I'm trying to improve the struct: form in TR, and one of the things I need to do is match a sequence of keyworded expressions, add annotations on the expressions, and then put them back into the same order.
I can either do a large ~or clause and have optional constraints on each clause, but If I do this then each kind of clause needs a different name and then putting them back in the same order is difficult. If I make a syntax class with each kind of clause then I don't know how to enforce the at most one constraint. Is there a way to do this with out duplicating the parsing work? Method 1: (~or (~optional guard:guard-form) (~optional mutable:mutable-form) property:struct-property-form) ... and #'(guard.contracted mutable.contracted property.contracted ...)) Method 2: (define-splicing-syntax-class any-form (pattern :guard-form) (pattern :mutable-form) (pattern :struct-property-form)) (form:any-form ...) and #'(form.contracted ...) ____________________ Racket Users list: http://lists.racket-lang.org/users
