# PE Grammar for PE Grammars# # Adapted from [1] by Ian Piumarta <first-name at last-name point com>.# # Local modifications (marked '#ikp') to support:#     C text in '{ ... }' copied verbatim to output as 'semantic action'#     input consumed between '<' and '>' is 'char yytext[]' in semantic actions# # Best viewed using 140 columns monospaced with tabs every 8.# # [1] Bryan Ford.  "Parsing Expression Grammars: A Recognition-Based Syntactic#     Foundation."  Symposium on Principles of Programming Languages,#     January 14--16, 2004, Venice, Italy.# # Last edited: 2007-05-15 10:32:44 by piumarta on emilia # Hierarchical syntax Grammar		<- Spacing Definition+ EndOfFile Definition	<- Identifier 			{ if (push(beginRule(findRule(yytext)))->rule.expression) fprintf(stderr, "rule '%s' redefined\n", yytext); }		     LEFTARROW Expression	{ Node *e= pop();  Rule_setExpression(pop(), e); } &{ YYACCEPT }Expression	<- Sequence (SLASH Sequence	{ Node *f= pop();  push(Alternate_append(pop(), f)); }			    )*Sequence	<- Prefix (Prefix		{ Node *f= pop();  push(Sequence_append(pop(), f)); }	#ikp expanded from 'Seq <- Prefix*'			  )*		 / 				{ push(makePredicate("1")); }				#ikp addedPrefix		<- AND Action			{ push(makePredicate(yytext)); }	#ikp added		 / AND Suffix			{ push(makePeekFor(pop())); }		#ikp expanded from 'Prefix <- (AND/NOT)? Suffix'		 / NOT Suffix			{ push(makePeekNot(pop())); }		 /     SuffixSuffix		<- Primary (QUESTION		{ push(makeQuery(pop())); }			     / STAR		{ push(makeStar (pop())); }			     / PLUS		{ push(makePlus (pop())); }			   )?Primary		<- Identifier !LEFTARROW	{ push(makeName(findRule(yytext))); }		 / OPEN Expression CLOSE		 / Literal			{ push(makeString(yytext)); }		 / Class			{ push(makeClass(yytext)); }		 / DOT				{ push(makeDot()); }		 / Action			{ push(makeAction(yytext)); }		#ikp added		 / BEGIN			{ push(makePredicate("YY_BEGIN")); }	#ikp added		 / END				{ push(makePredicate("YY_END")); }	#ikp added # Lexical syntax Identifier	<- < IdentStart IdentCont* > Spacing		#ikp inserted < ... >IdentStart	<- [a-zA-Z_]IdentCont	<- IdentStart / [0-9]Literal		<- ['] < (!['] Char )* > ['] Spacing		#ikp inserted < ... >		 / ["] < (!["] Char )* > ["] Spacing		#ikp inserted < ... >Class		<- '[' < (!']' Range)* > ']' Spacing		#ikp inserted < ... >Range		<- Char '-' Char / CharChar		<- '\\' [abefnrtv'"\[\]\\]			#ikp added missing ANSI escapes: abefv		 / '\\' [0-3][0-7][0-7]		 / '\\' [0-7][0-7]?		 / '\\' '-'					#ikp added		 / !'\\' .LEFTARROW	<- '<-' SpacingSLASH		<- '/' SpacingAND		<- '&' SpacingNOT		<- '!' SpacingQUESTION	<- '?' SpacingSTAR		<- '*' SpacingPLUS		<- '+' SpacingOPEN		<- '(' SpacingCLOSE		<- ')' SpacingDOT		<- '.' SpacingSpacing		<- (Space / Comment)*Comment		<- '#' (!EndOfLine .)* EndOfLineSpace		<- ' ' / '\t' / EndOfLineEndOfLine	<- '\r\n' / '\n' / '\r'EndOfFile	<- !. Action		<- '{' < [^}]* > '}' Spacing		#ikp addedBEGIN		<- '<' Spacing				#ikp addedEND		<- '>' Spacing				#ikp added