I'm working on a little toy program in hbc (now that I have a haskell
compiler running I decided to give it a try ;), but I seem to have run into
a monad problem. Here's the snippet in particular (and the results from
evaluation in hbi):
> getDirectoryContents "." >>= filter (\(x:_) -> x /= '.');
[65] Cannot unify types:
Prelude.IO
and (Prelude.[])
in (>>=) (getDirectoryContents ".") (filter (\I ->
case I of {
Prelude.[] -> Pfail "No match in Pinteractive"
| (:) x I4625 -> (/=) x '.'
}
))
(The idea here is to filter out all the dot files from the directory
listing)
Unfortunately I can't make hide or hair of this. Is this because the
function being used with filter would break when given an empty list (or is
that Pfail bit there to handle that breaking?)
TIA
--
-Simon Raahauge DeSantis
