On Tue, Jul 17, 2012 at 11:34 PM, Richard O'Keefe
Here are two other possible reasons.
It's not just easier, stripPrefix pfx lst is *possible* as long as pfx is finite, even when lst is infinite. The same would not be true of a suffix stripper.
Isn't this the case with isSuffixOf, though? And yet it's there along with isPrefixOf...
It's so easy to write
stripSuffix sfx lst = case stripPrefix (reverse sfx) (reverse lst) of Nothing -> Nothing Just ys -> Just (reverse ys)
Sure, it's not difficult to write such a function; the issue is the asymmetry (and thus, broken user expectations) based on the rest of the library.
I can think of two cases where I'd want something like this. One is manipulating file extensions, where I'd want to use System.FilePath.splitExtension or something like that anyway. The other is suffix stripping for text processing, where I'd want to use a trie to match a whole lot of possible suffixes.
For what it's worth, there are a lot of other cases (outside of file path handling) in which I've found it useful.