Attempt to define Mercury grammar

mercury_alt.g

grammar mercury_alt;

//options {
// backtrack = true;
// memoize=true;
//}

model:
    s item*;
    
//http://www.mercury.csse.unimelb.edu.au/information/doc-release/mercury_ref/Terms.html#Terms
item: term TERM_END s;

term
	:	 (altFunctor);

listTerm
	:	OPEN_LIST s commaSeparatedFunctors CLOSE_LIST;
	
tupleTerm
	:	OPEN_CURLY s commaSeparatedFunctors CLOSE_CURLY;
	
s	:	 (SL_COMMENT | ML_COMMENT | WS | LINE)*;

commaSeparatedFunctors
	:	 (functor (COMMA s functor)*)?;

altFunctor
	:	 ('?-' s| ':-' s)? altPrec1200;

altPrec1200
	:	altPrec1199 ((':-' s| '-->' s) altPrec1199)?
	;

altPrec1199
	: (('end_module'//                      fx                1199
	|'import_module'//                   fx                1199
	|'include_module'//                  fx                1199
	|'initialise'//                      fx                1199
	|'initialize'//			fx		  1199
	|'finalise'//			fx		  1199
	|'finalize'//			fx		  1199
	|'inst'//                            fx                1199
	|'instance'//                        fx                1199
	|'mode'//                            fx                1199
	|'module'//                          fx                1199
	|'pragma'//                          fx                1199
	|'promise'//                         fx                1199
	|'rule'//                            fx                1199
	|'typeclass'//                       fx                1199
	|'use_module'//                      fx                1199
) s)? altPrec1181;

altPrec1181
	:	('solver' s altPrec1181) | altPrec1180;

altPrec1180
	:	('type' s altPrec1180) | altPrec1179;

altPrec1179
	:	 altPrec1175 ('--->' s altPrec1179)?;
	
altPrec1175
	:	 altPrec1170
	 (('::' |'==>' | 'where') s altPrec1170)?;
	 
altPrec1170
	:	altPrec1160 ('else' altPrec1170)? ;

altPrec1160
	:	 ('if' s)? altPrec1150;

altPrec1150
	:	 altPrec1100 ('then' s altPrec1100)?;
	
altPrec1100
	:	 altPrec1050 (';' s altPrec1100)?;
	
altPrec1050
	:	 altPrec1025 ('->' s altPrec1050)?;

altPrec1025
	:	altPrec1000 ('&' s altPrec1025)?;

altPrec1000
	:	 prec950 (COMMA s altPrec1000)?;


functor
	: ('?-' s| ':-' s)? prec1200;
	
prec1200
	:	prec1199 ((':-' s| '-->' s) prec1199)?
	;

prec1199
	: (('end_module'//                      fx                1199
	|'import_module'//                   fx                1199
	|'include_module'//                  fx                1199
	|'initialise'//                      fx                1199
	|'initialize'//			fx		  1199
	|'finalise'//			fx		  1199
	|'finalize'//			fx		  1199
	|'inst'//                            fx                1199
	|'instance'//                        fx                1199
	|'mode'//                            fx                1199
	|'module'//                          fx                1199
	|'pragma'//                          fx                1199
	|'promise'//                         fx                1199
	|'rule'//                            fx                1199
	|'typeclass'//                       fx                1199
	|'use_module'//                      fx                1199
) s)? prec1181;

prec1181
	:	('solver' s prec1181) | prec1180;

prec1180
	:	('type' s prec1180) | prec1179;

prec1179
	:	 prec1175 ('--->' s prec1179)?;
	
prec1175
	:	 prec1170
	 (('::' |'==>' | 'where') s prec1170)?;
	 
prec1170
	:	prec1160 ('else' prec1170)? ;

prec1160
	:	 ('if' s)? prec1150;

prec1150
	:	 prec1100 ('then' s prec1100)?;
	
prec1100
	:	 prec1050 (';' s prec1100)?;
	
prec1050
	:	 prec1025 ('->' s prec1050)?;

prec1025
	:	prec1000 ('&' s prec1025)?;

prec1000
	:	 prec950 /*(',' s prec1000)?*/;

prec950
	://TODO, how to make it work? It fails because the ambiguite between the prefix + and the infix + in these positions.
//		((('all' | 'arbitrary' | 'promise_equivalent_solutions' | 'promise_equivalent_solution_sets' | 'require_complete_switch' | 'some' ) s) prec920 s prec950) | 
	((('promise_impure' | 'promise_pure' | 'promise_semipure' | 'require_det' | 'require_semidet' | 'require_multi' | 'require_cc_multi' | 'require_cc_nondet' | 'require_erroneous' | 'require_failure') s) prec920) |
	((('promise_exclusive' | 'promise_exclusive_exhaustive' | 'promise_exhaustive') s) prec950) |
	prec920;

prec920
	:	prec900 (('<=' | '<=>' | '=>') s prec920)?;

prec900
	: ((('\\\\+' | 'not' | '~') s) prec900) |
	(prec800 ('when' s prec800)?);

prec800
	: ((('impure' | 'semipure') s) prec800)  |
  prec740 |
	(('func' | 'pred') s prec740);

