add docs for using with-cache with TR #27
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It took me way too long to get with-cache working with TR, and the problem was doubly hard to find because of a bad error message. Specifically, if you import
*current-cache-keys*
with type(Any -> Any)
, then TR won't allowwith-cache
to call the procedures stored in the parameter. Should have been obvious, but the error message that's generated says something like "Internal error, can't serialize the key 14" or some such, which makes it sound like the problem is with the cached value, rather than with the key. In order to address this, I modified the error message but also added a section of documentation that shows a very simple example of using with-cache with Typed Racket.Hope this helps other people!