getting output from external process in a variable

getting output from external process in a variable

[Daan Hoogland]

H all,

I'm doing some application programming in elisp. I read /etc/group with 
grep and edit the temporary buffer with results. now I end up with 
groupname:member1,member2 and I want it in a list:
(list "groupname" (list "member1" "member2"))
now I can edit the buffer to cantain the lisp expression and then 
evaluate it like:
(set 'var (list "groupname" (list "member1" "member2")))
and use var. But I was wondering wether there was somewhere maybe an 
api that can set a var to a region in the current buffer directly.

Am I understanding emacs and lisp here?
Is there maybe a better/quicker solution?

Is there such a function that could for instance read-list-from-text 
from start to end with delimiters?
Or one that can just take text and put it in a variable?

Any comment appreciated.

D.A.A.N.

Re: getting output from external process in a variable

[Gareth Rees]

Daan Hoogland wrote:
> I end up with [a buffer containing lines of the form]
> groupname:member1,member2 and I want it in a list:
> (list "groupname" (list "member1" "member2"))

  (require 'cl)
  (defun munge-buffer ()
    (goto-char (point-min))
    (loop while (re-search-forward "^\\(\\w+\\):\\(\\w+\\),\\(\\w+\\)$" nil t)
          collect `(,(match-string 1) (,(match-string 2) ,(match-string 3)))))

-- 
Gareth Rees

Re: getting output from external process in a variable

[Stefan Monnier]

>>>>> "Daan" == Daan Hoogland <emacs@onecht.net> writes:
> groupname:member1,member2 and I want it in a list:
> (list "groupname" (list "member1" "member2"))

  (when (re-search-forward ":\\([^,]*\\)," nil t)
    (list (buffer-substring (point-min) (match-beginning 0))
          (list (match-string 1)
                (buffer-substring (point) (point-max)))))

I don't recommend the above style (especially using (point) instead of
(match-end 0)), but that should get you started.


        Stefan

Re: getting output from external process in a variable

[Kevin Rodgers]

Daan Hoogland wrote:

> H all,
> 
> I'm doing some application programming in elisp. I read /etc/group with 
> grep and edit the temporary buffer with results. now I end up with 
> groupname:member1,member2 and I want it in a list:
> (list "groupname" (list "member1" "member2"))
> now I can edit the buffer to cantain the lisp expression and then 
> evaluate it like:
> (set 'var (list "groupname" (list "member1" "member2")))
> and use var. But I was wondering wether there was somewhere maybe an api 
> that can set a var to a region in the current buffer directly.


C-h v buffer-string
C-h v buffer-substring


> Am I understanding emacs and lisp here?
> Is there maybe a better/quicker solution?

I think so:

(let ((group-members (split-string (buffer-string) ":")))
   (list (car group-members) (split-string (cadr group-members) ",")))

-- 
Kevin Rodgers

Re: getting output from external process in a variable

[Kai Grossjohann]

Daan Hoogland <emacs@onecht.net> writes:

> I'm doing some application programming in elisp. I read /etc/group
> with grep and edit the temporary buffer with results. now I end up
> with groupname:member1,member2 and I want it in a list:
> (list "groupname" (list "member1" "member2"))
> now I can edit the buffer to cantain the lisp expression and then
> evaluate it like:
> (set 'var (list "groupname" (list "member1" "member2")))
> and use var. But I was wondering wether there was somewhere maybe an
> api that can set a var to a region in the current buffer directly.

I don't know what it means to "set a var to a region in the current
buffer directly".  Maybe you mean that you want a variable that
contains a string which is a part of the current buffer?  See the
buffer-substring and buffer-substring-no-properties functions.

Maybe you mean that you want to have ("groupname" ("member1"
"member2")) in the buffer and then "directly", in some manner,
transfer this list into a Lisp variable.  In that case, investigate
the function read.  Basically, you put point in front of the open
paren, call read once, and the return value of read will be the sexp
at point.

Kai