Re: [Sbcl-devel] NREVERSE and REVERSE micro-optimization.

[Nikodemus S. <nik...@ra...>]

2009/9/2 Karol Swietlicki <mag...@gm...>:
> This is not that big of an improvement, but here goes.
>
> NREVERSE and REVERSE both perform run-time dispatch on type.
> Adding something like this:
>
> (deftransform reverse ((seq) (list))
>  `(sb-impl::list-reverse* seq))
> (deftransform nreverse ((seq) (list))
>  `(sb-impl::list-nreverse* seq))
> (deftransform reverse ((seq) (vector))
>  `(sb-impl::vector-reverse* seq))
> (deftransform nreverse ((seq) (vector))
>  `(sb-impl::vector-nreverse* seq))

A patch along these lines would not be unwelcome. There are also other
sequence functions which would benefit from similar attention, I
believe.

(Which is not to say this will not be done without someone sending in
a patch, but...)

Cheers,

 -- Nikodemus