The error message you're getting is literally correct - if not particularily
informative. Loading your program into (interactive) Hugs, I get:
[banner and loading info deleted]
Hugs session for:
/home/reid/share/hugs/lib/Prelude.hs
/home/reid/share/hugs/lib/System.hs
Ls.lhs
Type :? for help
Main> main
<<IO action>>
Notice that I can't execute Main.main because it doesn't have type "IO ()".
So now I add the type signature "main :: IO ()" and try again and things
work perfectly under both Hugs and runhugs.
Incidentally, there's no need to call your program "Ls.lhs" if you don't
want to. Adding +l to the end of the first line tells runhugs to assume
that the file is a literate script and you can rename the file to "ls"
if you like.
Alastair
> [EMAIL PROTECTED] reports the following problem.
>
> Version: Hugs 1.4 January 1998
> OS: x86 Linux
> compiler: gcc
> configuration:
> Expected behaviour:
> runhugs should execute "system" as interactive hugs does
> Observed behaviour:
> Some kind of internal error
>
> Transcript:
> $ ./Ls.lhs
> runhugs: lookupName: can't create Typeable instance
>
> Code:
> #!/usr/bin/runhugs
>
> > import System
>
> > main =
> > do
> > args <- getArgs
> > let args' = "ls":args
> > let s = unwords args'
> > status <- system s
> > exitWith status
>
>
>
