|L]++"}"}) end; re_hex(_, _) -> parse_error({unterminated,"\\x{"}). %% special_char(Char, State) -> bool(). %% These are the special characters for an ERE. %% N.B. ]}) are only special in the context after [{(. special_char($^, _) -> true; special_char($., _) -> true; special_char($[, _) -> true; special_char($$, _) -> true; special_char($(, _) -> true; special_char($), _) -> true; special_char($|, _) -> true; special_char($*, _) -> true; special_char($+, _) -> true; special_char($?, _) -> true; %% special_char(${, #leex{posix=true}) -> true; % Only when POSIX set special_char($\\, _) -> true; special_char(_, _) -> false. %% re_char_class(Chars, State) -> {CharClass,Chars}. %% Parse a character class. re_char_class([$]|Cs], St) -> % Must special case this. re_char_class(Cs, [$]], St); re_char_class(Cs, St) -> re_char_class(Cs, [], St). %% re_char_class("[:" ++ Cs0, Cc, #leex{posix=true}=St) -> %% %% POSIX char class only. %% case posix_cc(Cs0) of %% {Pcl,":]" ++ Cs1} -> re_char_class(Cs1, [{posix,Pcl}|Cc], St); %% {_,Cs1} -> parse_error({posix_cc,string_between(Cs0, Cs1)}) %% end; re_char_class([C1|Cs0], Cc, St) when C1 =/= $] -> case re_char(C1, Cs0) of {Cf,[$-,C2|Cs1]} when C2 =/= $] -> case re_char(C2, Cs1) of {Cl,Cs2} when Cf < Cl -> re_char_class(Cs2, [{range,Cf,Cl}|Cc], St); {_,Cs2} -> parse_error({char_class,string_between([C1|Cs0], Cs2)}) end; {C,Cs1} -> re_char_class(Cs1, [C|Cc], St) end; re_char_class(Cs, Cc, _) -> {reverse(Cc),Cs}. % Preserve order %% posix_cc(String) -> {PosixClass,RestString}. %% Handle POSIX character classes. %% posix_cc("alnum" ++ Cs) -> {alnum,Cs}; %% posix_cc("alpha" ++ Cs) -> {alpha,Cs}; %% posix_cc("blank" ++ Cs) -> {blank,Cs}; %% posix_cc("cntrl" ++ Cs) -> {cntrl,Cs}; %% posix_cc("digit" ++ Cs) -> {digit,Cs}; %% posix_cc("graph" ++ Cs) -> {graph,Cs}; %% posix_cc("lower" ++ Cs) -> {lower,Cs}; %% posix_cc("print" ++ Cs) -> {print,Cs}; %% posix_cc("punct" ++ Cs) -> {punct,Cs}; %% posix_cc("space" ++ Cs) -> {space,Cs}; %% posix_cc("upper" ++ Cs) -> {upper,Cs}; %% posix_cc("xdigit" ++ Cs) -> {xdigit,Cs}; %% posix_cc(Cs) -> parse_error({posix_cc,string:slice(Cs, 0, 5)}). escape_char($n) -> $\n; % \n = LF escape_char($r) -> $\r; % \r = CR escape_char($t) -> $\t; % \t = TAB escape_char($v) -> $\v; % \v = VT escape_char($b) -> $\b; % \b = BS escape_char($f) -> $\f; % \f = FF escape_char($e) -> $\e; % \e = ESC escape_char($s) -> $\s; % \s = SPACE escape_char($d) -> $\d; % \d = DEL escape_char(C) -> C. % Pass it straight through %% re_interval_range(Chars) -> {Min,Max,RestChars}. %% NoInt -> none,none %% Int -> Int,none %% Int, -> Int,any %% Int1,Int2 -> Int1,Int2 %% re_interval_range(Cs0) -> %% case re_number(Cs0) of %% {none,Cs1} -> {none,none,Cs1}; %% {N,[$,|Cs1]} -> %% case re_number(Cs1) of %% {none,Cs2} -> {N,any,Cs2}; %% {M,Cs2} -> {N,M,Cs2} %% end; %% {N,Cs1} -> {N,none,Cs1} %% end. %% re_number([C|Cs]) when C >= $0, C =< $9 -> %% re_number(Cs, C - $0); %% re_number(Cs) -> {none,Cs}. %% re_number([C|Cs], Acc) when C >= $0, C =< $9 -> %% re_number(Cs, 10*Acc + (C - $0)); %% re_number(Cs, Acc) -> {Acc,Cs}. string_between(Cs1, Cs2) -> string:slice(Cs1, 0, string:length(Cs1)-string:length(Cs2)). %% We use standard methods, Thompson's construction and subset %% construction, to create first an NFA and then a DFA from the %% regexps. A non-standard feature is that we work with sets of %% character ranges (crs) instead sets of characters. This is most %% noticeable when constructing DFAs. The major benefit is that we can %% handle characters from any set, not just limited ASCII or 8859, %% even 16/32 bit unicode. %% %% The whole range of characters is 0-maxchar, where maxchar is a BIG %% number. We don't make any assumptions about the size of maxchar, it %% is just bigger than any character. %% %% Using character ranges makes describing many regexps very simple, %% for example the regexp "." just becomes the range %% [{0-9},{11-maxchar}]. %% make_nfa(RegExpActions) -> {ok,{NFA,StartState}} | {error,E}. %% Build a complete nfa from a list of {RegExp,Action}. The NFA field %% accept has values {yes,Action}|no. The NFA is a list of states. make_dfa(REAs, St) -> {NFA,NF} = build_combined_nfa(REAs), verbose_print(St, "NFA contains ~w states, ", [tuple_size(NFA)]), {DFA0,DF0} = build_dfa(NFA, NF), verbose_print(St, "DFA contains ~w states, ", [length(DFA0)]), {DFA,DF} = minimise_dfa(DFA0, DF0), verbose_print(St, "minimised to ~w states.