[plt-scheme] using syntax objects as hash table keys

From: Robby Findler (robby at cs.uchicago.edu)
Date: Sun May 16 17:45:05 EDT 2004

Did you see (lib "boundmap.ss" "syntax")?


On May 16, 2004, at 3:01 PM, Doug Orleans wrote:

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> I'd like to use syntax objects as keys in a hash table.  The problem
> is, I have no idea how to compute a hash code such that
> `module-identifier=?' identifiers map to the same code.  Anyone have
> any ideas?  I can't even use the symbol (i.e. `(syntax-e id)') as the
> key and have an alist for each symbol, since identifiers with
> different symbols might be `module-identifier=?' due to renaming.
> (Hm, can I just use `(cadr (identifier-binding id))' in that case?)
> --Doug
((lambda (x) (x x)) (lambda (x) (x x)))

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