> Although I have tried to make sense what lexicographic order means I haven't > figured out. Maybe an example with a simple application of this would be > helpful. To be honest I can't understand what the symbol <= really means.
<= means "less than or equal to". Normally, lexicograpic order is the order in which words would appear in a lexicon. This can be generalized to other data types than strings by the kind of comparison done here, by specifying an ordering of the constructors (in this case Leaf < Branch). Cheers, /Niklas _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe