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

[Thomas Hartman]

with PCRE. now (and yep, it's a lot faster than posix):

***************************************************************************

thartman at linodewhyou:~/learning/haskell/UnixTools$ ./q-words.sh
q
qua
quack
quacked
quackery
quackery's
quacking
quacks
quad
quad's

real    0m6.691s
user    0m2.460s
sys     0m3.000s
q
qua
quack
quacked
quackery
quackery's
quacking
quacks
quad
quad's

real    0m1.032s
user    0m0.750s
sys     0m0.100s
thartman at linodewhyou:~/learning/haskell/UnixTools$ cat q-words.sh
time cat /usr/share/dict/american-english | ghc -e 'interact $
unlines. take 10 . filter ( \x -> x =~ "^q" :: Bool ) . lines'
ImportsRegexPosix.hs

time cat /usr/share/dict/american-english | ghc -e 'interact $
unlines. take 10 . filter ( \x -> x =~ "^q" :: Bool ) . lines'
ImportsRegexPCRE.hs

thartman at linodewhyou:~/learning/haskell/UnixTools$ cat ImportsRegexPosix.hs
import Text.Regex.Posix

thartman at linodewhyou:~/learning/haskell/UnixTools$ cat ImportsRegexPCRE.hs
import Text.Regex.PCRE

thartman at linodewhyou:~/learning/haskell/UnixTools$


2007/3/7, Thomas Hartman <tphyahoo at gmail.com>:
> In the spirit of making easy things easy, here is a "haskell from
> shell" one-line grepper, that uses regexen.
>
> Now, if only I could get pcre-regex installed I would be quite
> content. (Still stuck using posix RE for now.)
>
> **************
>
> thartman at linodewhyou:~/learning/haskell/UnixTools$ time ./q-words.sh
> q
> qua
> quack
> quacked
> quackery
> quackery's
> quacking
> quacks
> quad
> quad's
>
> real    0m3.186s
> user    0m1.900s
> sys     0m0.810s
>
> thartman at linodewhyou:~/learning/haskell/UnixTools$ cat q-words.sh
> cat /usr/share/dict/american-english | ghc -e 'interact $ unlines.
> take 10 . filter ( \x -> x =~ "^q" :: Bool ) . lines' Imports.hs
>
> thartman at linodewhyou:~/learning/haskell/UnixTools$ cat Imports.hs
> import Text.Regex.Posix
>
> ****************************
>
>
> 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.
> >
>