The programs run under Hugs 98 as of September 1999 or February 2001
(or GHC 4.04 or GHC 4.08). Since the code uses rank-2 type signatures
Hugs must be called setting the flag
-98, for instance,
hugs -98 Main.lhs (for GHC add
-fglasgow-exts to the command line
arguments). NB. Since some of the trie types have
second-order kinds, Haskell's
Show class cannot be used
to print elements of these types. Instead, we have to code the
printing routines by hand (employing the technique of polytypic
programming once again).
Term Int(including example calls).