/* A.7 Regular Exrpessions */


pattern:
	disjunction
	;

disjunction:
	alternative
	| alternative PIPE disjunction
	;

alternative:
	/*
	 * SPEC:
	 * -empty-
	 *| alternative term
	 */
	(term)*
	;

term:
	assertion
	| atom
	| atom quantifier
	;

assertion:
	CAROT
	| DOLLAR
	| '\\b' /* double check this - looks like a space in the manual? */
	| '\\B' /* double check this - looks like a space in the manual? */
	;

quantifier:
	quantifierPrefix
	| quantifierPrefix QUESTION
	;

quantifierPrefix:
	ASTERISK
	| PLUS
	| QUESTION
	| LBRACE decimalDigits RBRACE
	| LBRACE decimalDigits COMMA RBRACE
	| LBRACE decimalDigits COMMA decimalDigits RBRACE
	;

atom:
	patternCharacter
	| DOT
	| BSLASH atomEscape
	| characterClass
	| LPAREN ((COLON|EQ|EXCLAMATION)? disjunction) RPAREN
	;

patternCharacter:
	sourceCharacter /* but not any of:
	^ $ \ . * + ? ( ) [ ] { } | 
		*/
	;

atomEscape:
	decimalEscape
	| characterEscape
	| characterClassEscape
	;

characterEscape:
	controlEscape
	| LOWER_C controlLetter
	| hexEscapeSequence
	| unicodeEscapeSequence
	| identityEscape
	;

controlEscape:
	CONTROL_ESCAPE_CHAR /* one of: fnrtv */
	;

controlLetter:
	/* one of: a-z A-Z */
	LOWER_ALPHA_CHAR
	| UPPER_ALPHA_CHAR
	;

identityEscape:
	sourceCharacter /* but not identifierPart */
	;

characterClassEscape:
	'd' | 'D' | 's' | 'S' | 'w' | 'W'
	;

decimalEscape:
	decimalIntegerLiteral /* lookahead not a member of decimalDigit */
	;

characterClass:
	/* [ [lookahead not a member of {^}] ClassRanges ] 
	| [ ^ classRanges ]
	*/
	;
	
classRanges:
	/* empty */
	| nonemptyClassRanges
	;

nonemptyClassRanges:
	classAtom
	| classAtom nonemptyClassRangesNoDash
	| classAtom MINUS classAtom classRanges
	;

nonemptyClassRangesNoDash:
	classAtom
	| classAtomNoDash nonemptyClassRangesNoDash
	| classAtomNoDash MINUS classAtom classRanges
	;

classAtom:
	MINUS
	| classAtomNoDash
	;

classAtomNoDash:
	sourceCharacter /* but not one of: \ ] - */
	| BSLASH classEscape
	;

classEscape:
	decimalEscape
	| LOWER_B
	| characterEscape
	| characterClassEscape
	;


LOWER_C	:	'c';



inputElementRegExp:
	lineTerminator
	| whiteSpace
	| comment
	| token
	| regularExpressionLiteral
	;
CONTROL_ESCAPE_CHAR
	:	'f'|'n'|'r'|'t'|'v'; /* one of: fnrtv */