On 21-Aug-1999, Heribert Schuetz <[EMAIL PROTECTED]> wrote:
> The appended patch to Hugs98 (to be applied in the src subdirectory)
> might be of some help for those who want to do shell scripting in
> Haskell. It modifies IO.openFile as follows:
>
> - If the name of a file opened in ReadMode ends in "|", then the part
> before the "|" is considered a program and its standard output is
> read.
>
> - If the name of a file opened in WriteMode begins with "|", then the
> part after the "|" is considered a program and it is written to its
> standard input.
>
> Several Unix programs have such a behaviour.
>
> With the patch applied, you can do things like this:
>
> do h <- openFile "cat /etc/group|" ReadMode
> h' <- openFile "|tr aeiou '*'" WriteMode
> hGetContents h >>= hPutStr h'
> hClose h
> hClose h'
This is a convenient hack, but IMHO it is not suitable for inclusion
in the Haskell standard library, because it increases the risk of
security holes in Haskell applications.
A better alternative would be to provide a new function named
"openFileOrPipe" with this augmented functionality.
--
Fergus Henderson <[EMAIL PROTECTED]> | "I have always known that the pursuit
WWW: <http://www.cs.mu.oz.au/~fjh> | of excellence is a lethal habit"
PGP: finger [EMAIL PROTECTED] | -- the last words of T. S. Garp.
