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Re: cons* and append!

From: Stephen Compall
Subject: Re: cons* and append!
Date: 13 Feb 2004 15:58:18 -0600
User-agent: Gnus/5.09 (Gnus v5.9.0) Emacs/21.2

Brian S McQueen <address@hidden> writes:

> I few weeks back I asked abit about list building and I got some
> helpful responses.  The operator cons* was recommended to me.  Well
> I noticed append! yesterday.  Does anyone have any comments on this?
> It seems an excellent way of extending proper lists without copying
> or reallocating elements, since it merely clobbers the trailing null
> list of one list and inserts the car of the appended list in its
> place.  Are there some hidden expenses I am unaware of?  Does it
> have to walk the entire length of the first list to find the end?

Yes, it does.  This is why we have (ice-9 q) instead of just appending
new cells to the end.

Stephen Compall or s11 or sirian

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your control.  But your fear is yours, and yours alone, like your voice, or
your fingers, or your memory, and therefore yours to control.  If you feel
powerless over your fear, you have not yet admitted that it is yours, to do
with as you will.
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