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> It occured to me that since the scheme execution process checks the
> number of arguments as it does the bindings of procedure arguments,
> it could (in theory) also check their types and thus allow type-based
> procedure call signatures like you get with java. Would this be at all
> useful? Would it make compilation of scheme code impossible? I guess
> it would be a pretty major extension to R4RS too.
>
> Well, just an idea...
I think Chez Scheme has an extension called case-lambda (or something
like that) where you can do pattern-matching on the number and
structure of the arguments:
(case-lambda
((a) ... code to run when called with one argument ...)
((a b) ... code to run when called with two arguments ...)
...)
I don't see any reason this couldn't be extended to:
(case-lambda
((a) ... blah ...)
((a b) ... blah ...)
((a (b c ...)) ... second argument must be a list of at least one
element, c is bound to its tail)
(((number? a) b c) ... three arguments, the first of which must be
a number ...))
Or something like that. Don't shoot me over the syntax.