When I make a lookup in a "Binary Search Tree" to decide whether it is
equal to the root payload or it is in the left or right branch,
given the actual ord class definition, I have to make the comparison
twice: with "lt" and "le", or with the help of the eq class, "eq" and
then "lt".
while a "compare" function giving a ternary result {-1,0,1} or {LT, EQ,
GT} (haskell style) would cut the comparisons in half.
A possible solution would be to substitute in the constructor function
mkOrd, the second function "le" with a ternary result "compare"
function, and define "le" in terms of "compare".
_______________________________________________
Ur mailing list
[email protected]
http://www.impredicative.com/cgi-bin/mailman/listinfo/ur
