[Haskell-cafe] Is StateT what I need?

[Judah Jacobson]

On Dec 17, 2007 1:04 PM, Brandon S. Allbery KF8NH <allbery at ece.cmu.edu> wrote:
>
> On Dec 17, 2007, at 15:41 , Brent Yorgey wrote:
>
> > Yes, and in fact, you don't even need foldM.  The only thing that
> > actually uses IO is the readFile, so ideally
>
> Actually, a quick check indicates that the regex functions used in
> getProcInfo are in IO as well (?!).
>

Those functions look pure to me:

GHCi, version 6.8.1: http://www.haskell.org/ghc/  :? for help
Loading package base ... linking ... done.
Prelude> :m +Text.Regex
Prelude Text.Regex> :t matchRegex . mkRegex
matchRegex . mkRegex :: String -> String -> Maybe [String]