Joachim Breitner's Homepage

For all haskell-loving folks out they, consider these lines as an addon to your .bashrc:

    if which ghc >/dev/null

    then

	    function hmap { ghc -e "interact ($*)";  }

	    function hmapl { hmap  "unlines.($*).lines" ; }

	    function hmapw { hmapl "map (unwords.($*).words)" ; }

    fi	

This is somewhat an replacement to "perl -e", for cases where haskell does the job nicer. So, you like triangular text files? Then try

cat /etc/passwd | hmapl zipWith take [1..]

In most cases, you want to run hmapl with map or filter as the first argument, e.g.

cat /etc/passwd | hmapl map reverse

w|hmapl 'filter (List.isPrefixOf "j")' # essentially grep ^j

man ghc|hmapw 'filter (all Char.isAlpha)'