On 1/10/20 2:36 PM, Linas Vepstas wrote:
So, I've got lots of C code wrapped up in guile, and I'd like to declare many of these functions to be pure functions, side-effect-free, thus hopefully garnering some optimizations. Is this possible? How would I do it? A cursory google-search reveals no clues.To recap, I've got functions f and g that call into c++, but are pure (i.e. always return the same value for the same arguments). I've got user-written code that looks like this: (define (foo x) (g (f 42) (f x) (f 43)) and from what I can tell, `f` is getting called three times whenever the user calls `foo`. I could tell the user to re-write their code to cache, manually: viz: (define c42 (f 42)) (define c43 (f 43)) (define (foo x) (g c42 (f x) c43)) but asking the users to do this is .. cumbersome. And barely worth it: `f` takes under maybe 10 microseconds to run; so most simple-minded caching stunts don't pay off. But since `foo` is called millions/billions of times, I'm motivated to find something spiffy. Ideas? suggestions? -- Linas
read this: http://community.schemewiki.org/?memoization and look at https://docs.racket-lang.org/memoize/index.html
