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case-lambda* question

From: Daniel Llorens
Subject: case-lambda* question
Date: Mon, 12 Nov 2012 14:54:45 +0100

(define f
                ((a b c #:key x) 3)
                ((a #:key x) 1)))

scheme@(guile-user)> (g 0 #:x 1)
$1 = 3

The manual says

> Also, for completeness. Guile defines case-lambda* as well, which is like 
> case-lambda, except with lambda* clauses. A case-lambda* clause matches if 
> the arguments fill the required arguments, but are not too many for the 
> optional and/or rest arguments.
> Keyword arguments are possible with case-lambda*, but they do not contribute 
> to the “matching” behavior. That is to say, case-lambda* matches only on 
> required, optional, and rest arguments, and on the predicate; keyword 
> arguments may be present but do not contribute to the “success” of a match. 
> In fact a bad keyword argument list may cause an error to be raised.

I see that it gives 3 because ‘a b c’ matches ‘0 #:x 1’, so it's counting #:x 
as an ‘argument’ by itself. This is not what I expected from the description 
above. I think that the description should make clear that each item in the arg 
list is counted as an argument for the purposes of matching.

Moreover I think this behavior makes case-lambda* fairly useless, or even 
treacherous. I wonder what other people think.




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