Re: [Jscheme-user] Using apply with logical operators

[Ken A. <kan...@bb...>]

This is an interesting question.  I think that 
(apply and '(#t #t)) should be a syntax error, because and is considered syntax, and not a procedure.

In JScheme, and is an instance of Macro which is a subclass of Procedure.  Apply is a primitive that essentially calls .apply on its first argument and the list of remaining arguments.  For a Macro, .apply macroexpands the macro and arguments.

Scheme.analyze() calls .apply to get macroexpansion done, but for apply it should probably be and error.

The right way to apply a macro is like this:

(apply (lambda (a b) (and a b)) (list #t #f))

However, i did notice that (apply + 2 3) does not provide an informative error message, i'll fix that.

k


At 02:49 PM 4/5/2004 -0400, Borislav Iordanov wrote:
>Hi,
>
>I tried and-ing a list of boolean with:
>
>(apply and values)
>
>It doesn't work. Why is it possible to do:
>
>(apply + (list 2 2))
>
>But not:
>
>(apply and (list #t #t))?
>
>It seems like and is a macro that expands the above into:
>
>(if #t (and #t) #f)
>
>Of course, I can 'and' that list in many other ways, but just
>wondering....
>
>Thanks,
>Boris
>
>
>
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