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From:	"karl AT aspodata DOT se [via geda-user AT delorie DOT com]" <geda-user AT delorie DOT com>
To:	geda-user AT delorie DOT com
Subject:	readlink in guile (Re: [geda-user] system wide config)
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Comments:	In-reply-to "dmn (graahnul DOT grom AT gmail DOT com) [via geda-user AT delorie DOT com]" <geda-user AT delorie DOT com>
	message dated "Thu, 22 Apr 2021 09:16:32 +0300."
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Date:	Thu, 22 Apr 2021 14:33:23 +0200 (CEST)
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Dmitry:
> On Tue, 20 Apr 2021 16:46:34 +0200 (CEST)
> "karl AT aspodata DOT se [via geda-user AT delorie DOT com]" <geda-user AT delorie DOT com>
> wrote:
...
> > (define (readlink file)
> >   (let*
> >    (
> >     (port (open-input-pipe (string-append "readlink -f " file)))
> >     (str  (read-line port))
> >     (close-pipe port)
> >    )
> >    str
> >   )
> > )
...
> Karl, first of all, I'd like to thank you for not using the "dog's
> breakfast coding style" (TM)! :-)

What is that ?
Is it about all thoose {str|d}angling parentheses...

> Being not an expert in the bloody lisp programming language, I wonder
> does the call "(close-pipe port)" inside the "let" clause get executed?
> (It looks like a variable definition).

No, you are right, but I can do it like this (it is nice to have
open and close close to each other):

(define (readlink file)
  (let*
   (
    (port (open-input-pipe (string-append "readlink -f " file)))
    (str  (read-line port))
    (dummy (close-pipe port))
   )
   str
  )
)

but perhaps it is better doing this like:

(define (read1pipe cmd)
  (let*
   (
    (port (open-input-pipe cmd))
    (str  (read-line port))
   )
   (close-pipe port)
   str
  )
)

(define (readlink file) (read1pipe (string-append "readlink -f " file)))

Regards,
/Karl Hammar

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