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Re: "simplifications"
From: |
David Kastrup |
Subject: |
Re: "simplifications" |
Date: |
Mon, 19 Nov 2007 16:19:10 +0100 |
User-agent: |
Gnus/5.11 (Gnus v5.11) Emacs/23.0.50 (gnu/linux) |
Stefan Monnier <address@hidden> writes:
>> is not my idea of fun, or legible, or maintainable, or... you pick the
>> word. Not that c??r is much of an improvement; we should be able to
>> define accesor functions in the package
>
>> (defsubst ring--vec (ring)
>> (cdr (cdr ring)))
>
>> and have the byte-compiler optimize them away.
>
> 1 - if you use defsubst* the byte-code will look good.
> 2 - you can use defstruct to get all that and more.
> 3 - I don't think it's worth the trouble to make the byte-optimizer more
> complex for such little benefit. If you want to improve it, use the
> lexbind branch: it's a much saner starting point.
>
>
> Stefan "whose local Emacs hacks include some byte-optimizer
> improvement which does manage to optimize `cadr' but it's too
> much work works with too many limitations and on top of
> that, it's not even clear that the optimization is
> always correct: it doesn't account for the case where
> you do
> (defsubst cadr (debug-on-error) (car (cdr debug-on-error)))
> in which case the optimization is not semantics preserving"
defsubst is an advanced construct. I think it is reasonable to give
fewer guarantees about its operation than we do for defun.
--
David Kastrup
- "simplifications", David Kastrup, 2007/11/19
- Re: "simplifications", Juanma Barranquero, 2007/11/19
- Re: "simplifications", Stefan Monnier, 2007/11/19
- Re: "simplifications",
David Kastrup <=
- Re: "simplifications", Juanma Barranquero, 2007/11/19
- Re: "simplifications", Stefan Monnier, 2007/11/19
- Re: "simplifications", Juanma Barranquero, 2007/11/19
- Re: "simplifications", Stefan Monnier, 2007/11/19
- Re: "simplifications", Juanma Barranquero, 2007/11/19
- Re: "simplifications", Stefan Monnier, 2007/11/19
- Re: "simplifications", David Kastrup, 2007/11/19
- Re: "simplifications", Juanma Barranquero, 2007/11/19
- Re: "simplifications", Richard Stallman, 2007/11/19
- Re: "simplifications", Stefan Monnier, 2007/11/20