Hi all,

I trying to match a dictionary of terms against free form input.  Many
of the dictionary entries have aliases, so I'm using a custom hash
table that matcheskeys by list membership.

My (maybe wrong) reading of the docs suggests that to match a hash
table, the table must be defined inline in the match clause.  This is
not really feasible because of the dictionary's size, so I am doing a
generic expression match instead: e.g., 

   ([list (? (lambda(e) (dict-ref mydict e #f)) pat)  _ ___]
      (let [(val (dict-ref mydict pat))]
         blah blah ))

This works ... but I have to do the lookup twice because match returns
the input pattern - i.e. the lookup key instead of the the resulting

Is there a way to avoid double lookup?  If necessary I can switch to a
normal (equal?) hash table by constructing the dictionary differently,
but I don't see that I will gain anything by doing so.


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