Monday, September 15, 2008

Scheme record syntax

I think if I were designing my own Scheme I'd tighten up some of the aspects of PLT's structs into a smaller syntactic footprint. In PLT, when you say
(define-struct thing (foo bar))
it binds thing to an identifier carrying static information about the struct type (which is needed for other macros such as match), struct:thing to a runtime value containing introspective information about the struct type, and make-thing to a constructor for the struct type.

I think I would just bind the single identifier thing for all three purposes: statically, it would carry the static information for match and friends; dynamically, it would be the constructor. (I never liked the imperative-sounding "make-" prefix.) For dynamic introspection, I would probably include a library form where you could say (struct foo) to reflect the struct type information into a dynamic value.

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