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Re: Elisp development news
From: |
Marius Vollmer |
Subject: |
Re: Elisp development news |
Date: |
02 Jan 2002 22:50:42 +0100 |
User-agent: |
Gnus/5.09 (Gnus v5.9.0) Emacs/21.1 |
Neil Jerram <address@hidden> writes:
> You've now persuaded me that Jim's approach is functionally preferably
> to mine.
Ok, so let's go and implement Jim's approach. (That is, let's put it
on the TODO list... :-/ )
> [...]
>
> The concern is that I'm still worried about the performance impact of
> managing multiple false values and multiple end of list values. I
> know that Jim suggests a solution in his proposal, but am not
> convinced that it will not affect performance. What do you think
> about Jim's suggestion here, and do you have any other thoughts on
> implementation and performance?
It will affect performance, but I expect it to yield only a small
performance hit. I expect that, at worst, a test for falseness will
turn from a comparison with a constant to two comparisons with one
constant and one global variable.
> The question is whether the Elisp nil value should be distinct from
> the `nil' symbol. I presume yes (from your argument below) but just
> wanted to check. If yes, I further presume that the nil value should
> be a new SCM_MAKIFLAG value; is that right?
Yes, that what I thought so far. However, it might be better to make
nil a real symbol (i.e., satisfying our current SCM_SYMBOLP) and
somehow play tricks with the heap segments to still get a constant
value for the nil value (but I wouldn't know off-hand how to do this
portably).
- Re: Elisp development news,
Marius Vollmer <=