On 2012-06-25 20:17:33 -0600, Ryan Culpepper wrote: > IIUC from your later message, you've implemented the generics > analogue of object/c (per-instance contract), whereas > prop:dict/contract is closer to class/c (per-type contract). It's a > little fuzzy because prop:dict/contract hacks in per-instance > contracts too in a kind of ad hoc way.
That's a good point. The better analogy might be interface contracts vs. class/c. With generics, it is easy to control all points that an instance is created since constructors are just procedures. With classes, you can't get away with that since the instantiation forms are macros. The difference/advantage you might get with a per-type contract for generics is that you get a more interface-like blame story, as with interface contracts. Coverage isn't as much of an issue since you can just contract all constructors. Unfortunately, it's also not clear how to implement interface-like contracts for generics. Since the generics forms don't control the constructors, it's not obvious how to instantiate the blame at the construction site. Cheers, Asumu _________________________ Racket Developers list: http://lists.racket-lang.org/dev
