pipelines

pipelines

[Marijn Schouten (hkBst)]

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Hi,

how would I construct a pipeline with guile? Currently my best attempt which
turns to nothing is:

guile> (use-modules (ice-9 popen))
guile> (with-output-to-port (open-pipe "echo" OPEN_WRITE) (lambda ()
(with-input-from-port (open-pipe* OPEN_READ "echo" "Hello world") (lambda ()
(display (readline))))))

Marijn

- --
Gods do not want you to think, lest they lose existence.
Religions do not want you to think, lest they lose power.

Marijn Schouten (hkBst), Gentoo Lisp project, Gentoo ML
<http://www.gentoo.org/proj/en/lisp/>, #gentoo-{lisp,ml} on FreeNode
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Re: pipelines

[Andy Wingo]

Hi Marijn,

On Sat 28 Mar 2009 05:53, "Marijn Schouten (hkBst)" <hkBst@gentoo.org> writes:

> how would I construct a pipeline with guile? Currently my best attempt which
> turns to nothing is:
>
> guile> (use-modules (ice-9 popen))
> guile> (with-output-to-port (open-pipe "echo" OPEN_WRITE) (lambda ()
> (with-input-from-port (open-pipe* OPEN_READ "echo" "Hello world") (lambda ()
> (display (readline))))))

What do you mean by "pipeline"? Do you want to spawn off "echo foo |
bar", or write data to "bar", or read data from "echo foo" ?

Andy
-- 
http://wingolog.org/

Re: pipelines

[Marijn Schouten (hkBst)]

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Andy Wingo wrote:
> Hi Marijn,
> 
> On Sat 28 Mar 2009 05:53, "Marijn Schouten (hkBst)" <hkBst@gentoo.org> writes:
> 
>> how would I construct a pipeline with guile? Currently my best attempt which
>> turns to nothing is:
>>
>> guile> (use-modules (ice-9 popen))
>> guile> (with-output-to-port (open-pipe "echo" OPEN_WRITE) (lambda ()
>> (with-input-from-port (open-pipe* OPEN_READ "echo" "Hello world") (lambda ()
>> (display (readline))))))
> 
> What do you mean by "pipeline"? Do you want to spawn off "echo foo |
> bar", or write data to "bar", or read data from "echo foo" ?
> 
> Andy

By pipeline I mean for example:

echo "Hello world" | cat | cat | cat | grep world | cat

I know how to create such pipelines that contain only a single pipe. My question
is about how to do it when there are many pipes.

Marijn

- --
Gods do not want you to think, lest they lose existence.
Religions do not want you to think, lest they lose power.

Marijn Schouten (hkBst), Gentoo Lisp project, Gentoo ML
<http://www.gentoo.org/proj/en/lisp/>, #gentoo-{lisp,ml} on FreeNode
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Re: pipelines

[Neil Jerram]

"Marijn Schouten (hkBst)" <hkBst@gentoo.org> writes:

> By pipeline I mean for example:
>
> echo "Hello world" | cat | cat | cat | grep world | cat
>
> I know how to create such pipelines that contain only a single pipe. My question
> is about how to do it when there are many pipes.

I don't know the answer myself, but can I suggest looking at what
guile-scsh does?  See http://arglist.com/guile.

    Neil

Re: pipelines

[Ludovic Courtès]

Hello!

"Marijn Schouten (hkBst)" <hkBst@gentoo.org> writes:

> how would I construct a pipeline with guile?

Here's an idea:

  (use-modules (ice-9 popen)
               (srfi srfi-1))

  (define (input-pipeline . args)
    (fold (lambda (program input)
            (with-input-from-port input
              (lambda ()
                (open-input-pipe program))))
          (current-input-port)
          args))

It can then be used like this:

  (read-line (input-pipeline "echo foo" "cat" "cat"
                             "grep foo" "sed -es/foo/bar/g"))
  => "bar"

Defining `output-pipeline' is left as an exercise to the reader.

Thanks,
Ludo'.