Re: [stack] map fusion

On Fri, Aug 1, 2008 at 7:01 AM, William Tanksley, Jr
<[email protected]> wrote:
>> This seems to be yet another argument against n-ary combinators where
>> the quotation is not called a fixed number of times.
>
> _This_ I don't understand. What does that mean?
>
> I would have said "this is an argument against combinators which
> repeatedly call function inputs that do not have a statically known
> stack effect." Am I being too restrictive? Are you being too
> restrictive?

I agree with William. In a high level language, it'd generally be
better if the compiler can figure out its optimizations itself without
needing changes in the language design. Here, it should be easy to
check whether the quotation given affects values lower down on the
stack. In its fusion optimization, the compiler can just use this
information, rather than change the kind of program that the user
writes.

(Maybe map* would be good for documentation purposes or something, but
this is not a good justification for it.)

Dan