Mark H Weaver <m...@netris.org> skribis: > l...@gnu.org (Ludovic Courtès) writes: > >> Mark H Weaver <m...@netris.org> skribis: >> >>> David Kastrup <d...@gnu.org> writes: >>> >>>> The manual states in "Object Properties": >>>> >>>> A single object property created by `make-object-property' can >>>> associate distinct property values with all Scheme values that are >>>> distinguishable by `eq?' (including, for example, integers). >>>> >>>> Integers are not documented to be reliably distinguishable by eq? (which >>>> means that equal integers might not be eq). >>> >>> Indeed, good point! >>> >>> I think we should change object-properties to use 'eqv?' hash operations >>> instead of 'eq?'. The only advantage to 'eq?' is a marginal efficiency >>> benefit, but that's no doubt lost in the noise, not only from the hash >>> table operations but from the use of fat mutexes. >>> >>> The only functional difference between Guile's 'eq?' and 'eqv?' is that >>> 'eq?' is not reliable on numbers. Our manual has been telling people >>> for years that integers can be used as keys for object properties. >>> Therefore, we should make it so. IMO, anyway. >>> >>> What do other people think? >> >> Associating object properties with numbers doesn’t seem useful to me, so >> my inclination would be to fix the manual, FWIW. > > 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.
[...] > What's the argument on the other side? Is there a compelling reason to > use 'eq?' instead of 'eqv?' for object properties? The argument would be the “ugly efficiency hack”. But I hear your argument, and I’m fine with changing this accordingly. Thanks, Ludo’.