~n", [length(DFA)]), %%io:fwrite("~p\n", [{NF,NFA}]), %%io:fwrite("~p\n", [{DF0,DFA0}]), %%io:fwrite("~p\n", [{DF,DFA}]), {DFA,DF}. %% build_combined_nfa(RegExpActionList) -> {NFA,FirstState}. %% Build the combined NFA using Thompson's construction straight out %% of the book. Build the separate NFAs in the same order as the %% rules so that the accepting have ascending states have ascending %% state numbers. Start numbering the states from 1 as we put the %% states in a tuple with the state number as the index. %% %% The edges from a state are a list of {CharRange,State} | {epsilon,State}. build_combined_nfa(REAs) -> {NFA0,Firsts,Free} = build_nfa_list(REAs, [], [], 1), F = #nfa_state{no=Free,edges=epsilon_trans(Firsts)}, {list_to_tuple(keysort(#nfa_state.no, [F|NFA0])),Free}. build_nfa_list([{RE,Action}|REAs], NFA0, Firsts, Free0) -> {NFA1,Free1,First} = build_nfa(RE, Free0, Action), build_nfa_list(REAs, NFA1 ++ NFA0, [First|Firsts], Free1); build_nfa_list([], NFA, Firsts, Free) -> {NFA,reverse(Firsts),Free}. epsilon_trans(Firsts) -> [ {epsilon,F} || F <- Firsts ]. %% build_nfa(RegExp, NextState, Action) -> {NFA,NextState,FirstState}. %% When building the NFA states for a regexp we don't build the end %% state, just allocate a State for it and return this state's %% number. This allows us to avoid building unnecessary states for %% concatenation which would then have to be removed by overwriting %% an existing state. build_nfa(RE, N0, Action) -> {NFA,N1,E} = build_nfa(RE, N0+1, N0, []), {[#nfa_state{no=E,accept={accept,Action}}|NFA],N1,N0}. %% build_nfa(RegExp, NextState, FirstState, NFA) -> {NFA,NextState,EndState}. %% Build an NFA from the RegExp. NFA is a list of #nfa_state{} in no %% predefined order. NextState is the number of the next free state %% to use, FirstState is the the state which must be the start for %% this regexp as a previous regexp refers to it, EndState is the %% state to which this NFA will exit to. The number of the returned %% EndState is already allocated! build_nfa({alt,REs}, N, F, NFA) -> build_nfa_alt(REs, N, F, NFA); build_nfa({seq,REs}, N, F, NFA) -> build_nfa_seq(REs, N, F, NFA); build_nfa({kclosure,RE}, N0, F, NFA0) -> {NFA1,N1,E1} = build_nfa(RE, N0+1, N0, NFA0), E = N1, % End state {[#nfa_state{no=F,edges=[{epsilon,N0},{epsilon,E}]}, #nfa_state{no=E1,edges=[{epsilon,N0},{epsilon,E}]}|NFA1], N1+1,E}; build_nfa({pclosure,RE}, N0, F, NFA0) -> {NFA1,N1,E1} = build_nfa(RE, N0+1, N0, NFA0), E = N1, % End state {[#nfa_state{no=F,edges=[{epsilon,N0}]}, #nfa_state{no=E1,edges=[{epsilon,N0},{epsilon,E}]}|NFA1], N1+1,E}; build_nfa({optional,RE}, N0, F, NFA0) -> {NFA1,N1,E1} = build_nfa(RE, N0+1, N0, NFA0), E = N1, % End state {[#nfa_state{no=F,edges=[{epsilon,N0},{epsilon,E}]}, #nfa_state{no=E1,edges=[{epsilon,E}]}|NFA1], N1+1,E}; build_nfa({char_class,Cc}, N, F, NFA) -> {[#nfa_state{no=F,edges=[{pack_cc(Cc),N}]}|NFA],N+1,N}; build_nfa({comp_class,Cc}, N, F, NFA) -> {[#nfa_state{no=F,edges=[{comp_class(Cc),N}]}|NFA],N+1,N}; build_nfa({lit,Cs}, N, F, NFA) -> % Implicit concatenation build_nfa_lit(Cs, N, F, NFA); build_nfa(epsilon, N, F, NFA) -> % Just an epsilon transition {[#nfa_state{no=F,edges=[{epsilon,N}]}|NFA],N+1,N}. %% build_nfa_lit(Chars, NextState, FirstState, NFA) -> {NFA,NextState,EndState}. %% Build an NFA for the sequence of literal characters. build_nfa_lit(Cs, N0, F0, NFA0) -> foldl(fun (C, {NFA,N,F}) -> {[#nfa_state{no=F,edges=[{[{C,C}],N}]}|NFA],N+1,N} end, {NFA0,N0,F0}, Cs). %% build_nfa_lit([C|Cs], N, F, NFA0) when is_integer(C) -> %% NFA1 = [#nfa_state{no=F,edges=[{[{C,C}],N}]}|NFA0], %% build_nfa_lit(Cs, N+1, N, NFA1); %% build_nfa_lit([], N, F, NFA) -> {NFA,N,F}. %% build_nfa_seq(REs, NextState, FirstState, NFA) -> {NFA,NextState,EndState}. %% Build