'Token collision' in Boolean Query Parser

Answer 1

A token must be unique. You can, however, use the same token for several purposes in you syntax (like the unary and binary minus in Java).

I do not know the exact syntax of your environment, but something like changing the following two clauses

AND : ( 'AND' | '&' | 'EN' ) ;

and

andexpr : orexpr ((AND^ | PLUS^) orexpr)*;

would probably solve this issue.