[Haskell-cafe] Re: wanted: haskell one-liners (in the perl sense of one-liners)

Donald Bruce Stewart dons at cse.unsw.edu.au
Sun Mar 4 06:41:24 EST 2007


Yes, it definitely is a little lagged. It should be ported to use lazy
bytestrings too. I wsa more suggesting the one liners as examples of
haskell use in the shell.

tphyahoo:
> That seems like a really great thing to have. But I had troubles installing 
> it.
> 
> h4sh depends on hs-plugins.
> 
> And...
> ****************
> thartman at linodewhyou:~/haskellInstalls/hs-plugins$ ./Setup.lhs configure
> Setup.lhs: Warning: The field "hs-source-dir" is deprecated, please
> use hs-source-dirs.
> Configuring plugins-1.0...
> configure: /usr/local/bin/ghc-pkg
> configure: Dependency base-any: using base-2.0
> configure: Dependency Cabal-any: using Cabal-1.1.6
> Setup.lhs: cannot satisfy dependency haskell-src-any
> thartman at linodewhyou:~/haskellInstalls/hs-plugins$
> ****************
> Advice?
> 
> 2007/3/4, Donald Bruce Stewart <dons at cse.unsw.edu.au>:
> >There's some nice one liners bundled with h4sh:
> >
> >    http://www.cse.unsw.edu.au/~dons/h4sh.html
> >
> >For example:
> >
> >    http://www.cse.unsw.edu.au/~dons/h4sh.txt
> >
> >If you recall, h4sh is a set of unix wrappers to the list library.
> >I still use them everyday, though probably should put out a new release
> >soon.
> >
> >-- Don
> >
> >
> >tphyahoo:
> >> To answer my original question, here's a few ways to accomplish what I
> >> wanted with haskell
> >>
> >> Perl is still a lot faster than ghc -e, but I guess if you wanted
> >> speed you could compile first.
> >>
> >> ********************************************************************
> >>
> >> thartman at linodewhyou:~/learning/haskell/UnixTools$ ls -l
> >> total 16
> >> -rw-r--r-- 1 thartman thartman 2726 Dec 20 07:56 UnixTools.hs
> >> -rw-r--r-- 1 thartman thartman   82 Jan  7 07:18 echo.hs
> >> -rwxr--r-- 1 thartman thartman  790 Mar  4 05:02 oneliners.sh
> >> -rwxr--r-- 1 thartman thartman  646 Mar  4 04:18 oneliners.sh~
> >>
> >> thartman at linodewhyou:~/learning/haskell/UnixTools$ ./oneliners.sh
> >> haskell, ghc -e pipe
> >> 16
> >>
> >> real    0m1.652s
> >> user    0m0.600s
> >> sys     0m0.030s
> >> **********
> >> haskell, hmap pipe
> >> 16
> >>
> >> real    0m1.549s
> >> user    0m0.410s
> >> sys     0m0.200s
> >> **********
> >> haskell, two pipes
> >> 16
> >>
> >> real    0m2.153s
> >> user    0m0.900s
> >> sys     0m0.370s
> >> **********
> >> perl, two pipes
> >> 16
> >>
> >> real    0m0.185s
> >> user    0m0.010s
> >> sys     0m0.100s
> >>
> >> thartman at linodewhyou:~/learning/haskell/UnixTools$
> >>
> >>
> >> thartman at linodewhyou:~/learning/haskell/UnixTools$ cat oneliners.sh
> >> hmap (){ ghc -e "interact ($*)";  }
> >> hmapl (){ hmap  "unlines.($*).lines" ; }
> >> hmapw (){ hmapl "map (unwords.($*).words)" ; }
> >>
> >> function filesizes () {
> >>  find -maxdepth 1 -type f | xargs du
> >> }
> >>
> >> echo haskell, ghc -e pipe
> >> time filesizes | ghc -e 'interact $ (++"\n") . show . sum . map ( (
> >> read :: String -> Integer ) . head . words ) . lines '
> >> echo "**********"
> >>
> >> echo haskell, hmap pipe
> >> time filesizes | hmap '(++"\n") . show . sum . map ( ( read :: String
> >> -> Integer ) . head . words ) . lines'
> >> echo "**********"
> >>
> >> echo haskell, two pipes
> >> time filesizes | hmapl "map ( head . words )" | hmap '(++"\n") . show
> >> . sum . map ( read :: String -> Integer ) . lines'
> >> echo "**********"
> >>
> >> echo perl, two pipes
> >> time filesizes | perl -ane 'print "$F[0]\n"' | perl -e '$sum += $_
> >> while <>; print "$sum\n"'
> >>
> >>
> >> 2007/3/2, Thomas Hartman <tphyahoo at gmail.com>:
> >> >Okay, I am aware of
> >> >
> >> >http://haskell.org/haskellwiki/Simple_unix_tools
> >> >
> >> >which gives some implementation of simple unix utilities in haskell.
> >> >
> >> >But I couldn't figure out how to use them directly from the shell, and
> >> >of course that's what most readers will probably wnat.
> >> >
> >> >Or let me put it another way.
> >> >
> >> >Is there a way to do
> >> >
> >> >  find -maxdepth 1 -type f | xargs du | perl -ane 'print "\$F[0]\n"' |
> >> >perl -e '$sum += $_ while <>; print "$sum\n"'
> >> >
> >> >as a shell command that idiomatically uses haskell?
> >> >
> >> >For non-perlers, that sums up the disk usage of all files in the
> >> >current directory, skipping subdirs.
> >> >
> >> >print "\$F[0]\n
> >> >
> >> >looks at the first (space delimited) collumn of output.
> >> >
> >> >perl -e '$sum += $_ while <>; print "$sum\n"'
> >> >
> >> >, which is I guess the meat of the program, sums up all the numbers
> >> >spewed out of the first column, so in the end you get a total.
> >> >
> >> >So, anyone out there want to establish a haskell one liner tradition?
> >> >
> >> >:)
> >> >
> >> >thomas.
> >> >
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> >
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