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. Stevie _________________________________________________ For list-related administrative tasks: http://lists.racket-lang.org/listinfo/dev
