wfs-operator-experiment/HMKNF.g4

grammar HMKNF;

WS: [ \n\t\r]+ -> skip;

kb: (lrule | orule)*;

lrule: ((head body) | head | body) '.';
head: IDENTIFIER (',' IDENTIFIER)*;
body: ':-' (katom (',' katom)*)?;

orule: oformula '.';
oformula:
	'(' oformula ')'								# parenth
	| oatom											# literal
	| oformula (operator = ('|' | '&')) oformula	# disjOrConj
	| oformula '->' oformula						# imp;

katom: patom | natom;
oatom: patom | fatom;
patom: IDENTIFIER;
natom: 'not' IDENTIFIER;
fatom: '-' IDENTIFIER;

IDENTIFIER: [a-z'][A-Za-z0-9']*;