an NFA for the regexps in a sequence. build_nfa_seq(REs, N0, F0, NFA0) -> foldl(fun (RE, {NFA,N,F}) -> build_nfa(RE, N, F, NFA) end, {NFA0,N0,F0}, REs). %% build_nfa_seq([RE|REs], N0, F, NFA0) -> %% {NFA1,N1,E1} = build_nfa(RE, N0, F, NFA0), %% build_nfa_seq(REs, N1, E1, NFA1); %% build_nfa_seq([], N, F, NFA) -> {NFA,N,F}. %% build_nfa_alt(REs, NextState, FirstState, NFA) -> {NFA,NextState,EndState}. %% Build an NFA for the regexps in an alternative. N.B. we don't %% handle empty alts here but the parser should never generate them %% anyway. build_nfa_alt([RE], N, F, NFA) -> build_nfa(RE, N, F, NFA); build_nfa_alt([RE|REs], N0, F, NFA0) -> {NFA1,N1,E1} = build_nfa(RE, N0+1, N0, NFA0), {NFA2,N2,E2} = build_nfa_alt(REs, N1+1, N1, NFA1), E = N2, % End state {[#nfa_state{no=F,edges=[{epsilon,N0},{epsilon,N1}]}, #nfa_state{no=E1,edges=[{epsilon,E}]}, #nfa_state{no=E2,edges=[{epsilon,E}]}|NFA2], N2+1,E}. %% build_nfa_alt(REs, NextState, FirstState, NFA) -> {NFA,NextState,EndState}. %% Build an NFA for the regexps in an alternative. Make one big %% epsilon split state, not necessary but fun. %% build_nfa_alt(REs, N0, F0, NFA0) -> %% E = N0, % Must reserve End state first %% {Fs,{NFA1,N1}} = mapfoldl(fun (RE, {NFA,N}) -> %% build_nfa_alt1(RE, N, E, NFA) %% end, {NFA0,N0+1}, REs), %% {[#nfa_state{no=F0,edges=epsilon_trans(Fs)}, %% #nfa_state{no=E,edges=[{epsilon,N1}]}|NFA1],N1+1,N1}. %% build_nfa_alt1(RE, N0, End, NFA0) -> %% {NFA1,N1,E} = build_nfa(RE, N0+1, N0, NFA0), %% {N0,{[#nfa_state{no=E,edges=[{epsilon,End}]}|NFA1],N1}}. %% pack_cc(CharClass) -> CharClass %% Pack and optimise a character class specification (bracket %% expression). First sort it and then compact it. pack_cc(Cc) -> Crs = foldl(fun ({range,Cf,Cl}, Set) -> add_element({Cf,Cl}, Set); (C, Set) -> add_element({C,C}, Set) end, ordsets:new(), Cc), pack_crs(Crs). % An ordset IS a list! pack_crs([{C1,C2}=Cr,{C3,C4}|Crs]) when C1 =< C3, C2 >= C4 -> %% C1 C2 %% C3 C4 pack_crs([Cr|Crs]); pack_crs([{C1,C2},{C3,C4}|Crs]) when C2 >= C3, C2 < C4 -> %% C1 C2 %% C3 C4 pack_crs([{C1,C4}|Crs]); pack_crs([{C1,C2},{C3,C4}|Crs]) when C2 + 1 =:= C3 -> %% C1 C2 %% C3 C4 pack_crs([{C1,C4}|Crs]); pack_crs([Cr|Crs]) -> [Cr|pack_crs(Crs)]; pack_crs([]) -> []. comp_class(Cc) -> Crs = pack_cc(Cc), Comp = comp_crs(Crs, 0), %% io:fwrite("comp: ~p\n ~p\n", [Crs,Comp]), Comp. comp_crs([{0,C2}|Crs], 0) -> % Get first range right comp_crs(Crs, C2+1); comp_crs([{C1,C2}|Crs], Last) -> [{Last,C1-1}|comp_crs(Crs, C2+1)]; comp_crs([], Last) -> [{Last,maxchar}]. %% build_dfa(NFA, NfaFirstState) -> {DFA,DfaFirstState}. %% Build a DFA from an NFA using "subset construction". The major %% difference from the book is that we keep the marked and unmarked %% DFA states in seperate lists. New DFA states are added to the %% unmarked list and states are marked by moving them to the marked %% list. We assume that the NFA accepting state numbers are in %% ascending order for the rules and use ordsets to keep this order. build_dfa(NFA, Nf) -> D = #dfa_state{no=0,nfa=eclosure([Nf], NFA)}, {build_dfa([D], 1, [], NFA),0}. %% build_dfa([UnMarked], NextState, [Marked], NFA) -> DFA. %% Traverse the unmarked states. Temporarily add the current unmarked %% state to the marked list before calculating translation, this is %% to avoid adding too many duplicate states. Add it properly to the %% marked list afterwards with correct translations. build_dfa([U|Us0], N0, Ms, NFA) -> {Ts,Us1,N1} = build_dfa(U#dfa_state.nfa, Us0, N0, [], [U|Ms], NFA), M = U#dfa_state{trans=Ts,accept=accept(U#dfa_state.nfa, NFA)}, build_dfa(Us1, N1, [M|Ms], NFA); build_dfa([], _, Ms, _) -> Ms. %% build_dfa([NfaState], [Unmarked], NextState, [Transition], [Marked], NFA) -> %% {Transitions,UnmarkedStates,NextState}. %% Foreach NFA state set calculate the legal translations. N.B. must %% search *BOTH* the unmarked and marked lists to check if DFA state %% already exists. As the range of characters is potentially VERY %% large we cannot explicitly test all characters. Instead we first %% calculate the set of all disjoint character ranges which are %% possible