Now, where "isEmpty" is replaced by "null", I'ld rather see "subset" instead of "isSubsetOf", particularly also because
"isProperSubsetOf" is so long.
I vote for consistently using isXXXX for predicates.
Maybe I should remind the main guideline I used for naming: follow the naming scheme of "Data.List" as close as possible, for maximal consistency inside hierarchical libraries. This justifies "isSubsetOf" (modelled after "isPrefixOf"), and "null". I notice that "null" is not classified as a predicate in Data.List documentation. "isEmpty" can always be added, but then, it would be logical to add such a function for lists too. Cheers, JP. __________________________________ Do you Yahoo!? Yahoo! Mail - More reliable, more storage, less spam http://mail.yahoo.com