Antlr: Simplest way to recognize dates and numbers?

number: (MONTH|INT);

date: month '/' day ( '/' year )? -> ^('DATE' year month day);

foo: STRING OP number -> ^(OP STRING number);
STRING: ('a'..'z')+;
OP: ('<'|'>');

INT: '0'..'9'+;

DATENUM: '0' '1'..'9';
INT: '0' | SIGN? '1'..'9' '0'..'9'*;

date: INT '/' INT ( '/' INT )?

date: (INT | DATENUM) '/' (INT | DATENUM) ('/' (INT | DATENUM) )?

date: month=INT '/' day=INT ( year='/' INT )? { year==null ? (/* First check /*) : (/* Second check */)}