Re: [Haskell-beginners] Re: ghci access to .hs functions

On Thu, Aug 12, 2010 at 01:42:58AM -0700, prad wrote:

On Thu, 12 Aug 2010 09:01:42 +0100 Brent Yorgey wrote:

...

Can you show us the exact contents of your .hs file? certainly! but now i take it all back! :( it's working fine without the return().

it compiles main when i :l or when i ghci the file from the command line.

so now i think i'm delusional. :D :D

anyway, here's some of the code below and i'll ask another question. in the function:

-- edFil: edits a file with vim -- edFil :: String -> IO GHC.IO.Exception.ExitCode (not in scope error) edFil kV = rawSystem "vim" ["+source ~/.vim/ftplugin/html/HTML.vim",kV]

i got the type from ghci, but if i actually put it in i get error: Not in scope: type constructor or class `GHC.IO.Exception.ExitCode'

In order to be able to refer to a type you must import a module which exports it. However you are free to *use* a type without importing it, as long as you do not actually refer to it in a type signature. This is why your code works without the type signature. Just add import GHC.IO.Exception and then you will be able to give the type signature edFil :: String -> ExitCode -Brent