On Sat, Jan 15, 2011 at 11:29 AM, Stevie Strickland <[email protected]> wrote: > On Jan 15, 2011, at 12:26 PM, Stevie Strickland wrote: >> On Jan 15, 2011, at 12:19 PM, Robby Findler wrote: >>> I think that we are just throwing up stumbling blocks. It is really a >>> design choice (does a reprovide "carry over" the contract or does it >>> put a new one on there?) and I seriously doubt there are any places >>> where someone does a reprovide intending to change the contract in >>> this manner. To the contrary, I expect that nearly every place where >>> someone does a reprovide, they indented to use the exact same contract >>> (with different parties now). >> >> This is possible, but _which_ parties? Do you wish to export internals >> through an external interface that should now take on the positive blame, so >> that you don't leak your internals (via module names and such used as blame >> parties)? This seems to me what you'd want for something like redex, but >> this requires more work, since you need to change the positive blame. This >> would require reapplying the contract projection to the original >> (pre-wrapped) value but different blame parties, which is more expensive and >> thus should be explicit, or some thought into how to engineer the contract >> system to make this possible without needing to reapply the projection. > > Actually, if this is only allowed before the value is used (i.e. on straight > reprovides of a contracted identifier), then we might be able to store some > syntax-time information and recreate the syntax transformer appropriately. > So perhaps it wouldn't be as expensive as I originally thought, though it > still seems that changing the positive blame information should be an > explicit operation, and I think it's really what you want here. I'll keep > thinking about this, though.
Oh, good point! That would solve both of Carl's objections, I believe. But I don't think we should think of it as 'changing the positive blame information' -- I agree anything phrased like that sounds wrong. Instead, I think we should be thinking "what is (provide f) shorthand for?". In the past I argued it was shorthand for "(provide/contract [f any/c])" but now I think that maybe we should be thinking of it as "(provide/contract [f <the-contract-f-was-imported-with-or-any/c-if-there-wasn't-one>])". Does that make more sense? Robby _________________________________________________ For list-related administrative tasks: http://lists.racket-lang.org/listinfo/dev
