[Python-Dev] test_popen broken on Win2K

Oren Tirosh oren-py-d@hishome.net
Mon, 10 Mar 2003 20:19:20 -0500

On Mon, Mar 10, 2003 at 11:52:39AM +1300, Greg Ewing wrote:
> > Those would be quite different functions, then, unless you proposed to have
> > Python interpret native shell metacharacters on its own too (e.g., set up
> > pipes, do the indicated file redirections, interpolate envars, and fake
> > whatever other shell gimmicks people may use).
> What we need is a function which does all those things,
> but uses some way of specifying them *other* than shell
> metacharacters. E.g.
>   os.plumb(("sed", "-e", "s/dead/resting/", "parrots"), 
>     ("grep", "norwegian"), output = myfile))

How about this:

cmd.sed('-e', 's/dead/resting', 'parrots') / cmd.grep('norwegian') >> myfile

or this:

def mygrep(pattern):

    def tran(upstream):
        for s in upstream:
             if re.search(pattern, s):
                 yield s

    return transformation(tran)

open('parrots') / (lambda s:s.replace('dead','resting')) / mygrep('norwegian')) >> open('myfile', 'w')

This is not some hypothetical syntax - I have a module that actually 
does this. It can mix python functions, generators and external commands 
in the same flow, use any iterable object as source, use a file, list 
or other data consumer as destination and a few more goodies.

It's not finished but it mostly works. I don't have much time to 
work on it, though.

oh-dear-what-have-I-done-now-I'll-have-to-finish-it-ly yours,