candidates to the set of NFA states. The transitions are %% an orddict so we get the transition lists in ascending order. build_dfa(Set, Us, N, Ts, Ms, NFA) -> %% List of all transition sets. Crs0 = [Cr || S <- Set, {Crs,_St} <- (element(S, NFA))#nfa_state.edges, Crs =/= epsilon, % Not an epsilon transition Cr <- Crs ], Crs1 = lists:usort(Crs0), % Must remove duplicates! %% Build list of disjoint test ranges. Test = disjoint_crs(Crs1), %% io:fwrite("bd: ~p\n ~p\n ~p\n ~p\n", [Set,Crs0,Crs1,Test]), build_dfa(Test, Set, Us, N, Ts, Ms, NFA). %% disjoint_crs([CharRange]) -> [CharRange]. %% Take a sorted list of char ranges and make a sorted list of %% disjoint char ranges. No new char range extends past an existing %% char range. disjoint_crs([{_C1,C2}=Cr1,{C3,_C4}=Cr2|Crs]) when C2 < C3 -> %% C1 C2 %% C3 C4 [Cr1|disjoint_crs([Cr2|Crs])]; disjoint_crs([{C1,C2},{C3,C4}|Crs]) when C1 =:= C3 -> %% C1 C2 %% C3 C4 [{C1,C2}|disjoint_crs(add_element({C2+1,C4}, Crs))]; disjoint_crs([{C1,C2},{C3,C4}|Crs]) when C1 < C3, C2 >= C3, C2 < C4 -> %% C1 C2 %% C3 C4 [{C1,C3-1}|disjoint_crs(union([{C3,C2},{C2+1,C4}], Crs))]; disjoint_crs([{C1,C2},{C3,C4}|Crs]) when C1 < C3, C2 =:= C4 -> %% C1 C2 %% C3 C4 [{C1,C3-1}|disjoint_crs(add_element({C3,C4}, Crs))]; disjoint_crs([{C1,C2},{C3,C4}|Crs]) when C1 < C3, C2 > C4 -> %% C1 C2 %% C3 C4 [{C1,C3-1}|disjoint_crs(union([{C3,C4},{C4+1,C2}], Crs))]; disjoint_crs([Cr|Crs]) -> [Cr|disjoint_crs(Crs)]; disjoint_crs([]) -> []. build_dfa([Cr|Crs], Set, Us, N, Ts, Ms, NFA) -> case eclosure(move(Set, Cr, NFA), NFA) of S when S =/= [] -> case dfa_state_exist(S, Us, Ms) of {yes,T} -> build_dfa(Crs, Set, Us, N, store(Cr, T, Ts), Ms, NFA); no -> U = #dfa_state{no=N,nfa=S}, build_dfa(Crs, Set, [U|Us], N+1, store(Cr, N, Ts), Ms, NFA) end; [] -> build_dfa(Crs, Set, Us, N, Ts, Ms, NFA) end; build_dfa([], _, Us, N, Ts, _, _) -> {Ts,Us,N}. %% dfa_state_exist(Set, Unmarked, Marked) -> {yes,State} | no. dfa_state_exist(S, Us, Ms) -> case lists:keyfind(S, #dfa_state.nfa, Us) of #dfa_state{no=T} -> {yes,T}; false -> case lists:keyfind(S, #dfa_state.nfa, Ms) of #dfa_state{no=T} -> {yes,T}; false -> no end end. %% eclosure([State], NFA) -> [State]. %% move([State], Char, NFA) -> [State]. %% These are straight out of the book. As eclosure uses ordsets then %% the generated state sets are in ascending order. eclosure(Sts, NFA) -> eclosure(Sts, NFA, []). eclosure([St|Sts], NFA, Ec) -> #nfa_state{edges=Es} = element(St, NFA), eclosure([ N || {epsilon,N} <- Es, not is_element(N, Ec) ] ++ Sts, NFA, add_element(St, Ec)); eclosure([], _, Ec) -> Ec. move(Sts, Cr, NFA) -> %% io:fwrite("move1: ~p\n", [{Sts,Cr}]), [ St || N <- Sts, {Crs,St} <- (element(N, NFA))#nfa_state.edges, Crs =/= epsilon, % Not an epsilon transition in_crs(Cr, Crs) ]. in_crs({C1,C2}, [{C3,C4}|_Crs]) when C1 >= C3, C2 =< C4 -> true; in_crs(Cr, [Cr|_Crs]) -> true; % Catch bos and eos. in_crs(Cr, [_|Crs]) -> in_crs(Cr, Crs); in_crs(_Cr, []) -> false. %% accept([State], NFA) -> {accept,A} | noaccept. %% Scan down the state list until we find an accepting state. accept([St|Sts], NFA) -> case element(St, NFA) of #nfa_state{accept={accept,A}} -> {accept,A}; #nfa_state{accept=noaccept} -> accept(Sts, NFA) end; accept([], _) -> noaccept. %% minimise_dfa(DFA, DfaFirst) -> {DFA,DfaFirst}. %% Minimise the DFA by removing equivalent states. We consider a %% state if both the transitions and the their accept state is the %% same. First repeatedly run throught the DFA state list removing %% equivalent states and updating remaining transitions with %% remaining equivalent state numbers. When no more reductions are %% possible then pack the remaining state numbers to get consecutive %% states. minimise_dfa(DFA0, Df0) -> case min_dfa(DFA0) of {DFA1,[]} -> % No reduction! {DFA2,Rs} = pack_dfa(DFA1), {min_update(DFA2, Rs),min_use(Df0, Rs)}; {DFA1,Rs} -> minimise_dfa(min_update(DFA1, Rs), min_use(Df0, Rs)) end. min_dfa(DFA) -> min_dfa(DFA, [], []). min_dfa([D|DFA0], Rs0, MDFA) -> {DFA1,Rs1} = min_delete(DFA0, D#dfa_state.trans, D#dfa_state.accept, D#dfa_state.no, Rs0, []), min_dfa(DFA1, Rs1, [D|MDFA]); min_dfa([], Rs, MDFA) -> {MDFA,Rs}. %% min_delete(States, Trans, Action, NewN, Rs, MiniDFA) -> {MiniDFA,Rs}. %% Delete