Re: io.popen read and write, again

[Sean Conner <sean@...>]

It was thus said that the Great Jay Carlson once stated:
> On Feb 26, 2014 10:09 PM, "Sean Conner" <sean@conman.org> wrote:
> >
> > It was thus said that the Great Gary V. Vaughan once stated:
> > >
> > > Interestingly, the first version of this used luaposix to hook up the
> > > pipes, which required a lot more code and was considerable more hairy.
> > > But most of the overhead is in setting up the pipes, so for no noticeable
> > > speedup in execution and swapping a dependency on /bin/sh for a dependency
> > > on luaposix, I got to maintain all the low-level grungy pipe hookups
> > > instead of letting /bin/sh do the work.
> >
> >   Actually, there is some stuff you can do.  Like LPeg, you can create Unix
> > command objects [1] such that you could do:
> >
> >         list = {}
> >         cmd = U("ls -l") .. U("grep foobar") / "grep-stderr" .. function()
> >                         for line in io.lines() do
> 
> For maximum fun, use a non-blocking io implementation. You can have
> arbitrary lua tasklets at any stage of the pipeline, I think.

  Well, that was all theory, seeing how nobody has actually *implemented*
what I outlined.  

  But allowing arbitrary Lua coroutines (is that what you mean by
"tasklet"?) will be challenging to get right.  


> >                           table.insert(list,line)
> >                         end
> >                   return 0
> >                 end
> >         result = R(cmd) -- actually run the command
> 
> Doesn't anybody call methods anymore?

  Oh, you mean 

	result = cmd()

  -spc