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Re: (list) and '(list)
From: |
Tim X |
Subject: |
Re: (list) and '(list) |
Date: |
Fri, 27 Apr 2007 10:58:34 +1000 |
User-agent: |
Gnus/5.11 (Gnus v5.11) Emacs/22.0.95 (gnu/linux) |
A Soare <alinsoar@voila.fr> writes:
> Can somebody tell me if there already is a code that makes the distintion
> between a list that evaluates as a function like
>
> (function ...
>
> and between a list that evaluates to itself :
>
> '(list ... , and its aliases like (quote (list ... etc
>
First, you have it around the wrong way. ' is the shorthand (alias if you like)
for (quote .....). If you ignore ', then a clear pattern emerges. Essentially,
all lists are evaluated when viewed from the top level. The (quote ....) is
different in that it short circuits evaluation - it returns its arguements
without evaluating them. In all other situations, the arguements are evaluated.
Putting it another way, given any list
(x y z)
x is always evaluated, but if x is the function quote, evaluation halts there.
otherwise, y and z are evaluated to determine the arguements to x.
I suspect you may be asking thw rong question. Maybe explain more about what
you want to do and others on the list will be able to give you better
advice/direction.
Tim
--
tcross (at) rapttech dot com dot au