Re: Read multiple lines from an input-pipe

[Urs Liska]

Am 29.04.2014 13:26, schrieb Urs Liska:
> Am 29.04.2014 12:24, schrieb Urs Liska:
> > Hi all,
> >
> > I'm writing a set of functions to retrieve Git repository information
> > for use in a score:
> > https://github.com/openlilylib/snippets/tree/master/editorial-tools/git-commands
> >
> >
> >
> > I'm using a function provided by Lars Haulin in a comment to a blog post
> > that is essentially the one for open-input-pipe given here:
> > https://www.gnu.org/software/guile/manual/html_node/Pipes.html
> >
> > In addition to what is already there I want to write commands that use
> > more than one line of the Git commands' output (e.g. print the whole
> > commit message).
> > How would I approach that in Scheme?
> > What I need is for example a list of all strings that the command
> > outputs.
> > Do I have to write some kind of loop while the pipe is open?
> > Or is there a way to get the whole output as one string or a list of
> > strings?
>
> Well, RTFM at least gives a start:
> Using read-delimited instead of read-line returns the complete output in
> one string.
>
> And using (string-split git-function-name #\newline)
> provides me with a list of strings.
>
> Next step to find out will be to process this list of strings to a
> usable markup function ...
>
> Urs


I've tried around for quite some time now to no avail, probably having 
tried _everything_ except the right solution ;-) so I have to come back 
here and ask.

I now have this implementation:

#(use-modules (ice-9 popen))
#(use-modules (ice-9 rdelim))

#(define (strsystem_internal cmd)
   (let* ((port (open-input-pipe cmd))
          (str (read-delimited "" port)))
     (close-pipe port)
     str))

#(define-markup-command (gitCommand layout props cmd) (markup?)
   (let* ((result (string-split
                   (strsystem_internal (string-append "git " cmd))
                   #\newline)))
   (interpret-markup layout props
     (car result))))

If I feed it a command returning multiple lines, e.g.

\gitCommand "status"

this will create a markup with the first line of "git status"' result.

What way do I have to go to return either a \markuplist with all the 
lines or a number of \markups, one for each line?
If the command's result has only one line the function should only 
return a single \markup.
And it shouldn't hickup when the result is empty (i.e.. only an 
"eof-object?").

Thanks for any suggestions.
Urs