prec740
 	:	 prec720 ('or' s prec740)?;

prec720
 	:	 prec701 ('and' s prec720)?;

prec701
 	:	 prec700 ('is' s prec700)?;
 	
prec700
	:	 prec650 (('<' | '=' | '=..' | '=:=' | '=<' | '==' | '=\\\\=' | '>' | '>=' | '@<' | '@=<' | '@>' | '@>=' | '\\\\=' | '\\\\==' | '~=') s prec650)?;
	
prec650
	:  prec550 ((':=' | '=^') s prec550)?
	;


prec550
	:	prec500 ('..' s prec500)?;
	
prec500
	: ('+' s prec400 /*why not fy? */) |
//	  (prec400 (('+' s prec400)* | ('++' s prec400)? | ('-' s prec400)* | ('--' s prec400)* | ('/\\\\' s prec400)* | ('\\\\/' s prec400)*));
	  (prec400 (('+' s prec400)+ | ('++' s prec400) | ('-' s prec400)+ | ('--' s prec400)+ | ('/\\\\' s prec400)+ | ('\\\\/' s prec400)+)?);

prec400
//	:	 prec200 (('*' s prec200)* | ('/' s prec200)* | ('//' s prec200)* | ('<<' s prec200)* | ('>>' s prec200)* | ('div' s prec200)* | ('mod' s prec200)? | ('rem' s prec200)?);
	:	 prec200 (('*' s prec200)+ | ('/' s prec200)+ | ('//' s prec200)+ | ('<<' s prec200)+ | ('>>' s prec200)+ | ('div' s prec200)+ | ('mod' s prec200) | ('rem' s prec200))?;
	
prec200
	:	(('-' | '\\\\') s)? prec120 ('**' prec120)?;
	
prec120
	:	prec100 ((':' | ('`' (NAME ((END NAME)*)|VARIABLE) '`')) s prec100)*;
	
prec100
	:	('^' s)? prec99;
	
prec99
	:	prec90 ('^' s prec99)?;
	
prec90
	:	prec40 ('@' s prec40)?;

prec40
	:	(('!' | '!.' | '!:') s)? prec10;

prec10
	:	prec0 ((END ~(WS | SL_COMMENT | ML_COMMENT | EOF))=>'.' prec0)*;

prec0
	:	 (NAME | FLOAT | STRING | parenthezedTerm | listTerm | tupleTerm | VARIABLE) (OPEN_CT s commaSeparatedFunctors CLOSE)? s;

parenthezedTerm: OPEN_CT term CLOSE;


//lexer grammar mercury;

//http://www.mercury.csse.unimelb.edu.au/information/doc-release/mercury_ref/Tokens.html#Tokens
fragment DIGIT: '0'..'9';

////TODO handle ints, 0b, 0o, 0x, 0'
FLOAT : (DIGIT+ ('.' DIGIT+)? |('.' DIGIT+)) ('E'|'e'('+'|'-')?DIGIT+)?; 


LINE:
    '#' /*INT*/DIGIT+ '\n'
;

STRING:
    ('"' ( '\\' ('a'|'b'|'t'|'n'|'f'|'r'|'u'|'"'|/*'\''|*/'\\') | ~('"' | '\\') )* '"')+
;

NAME:
    (('a'..'z') ('a'..'z'|'A'..'Z'|'_'|'0'..'9')*)/* |
    ('\'' ( '\\' ('a'|'b'|'t'|'n'|'f'|'r'|'u'|'"'|'''|'\\') | ~('\'' | '\\') )* '\'')+*/
	;

VARIABLE:
    ('A'..'Z'|'_') ('a'..'z'|'A'..'Z'|'_'|'0'..'9')*
;

IMPLEMENTATION_DEFINED_LITERAL:
    '$' (('a'..'z') ('a'..'z'|'A'..'Z'|'_'|'0'..'9')*)
;

OPEN_CT:
    '('
;

CLOSE: ')';

OPEN_LIST:'[';
CLOSE_LIST
	:	']';

OPEN_CURLY:'{';
CLOSE_CURLY:'}';

HEAD_TAIL_SEPARATOR:'|';

COMMA:',';

END:'.';

WS         : (' '|'\t'|'\r'|'\n')+;

SL_COMMENT 
	:	 ('%' (~ '\n')*);
	
ML_COMMENT
	:	 '/*' (options {greedy=false;} : .)* '*/' /*{$channel=HIDDEN;}*/;

TERM_END
	:	'.' (WS | SL_COMMENT | ML_COMMENT | EOF);

The https://gist.github.com/3025801/d6ca0081f11807618cc1128e40af39aa2234ad3a version seems to be working (except the precedent rule 950, and the comma in precedent rule 1000) for the simplest Hello World (without the syntactic sugar of !, and still requires backtracking because of the . handling), but it fails for the imput like:

main(!IO) :-
io.write_string("Hello, ", !IO),
io.write_string("World!", !IO),
io.nl(!IO).

The https://gist.github.com/3025801/2b48f39914721191f0f3cad9ad2c2520a62bfbf5 version uses an alternative path to handle the different , usages, better . handling. Although the precedence rule 950 still not working well.