[racket-dev] Blame and re-provided bindings

From: Robby Findler (robby at eecs.northwestern.edu)
Date: Sat Jan 15 12:29:12 EST 2011

On Sat, Jan 15, 2011 at 11:26 AM, Stevie Strickland
<sstrickl at ccs.neu.edu> 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.

I had imagined that the contract system would be able to pull out the
unwrapped value and apply the new contract to it (altho this wouldn't
work for the (listof (-> ...)) case, as Carl pointed out, unless we
made things more clever).

Alternatively, Redex should just move its contract off of the internal
file and on to the external one and we should just get on with our


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