[Python-Dev] Re: Prospective Peephole Transformation

[Phillip J. Eby]

At 10:15 AM 2/18/05 -0500, Raymond Hettinger wrote:

>Only contains expressions are translated:
>
>     "if x in [1,2,3]"
>
>currently turns into:
>
>     "if x in (1,2,3)"
>
>and I'm proposing that it go one step further:
>
>     "if x in Seachset([1,2,3])"

ISTM that whenever I use a constant in-list like that, it's almost always 
with just a few (<4) items, so it doesn't seem worth the extra effort 
(especially disrupting the marshal module) just to squeeze out those extra 
two comparisons and replace them with a hashing operation.