all states with same transactions and action. Return %% rewrites and minimised DFA with no duplicate states. min_delete([#dfa_state{no=N,trans=T,accept=A}|DFA], T, A, NewN, Rs, MDFA) -> min_delete(DFA, T, A, NewN, [{N,NewN}|Rs], MDFA); min_delete([D|DFA], T, A, NewN, Rs, MDFA) -> min_delete(DFA, T, A, NewN, Rs, [D|MDFA]); min_delete([], _, _, _, Rs, MDFA) -> {MDFA,Rs}. min_update(DFA, Rs) -> [ D#dfa_state{trans=min_update_trans(D#dfa_state.trans, Rs)} || D <- DFA ]. min_update_trans(Tr, Rs) -> [ {C,min_use(S, Rs)} || {C,S} <- Tr ]. min_use(Old, [{Old,New}|_]) -> New; min_use(Old, [_|Reds]) -> min_use(Old, Reds); min_use(Old, []) -> Old. pack_dfa(DFA) -> pack_dfa(DFA, 0, [], []). pack_dfa([D|DFA], NewN, Rs, PDFA) -> pack_dfa(DFA, NewN+1, [{D#dfa_state.no,NewN}|Rs], [D#dfa_state{no=NewN}|PDFA]); pack_dfa([], _, Rs, PDFA) -> {PDFA,Rs}. %% The main output is the yystate function which is built from the %% DFA. It has the spec: %% %% yystate() -> InitialState. %% yystate(State, InChars, Line, CurrTokLen, AcceptAction, AcceptLen) -> %% {Action, AcceptLength, RestChars, Line} | Accepting end state %% {Action, AcceptLength, RestChars, Line, State} | Accepting state %% {reject, AcceptLength, CurrTokLen, RestChars, Line, State} | %% {Action, AcceptLength, CurrTokLen, RestChars, Line, State}. %% The return CurrTokLen is always the current number of characters %% scanned in the current token. The returns have the following %% meanings: %% {Action, AcceptLength, RestChars, Line} - %% The scanner has reached an accepting end-state, for example after %% a regexp "abc". Action is the action number and AcceptLength is %% the length of the matching token. %% %% {Action, AcceptLength, RestChars, Line, State} - %% The scanner has reached an accepting transition state, for example %% after c in regexp "abc(xyz)?", continuation depends on %% RestChars. If RestChars == [] (no more current characters) then we %% need to get more characters to see if it is an end-state, %% otherwise (eof or chars) then we have not found continuing %% characters and it is an end state. %% %% {reject, AcceptLength, CurrTokLen, RestChars, Line, State} - %% {Action, AcceptLength, CurrTokLen, RestChars, Line, State} - %% The scanner has reached a non-accepting transition state. If %% RestChars == [] we need to get more characters to continue. %% Otherwise if 'reject' then no accepting state has been reached it %% is an error. If we have an Action and AcceptLength then these are %% the last accept state, use them and continue from there. %% out_file(LeexState, DFA, DfaStart, [Action], Code) -> ok | error. %% Generate an output .erl file from the include file, the DFA and %% the code for the actions. out_file(St0, DFA, DF, Actions, Code) -> verbose_print(St0, "Writing file ~ts, ", [St0#leex.efile]), case open_inc_file(St0) of {ok,Ifile} -> try case file:open(St0#leex.efile, [write]) of {ok,Ofile} -> set_encoding(St0, Ofile), try output_encoding_comment(Ofile, St0), output_file_directive(Ofile, St0#leex.ifile, 0), out_file(Ifile, Ofile, St0, DFA, DF, Actions, Code, 1), verbose_print(St0, "ok~n", []), St0 after ok = file:close(Ofile) end; {error,Error} -> verbose_print(St0, "error~n", []), add_error({none,leex,{file_error,Error}}, St0) end after ok = file:close(Ifile) end; {{error,Error},Ifile} -> add_error(Ifile, {none,leex,{file_error,Error}}, St0) end. open_inc_file(State) -> Ifile = State#leex.ifile, case file:open(Ifile, [read]) of {ok,F} -> _ = epp:set_encoding(F), {ok,F}; Error -> {Error,Ifile} end. inc_file_name([]) -> Incdir = filename:join(code:lib_dir(parsetools), "include"), filename:join(Incdir, ?LEEXINC); inc_file_name(Filename) -> Filename. %% out_file(IncFile, OutFile, State, DFA, DfaStart, Actions, Code, Line) -> ok %% Copy the include file line by line substituting special lines with %% generated code. We cheat by only looking at the first 5 %% characters. out_file(Ifile, Ofile, St, DFA, DF, Actions, Code, L) -> case io:get_line(Ifile, leex) of eof -> output_file_directive(Ofile, St#leex.ifile, L); {error, _} -> add_error(St#leex.ifile, {L, leex, cannot_parse}, St); Line -> case string:slice(Line, 0, 5) of "##mod" -> out_module(Ofile, St); "##cod" -> out_erlang_code(Ofile, St, Code, L); "##dfa" -> out_dfa(Ofile, St, DFA, Code, DF, L); "##act" -> out_actions(Ofile, St#leex.xfile, Actions); _ -> io:put_chars(Ofile, Line) end, out_file(Ifile, Ofile, St, DFA, DF, Actions, Code, L+1) end. out_module(File, St) -> io:fwrite(File, "-module(~w).