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Re: Dotted pair call argument

From: David Kastrup
Subject: Re: Dotted pair call argument
Date: Tue, 21 Feb 2012 16:59:18 +0100
User-agent: Gnus/5.13 (Gnus v5.13) Emacs/24.0.92 (gnu/linux)

Mark H Weaver <address@hidden> writes:

> David Kastrup <address@hidden> writes:
>> I guess my "real" problem is that I'd like to do call wrapping by writing
>> (lambda ( . x) (fun . x))
>> instead of having to write
>> (lambda ( . x) (apply fun x))
>> I assume eval is not supposed to try dealing with dotted lists?
> The problem is that (f . (g x y)) is equivalent to (f g x y).
> Therefore, while Scheme could in theory support procedure calls with a
> dotted tail that happened to be an atom, it would do something rather
> different and confusing if the dotted tail was itself a procedure/macro
> call.

A list in dotted tail position is evaluated via (map ... eval) rather
than (eval ...).  I don't see much of a problem with that.

It works fine for () as one can see:
guile> (+ . ())

So why not for others?

David Kastrup

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