Mark H Weaver <m...@netris.org> writes: > I can easily think of many possible uses for this, e.g. for memoizing > unary numeric functions, associating application-specific data > structures with file descriptors or array indices, etc. > > Regardless, our manual has been telling people they could do this for a > long time. To make matters worse, those who have tried using > object-properties have likely observed that it works as advertised. > They probably don't realize that it will silently fail for large > integers.
Fixing the documentation will not change the behavior. So they are not worse off than before. > 'eqv?' is Scheme's fundamental "operational equivalence" predicate. > 'eq?' is just an ugly efficiency hack, a poor cousin of 'eqv?' that > fails in surprising ways. No _correct_ program is ever broken by making > 'eq?' an alias to 'eqv?'. Many programs contain subtle bugs because of > their inappropriate use of 'eq?'. > > What's the argument on the other side? Is there a compelling reason to > use 'eq?' instead of 'eqv?' for object properties? object identity is checked by eq? and is conceptually different from value equality. When calling a thing an "object property", it is not helpful when it does not behave like one. -- David Kastrup
