Defining tokens

Use Perl 6-like proto subs to define tokens

proto infix:<*> is looser('term:') { ... }
proto infix:</> is equiv(infix:<*>) { ... }

proto infix:<+> is looser(infix:<*>) { ... }
proto infix:<-> is equiv(infix:<+>) { ... }

proto circumfix:<( )> is equiv('term:') { ... }