\n", [St#leex.module]). out_erlang_code(File, St, Code, L) -> {CodeL,CodePos,_NCodeLines} = Code, output_file_directive(File, St#leex.xfile, CodeL), {ok,Xfile} = file:open(St#leex.xfile, [read]), try set_encoding(St, Xfile), {ok,_} = file:position(Xfile, CodePos), ok = file_copy(Xfile, File) after ok = file:close(Xfile) end, io:nl(File), output_file_directive(File, St#leex.ifile, L). file_copy(From, To) -> case io:get_line(From, leex) of eof -> ok; Line when is_list(Line) -> io:fwrite(To, "~ts", [Line]), file_copy(From, To) end. out_dfa(File, St, DFA, Code, DF, L) -> {_CodeL,_CodePos,NCodeLines} = Code, %% Three file attributes before this one... output_file_directive(File, St#leex.efile, L+(NCodeLines-1)+3), io:fwrite(File, "yystate() -> ~w.~n~n", [DF]), foreach(fun (S) -> out_trans(File, S) end, DFA), io:fwrite(File, "yystate(S, Ics, Line, Tlen, Action, Alen) ->~n", []), io:fwrite(File, " {Action,Alen,Tlen,Ics,Line,S}.~n", []). out_trans(File, #dfa_state{no=N,trans=[],accept={accept,A}}) -> %% Accepting end state, guaranteed done. io:fwrite(File, "yystate(~w, Ics, Line, Tlen, _, _) ->~n", [N]), io:fwrite(File, " {~w,Tlen,Ics,Line};~n", [A]); out_trans(File, #dfa_state{no=N,trans=Tr,accept={accept,A}}) -> %% Accepting state, but there maybe more. foreach(fun (T) -> out_accept_tran(File, N, A, T) end, pack_trans(Tr)), io:fwrite(File, "yystate(~w, Ics, Line, Tlen, _, _) ->~n", [N]), io:fwrite(File, " {~w,Tlen,Ics,Line,~w};~n", [A,N]); out_trans(File, #dfa_state{no=N,trans=Tr,accept=noaccept}) -> %% Non-accepting transition state. foreach(fun (T) -> out_noaccept_tran(File, N, T) end, pack_trans(Tr)), io:fwrite(File, "yystate(~w, Ics, Line, Tlen, Action, Alen) ->~n", [N]), io:fwrite(File, " {Action,Alen,Tlen,Ics,Line,~w};~n", [N]). out_accept_tran(File, N, A, {{Cf,maxchar},S}) -> out_accept_head_max(File, N, Cf), out_accept_body(File, S, "Line", A); out_accept_tran(File, N, A, {{Cf,Cl},S}) -> out_accept_head_range(File, N, Cf, Cl), out_accept_body(File, S, "Line", A); out_accept_tran(File, N, A, {$\n,S}) -> out_accept_head_1(File, N, $\n), out_accept_body(File, S, "Line+1", A); out_accept_tran(File, N, A, {C,S}) -> out_accept_head_1(File, N, C), out_accept_body(File, S, "Line", A). out_accept_head_1(File, State, Char) -> out_head_1(File, State, Char, "_", "_"). out_accept_head_max(File, State, Min) -> out_head_max(File, State, Min, "_", "_"). out_accept_head_range(File, State, Min, Max) -> out_head_range(File, State, Min, Max, "_", "_"). out_accept_body(File, Next, Line, Action) -> out_body(File, Next, Line, io_lib:write(Action), "Tlen"). out_noaccept_tran(File, N, {{Cf,maxchar},S}) -> out_noaccept_head_max(File, N, Cf), out_noaccept_body(File, S, "Line"); out_noaccept_tran(File, N, {{Cf,Cl},S}) -> out_noaccept_head_range(File, N, Cf, Cl), out_noaccept_body(File, S, "Line"); out_noaccept_tran(File, N, {$\n,S}) -> out_noaccept_head_1(File, N, $\n), out_noaccept_body(File, S, "Line+1"); out_noaccept_tran(File, N, {C,S}) -> out_noaccept_head_1(File, N, C), out_noaccept_body(File, S, "Line"). out_noaccept_head_1(File, State, Char) -> out_head_1(File, State, Char, "Action", "Alen"). out_noaccept_head_max(File, State, Min) -> out_head_max(File, State, Min, "Action", "Alen"). out_noaccept_head_range(File, State, Min, Max) -> out_head_range(File, State, Min, Max, "Action", "Alen"). out_noaccept_body(File, Next, Line) -> out_body(File, Next, Line, "Action", "Alen"). out_head_1(File, State, Char, Action, Alen) -> io:fwrite(File, "yystate(~w, [~w|Ics], Line, Tlen, ~s, ~s) ->\n", [State,Char,Action,Alen]). out_head_max(File, State, Min, Action, Alen) -> io:fwrite(File, "yystate(~w, [C|Ics], Line, Tlen, ~s, ~s) when