[antlr-interest] Left recursion problem

[HELLE Guillaume]

Hi!

I have a left recursion problem and i don't know how to solve it...
The problem is between "structure_controle" and "instruction"...
How i can solve it?
I am using antlr V3

Thanks for your advicean your help!

Best regards

Guillaume Helle


My grammar :

grammar lpr;

program : (commentaire|structure_controle|predicat_generation)* ;

predicat_generation
	:	'DEBUTBLOC(' site (',' site)* ')' instruction* 'FINBLOC';

site	:	'sit_' ('a'..'z'|'A'..'Z')+;

structure_controle
	:	'SI' condition 'ALORS' instruction ('SINON' instruction)*
'FINSI' |
		'TANTQUE' condition 'FAIRE' instruction 'FINFAIRE' |
		instruction |
		code_C;
		
commentaire
	:	'#' ( ~(newline) )* 
                 {_ttype = Token.SKIP;};
                 
code_C	:	'&' ( ~(newline) )*;

texte_libre
	:	(chaine_caractere*|' '|'\t')*;

condition
	:	'(' 
		(condition (('ET'|'OU') condition)* | 
		expression_arithmetique ('='|'<'|'>'|'<='|'>='|'<>')
expression_arithmetique)
		')';
	
instruction
	:	(
		condition |
		'REGLE' nom_regle |
		'APPEL' action_gascon |
		variable '=' expression_arithmetique |
		variable '=' expression_chaine |
		variable '=' condition |
		structure_controle
		) newline;		
	
expression_arithmetique
	:	'(' (
		terme_compose (('+'|'*'|'/'|'-') terme_compose)* |
		'-'* terme_compose |
		terme_compose '**' constante_entiere
		) ')';		

terme_compose
	:	expression_arithmetique | 
		'(' expression_arithmetique ')' |
		terme |
		'(' terme ')';
		
terme	:	(variable|constante|repere);

expression_chaine
	:	variable ('+' variable | chaine_caractere)* |
		chaine_caractere;

variable:	variable_locale | variable_globale;

variable_locale
	:	'lo' ('E'|'D'|'F'|'R'|'C'|'L'|'1'..'9' 'E'|'1'..'9' 'F')
chaine_caractere;
	
variable_globale
	:	'gl' ('a'..'z'|'A'..'Z')+ nom |
		'gl' nom |
		'GL' nom 'PANNE';
	
nom_regle
	:	nom;
		
action_gascon
	:	nom;
	
repere	:
('a'..'z'|'A'..'Z')('a'..'z'|'A'..'Z')('0'..'9')('0'..'9')('a'..'z'|'A'..'Z'
)+;	
			
nom	:	('a'..'z'|'A'..'Z'|'0'..'9')*;	

chaine_caractere:
	(nom|'_')*;
	
constante_entiere
	:	('+'|'-')* ('1'..'9')* ('0'..'9')+;
	
constante
	:	constante_entiere;
	
	
	
newline	:	'\r\n'|'\r'|'\n';
			
		
WS      : (' '|'\t'|'\n')+ {channel=99;}
;

;


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