Andy Wingo <wi...@pobox.com> writes: > On Thu 05 May 2011 18:26, l...@gnu.org (Ludovic Courtès) writes: > >> Andy Wingo <wi...@pobox.com> writes: >> >>> If you call `map' or `for-each' with more than one list, our versions of >>> these operators will detect if the lists are of unequal length, and >>> throw an error in that case. >>> >>> However, SRFI-1 has long provided an extension to this, to allow for >>> early termination when any of the lists runs out. R6RS adopted this, >>> and it looks like R7RS will ratify that. >>> >>> So perhaps it's time for us to change as well. >> >> To change the default ‘map’ & ‘for-each’ to do like SRFI-1’s, right? > > Yeah, that was the proposal; but the argument is a bit weaker, now that > I found that the R6RS did not go with this change. So I don't really > know.
Oh, OK. > The reason I was thinking of doing this is because it turns out to help > performance to have map in scheme, at this point; or at least not hurt > it, and things will get better when we grow an optimizer. Yes, and I think we can keep rewriting SRFI-1 in Scheme, even in 2.0. > So I implemented map in Scheme, with circularity detection and all, only > to find strange errors in the ecmascript compiler (!). Turns out those > errors happened when loading goops, because it tried to extend a > primitive generic, but map wasn't a primitive any more, and instead of > failing nicely it corrupted memory. Ooh, interesting. :-) Thanks, Ludo’.
