grammar de.ugoe.cs.swe.bnftools.Ebnf hidden(WS, ML_COMMENT, SL_COMMENT)

import "http://www.eclipse.org/emf/2002/Ecore" as ecore

generate ebnf "http://www.ugoe.de/cs/swe/bnftools/Ebnf"

// -----------------------------------------------------------------------------------------------
// Parser Rules
// -----------------------------------------------------------------------------------------------
EtsiBnf:
	'grammar' name=ID
	(	type='/bnf'? ';' 
		(imports+=Import)* 
		(rule+=Rule | sectionheader+=SectionHeading)+ 
	)
	| 
	(	type='/delta' ';'
		(imports+=Import)* 
		(rule+=Rule | sectionheader+=SectionHeading | extRule+=ExtRule)*
	)
	| 
	(	type='/merge' ';' 
		(imports+=Import)* 
		(sectionheader+=SectionHeading | mergeRule+=MergeRule)* 
	)
;


SectionHeading:
	{SectionHeading}
	sectionHeader=SECTIONHEADER
;


Import :
 	'import' importURI=STRING 
 	('/' (grammarType='core' | grammarType='package' | grammarType='update'))?
 	('label:' label=ID)? ';'
;

Rule:
	(rulenumber=INT (rulevariant=ID)? '.')?  name=ID  '::=' (definitionList=DefinitionList)? ';'? 
;

ExtRule:
	(rulenumber=INT (rulevariant=ID)? '.')?  name=ID ('(' ruleext=INT ')') '<-' 
	(elements+=Atom | ')' | ']' | '}' | '|' | '(' | '[' | '{' | '*' | '+')* ';'? 
;

MergeRule:
	GlobalCombinator
	| RuleCombinator
	| HookCombinator
;
	
GlobalCombinator:
('global' 'combinator:') logic=LOGIC ';'?
;	

RuleCombinator:
('rule' 'combinator:' name=ID ) logic=LOGIC ('(' LABEL+=STRING ')')* ';'?
;

HookCombinator:
'hook' 'combinator:' name=ID '(' ruleext=INT ')' (logic=LOGIC)? ('(' LABEL+=STRING ')')+ ';'?
;

DefinitionList:
	singleDefinition+=SingleDefinition ('|' singleDefinition+=SingleDefinition)*
;

SingleDefinition:
	(terms+=Term)+
;

Term:
	termAtom=Atom
	| termGroupedSequence=GroupedSequence
	| termOptionalSequence=OptionalSequence
	| termRepeatedSequence=RepeatedSequence
;

Atom:
	atomStringRule=StringRule
	| atomRuleReference=RuleReference
;

RuleReference:
	ruleref=[Rule]
;

StringRule:
	literal=STRING
	| colon=COLON
;

GroupedSequence:
	'(' definitionList+=DefinitionList ')'
;

OptionalSequence:
	'[' definitionList+=DefinitionList ']'
;

RepeatedSequence:
	'{' definitions+=DefinitionList '}' morethanonce?='+'?
;

// -----------------------------------------------------------------------------------------------
// Lexer Rules
// -----------------------------------------------------------------------------------------------

terminal ID  		: ('a'..'z'|'A'..'Z'|'_') ('a'..'z'|'A'..'Z'|'0'..'9'|'_')* ;
terminal INT 		returns ecore::EInt: ('0'..'9')+;
terminal WS			: (' '|'\t'|'\r'? '\n')+;
terminal COLON		: '"' '"' '"';
terminal STRING		: '"' !('"')* '"' | "'" !("'")*"'";
terminal SECTIONHEADER: ('a'..'z'|'A'..'Z') ('.'|('0'..'9'))+ (' '|'\t') !('\n'|'\r')* '\r'? '\n';
terminal SL_COMMENT	: '//' !('\n'|'\r')* ('\r'? '\n')?;
terminal ML_COMMENT	: '/*' -> '*/';
//TODO: a more intuitive notation
terminal LOGIC		: '/and' | '/or' | '/andr' | '/orr' | '/any' | '/together' ;