C >= ~w ->\n", [State,Action,Alen,Min]). out_head_range(File, State, Min, Max, Action, Alen) -> io:fwrite(File, "yystate(~w, [C|Ics], Line, Tlen, ~s, ~s) when C >= ~w, C =< ~w ->\n", [State,Action,Alen,Min,Max]). out_body(File, Next, Line, Action, Alen) -> io:fwrite(File, " yystate(~w, Ics, ~s, Tlen+1, ~s, ~s);\n", [Next,Line,Action,Alen]). %% pack_trans([{Crange,State}]) -> [{Crange,State}] when %% Crange = {Char,Char} | Char. %% Pack the translation table into something more suitable for %% generating code. We KNOW how the pattern matching compiler works %% so solitary characters are stored before ranges. We do this by %% prepending singletons to the front of the packed transitions and %% appending ranges to the back. This preserves the smallest to %% largest order of ranges. Newline characters, $\n, are always %% extracted and handled as singeltons. pack_trans(Trs) -> pack_trans(Trs, []). %% pack_trans(Trs) -> %% Trs1 = pack_trans(Trs, []), %% io:fwrite("tr:~p\n=> ~p\n", [Trs,Trs1]), %% Trs1. pack_trans([{{C,C},S}|Trs], Pt) -> % Singletons to the head pack_trans(Trs, [{C,S}|Pt]); %% Special detection and handling of $\n. pack_trans([{{Cf,$\n},S}|Trs], Pt) -> pack_trans([{{Cf,$\n-1},S}|Trs], [{$\n,S}|Pt]); pack_trans([{{$\n,Cl},S}|Trs], Pt) -> pack_trans([{{$\n+1,Cl},S}|Trs], [{$\n,S}|Pt]); pack_trans([{{Cf,Cl},S}|Trs], Pt) when Cf < $\n, Cl > $\n -> pack_trans([{{Cf,$\n-1},S},{{$\n+1,Cl},S}|Trs], [{$\n,S}|Pt]); %% Small ranges become singletons. pack_trans([{{Cf,Cl},S}|Trs], Pt) when Cl =:= Cf + 1 -> pack_trans(Trs, [{Cf,S},{Cl,S}|Pt]); pack_trans([Tr|Trs], Pt) -> % The default uninteresting case pack_trans(Trs, Pt ++ [Tr]); pack_trans([], Pt) -> Pt. %% out_actions(File, XrlFile, ActionList) -> ok. %% Write out the action table. out_actions(File, XrlFile, As) -> As1 = prep_out_actions(As), foreach(fun (A) -> out_action(File, A) end, As1), io:fwrite(File, "yyaction(_, _, _, _) -> error.~n", []), foreach(fun (A) -> out_action_code(File, XrlFile, A) end, As1). prep_out_actions(As) -> map(fun ({A,empty_action}) -> {A,empty_action}; ({A,Code,TokenChars,TokenLen,TokenLine}) -> Vs = [{TokenChars,"TokenChars"}, {TokenLen,"TokenLen"}, {TokenLine,"TokenLine"}, {TokenChars,"YYtcs"}, {TokenLen or TokenChars,"TokenLen"}], Vars = [if F -> S; true -> "_" end || {F,S} <- Vs], Name = list_to_atom(lists:concat([yyaction_,A])), [Chars,Len,Line,_,_] = Vars, Args = [V || V <- [Chars,Len,Line], V =/= "_"], ArgsChars = lists:join(", ", Args), {A,Code,Vars,Name,Args,ArgsChars} end, As). out_action(File, {A,empty_action}) -> io:fwrite(File, "yyaction(~w, _, _, _) -> skip_token;~n", [A]); out_action(File, {A,_Code,Vars,Name,_Args,ArgsChars}) -> [_,_,Line,Tcs,Len] = Vars, io:fwrite(File, "yyaction(~w, ~s, ~s, ~s) ->~n", [A,Len,Tcs,Line]), if Tcs =/= "_" -> io:fwrite(File, " TokenChars = yypre(YYtcs, TokenLen),~n", []); true -> ok end, io:fwrite(File, " ~s(~s);~n", [Name, ArgsChars]). out_action_code(_File, _XrlFile, {_A,empty_action}) -> ok; out_action_code(File, XrlFile, {_A,Code,_Vars,Name,Args,ArgsChars}) -> %% Should set the file to the .erl file, but instead assumes that %% ?LEEXINC is syntactically correct. io:fwrite(File, "\n-compile({inline,~w/~w}).\n", [Name, length(Args)]), L = erl_scan:line(hd(Code)), output_file_directive(File, XrlFile, L-2), io:fwrite(File, "~s(~s) ->~n", [Name, ArgsChars]), io:fwrite(File, " ~ts\n", [pp_tokens(Code, L, File)]). %% pp_tokens(Tokens, Line, File) -> [char()]. %% Prints the tokens keeping the line breaks of the original code. pp_tokens(Tokens, Line0, File) -> pp_tokens(Tokens, Line0, File, none). pp_tokens([], _Line0, _, _) -> []; pp_tokens([T | Ts], Line0, File, Prev) -> Line = erl_scan:line(T), [pp_sep(Line, Line0, Prev, T), pp_symbol(T, File) | pp_tokens(Ts, Line, File, T)]. pp_symbol({var,_,Var}, _) -> atom_to_list(Var); pp_symbol({_,_,Symbol}, File) -> format_symbol(Symbol, File); pp_symbol({dot, _}, _) -> "."; pp_symbol({Symbol, _}, _) -> atom_to_list(Symbol). pp_sep(Line, Line0, Prev, T) when Line > Line0 -> ["\n " | pp_sep(Line - 1, Line0, Prev, T)]; pp_sep(_, _, {'.',_}, _) -> ""; % No space after '.' (not a dot) pp_sep(_, _, {'#',_}, _) -> ""; % No space after '#' pp_sep(_, _, {'(',_}, _) -> ""; % No space after '(' pp_sep(_, _, {'[',_}, _) -> ""; % No space after '[' pp_sep(_, _, _, {'.',_}) -> ""; % No space before '.' pp_sep(_, _, _, {'#',_}) -> ""; % No space before '#' pp_sep(_, _, _, {',',_}) -> ""; % No space before ',' pp_sep(_, _, _, {')',_}) -> ""; % No space before ')' pp_sep(_, _, _, _) -> " ". %% out_dfa_graph(LeexState, DFA, DfaStart) -> ok | error. %% Writes the DFA to a .dot file in DOT-format which can be viewed %% with Graphviz. out_dfa_graph(St, DFA, DF) -> verbose_print(St, "Writing DFA to file ~ts, ", [St#leex.gfile]), case file:open(St#leex.gfile, [write]) of {ok,Gfile} -> try %% Set the same encoding as infile: set_encoding(St, Gfile), io:fwrite(Gfile, "digraph DFA {~n", []), out_dfa_states(Gfile, DFA, DF), out_dfa_edges(Gfile, DFA), io:fwrite(Gfile, "}~n", []), verbose_print(St, "ok~n", []), St after ok = file:close(Gfile) end; {error,Error} -> verbose_print(St, "error~n", []), add_error({none,leex,{file_error,Error}}, St) end. out_dfa_states(File, DFA, DF) -> foreach(fun (S) -> out_dfa_state(File, DF, S) end, DFA), io:fwrite(File, "~n", []). out_dfa_state(File, DF, #dfa_state{no=DF, accept={accept,_}}) -> io:fwrite(File, " ~b [shape=doublecircle color=green];~n", [DF]); out_dfa_state(File, DF, #dfa_state{no=DF, accept=noaccept}) -> io:fwrite(File, " ~b [shape=circle color=green];~n", [DF]); out_dfa_state(File, _, #dfa_state{no=S, accept={accept,_}}) -> io:fwrite(File, " ~b [shape=doublecircle];~n", [S]); out_dfa_state(File, _, #dfa_state{no=S, accept=noaccept}) -> io:fwrite(File, " ~b [shape=circle];~n", [S]). out_dfa_edges(File, DFA) -> foreach(fun (#dfa_state{no=S,trans=Trans}) -> Pt = pack_trans(Trans), Tdict = foldl(fun ({Cr,T}, D) -> orddict:append(T, Cr, D) end, orddict:new(), Pt), foreach(fun (T) -> Crs = orddict:fetch(T, Tdict), Edgelab = dfa_edgelabel(Crs, File), io:fwrite(File, " ~b -> ~b [label=\"~ts\"];~n", [S,T,Edgelab]) end, sort(orddict:fetch_keys(Tdict))) end, DFA). dfa_edgelabel([C], File) when is_integer(C) -> quote(C, File); dfa_edgelabel(Cranges, File) -> %% io:fwrite("el: ~p\n", [Cranges]), "[" ++ map(fun ({A,B}) -> [quote(A, File), "-", quote(B, File)]; (C) -> [quote(C, File)] end, Cranges) ++ "]". set_encoding(#leex{encoding = none}, File) -> ok = io:setopts(File, [{encoding, epp:default_encoding()}]); set_encoding(#leex{encoding = E}, File) -> ok = io:setopts(File, [{encoding, E}]). output_encoding_comment(_File, #leex{encoding = none}) -> ok; output_encoding_comment(File, #leex{encoding = Encoding}) -> io:fwrite(File, <<"%% ~s\n">>, [epp:encoding_to_string(Encoding)]). output_file_directive(File, Filename, Line) -> io:fwrite(File, <<"-file(~ts, ~w).\n">>, [format_filename(Filename, File), Line]). format_filename(Filename0, File) -> Filename = filename:flatten(Filename0), case enc(File) of unicode -> io_lib:write_string(Filename); latin1 -> io_lib:write_string_as_latin1(Filename) end. format_symbol(Symbol, File) -> Format = case enc(File) of latin1 -> "~p"; unicode -> "~tp" end, io_lib:fwrite(Format, [Symbol]). enc(File) -> case lists:keyfind(encoding, 1, io:getopts(File)) of false -> latin1; % should never happen {encoding, Enc} -> Enc end. quote($^, _File) -> "\\^"; quote($., _File) -> "\\."; quote($$, _File) -> "\\$"; quote($-, _File) -> "\\-"; quote($[, _File) -> "\\["; quote($], _File) -> "\\]"; quote($\s, _File) -> "\\\\s"; quote($\", _File) -> "\\\""; quote($\b, _File) -> "\\\\b"; quote($\f, _File) -> "\\\\f"; quote($\n, _File) -> "\\\\n"; quote($\r, _File) -> "\\\\r"; quote($\t, _File) -> "\\\\t"; quote($\e, _File) -> "\\\\e"; quote($\v, _File) -> "\\\\v"; quote($\d, _File) -> "\\\\d"; quote($\\, _File) -> "\\\\"; quote(C, File) when is_integer(C) -> %% Must remove the $ and get the \'s right. S = case enc(File) of unicode -> io_lib:write_char(C); latin1 -> io_lib:write_char_as_latin1(C) end, case S of [$$,$\\|Cs] -> "\\\\" ++ Cs; [$$|Cs] -> Cs end; quote(maxchar, _File) -> "MAXCHAR".