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Re: [Emacs-diffs] master 9d8d065: Add support for finalizers
From: |
Stefan Monnier |
Subject: |
Re: [Emacs-diffs] master 9d8d065: Add support for finalizers |
Date: |
Tue, 03 Mar 2015 13:18:10 -0500 |
User-agent: |
Gnus/5.13 (Gnus v5.13) Emacs/25.0.50 (gnu/linux) |
>> Question: why use a doubly-linked list, unlike pretty much everything
>> else in our code base?
> We remove finalizers from the middle of the list in unchain_finalizer.
> We could just rebuild the list as we scan it, but when we'd have to
> touch every node. Or we could maintain auxiliary state, but then in
> run_finalizers we'd have to scan the whole list instead of the part
> we're running.
You can remove them from the middle of the list with a singly-linked
list as well, by keeping a "double-indirection" pointer. That's what we
do for markers.
It's not ideal, but it's no worse than using doubly-linked lists.
>>> + DEFVAR_BOOL ("gc-precise-p", gc_precise_p,
>> This name is wrong. "-p" stands for "predicate" and a predicate is
>> a function that returns a boolean, whereas this is a variable/constant.
> I've also seen it for boolean-valued variables.
Oh, yes, you're not the only one introducing such horrors, but we should
still avoid making things worse in this respect.
Stefan