Re: Treatment of unknown pragmas

Ben Gamari writes:

Brandon Allbery writes:

...

The problem with ANN is it's part of the plugins API, and as such does things like compiling the expression into the program in case a plugin generates code using its value, plus things like recompilation checking end up assuming plugins are in use and doing extra checking. Using it as a compile-time pragma is actually fairly weird from that standpoint.

True. That being said, I wonder if we solve most of these issues by simply type-checking ANNs lazily. That is, just forkM ANNs during typechecking. This would mean that the user wouldn't see an error if the expression contained inside is invalid. On the other hand, the cost of ANNs would decrease significantly and plugins which use them would continue to work unmodified. Strict typechecking behavior could be enabled via a flag.

I suppose the only issue with this idea is that we would also need to drop them from interface files, lest they would be forced. Perhaps this is sometimes reasonable, however.