Re: goops and memoization

[Carl R. Witty]

Mikael Djurfeldt <address@hidden> writes:

> That is an exciting idea.  It would be wonderful to be able to specify
> code re-writing rules such as:
> 
>   (map foo (map bar ls)) --> (map (lambda (x) (foo (bar x))))

The Haskell compiler GHC (http://www.haskell.org/ghc) has a mechanism
for specifying such rules; see
http://research.microsoft.com/Users/simonpj/Papers/rules.htm for a
paper on the topic.

Tom Lord points out that the above optimization does not always
preserve meaning; in general, I would expect many fewer valid
optimizations in Scheme than in Haskell (both because Scheme has side
effects, and because Scheme does not have a strong static type
system).

Carl Witty