copy-region-to-variable

copy-region-to-variable

[hans nieuwenhuizen]

None of the almost 2000 built-in functions of emacs 21.2 seems to copy part
of the buffer ( region ) into a variable.

You need that e.g. if you have to enlarge the double in the region by a
factor of
say 3.456 .

Can anybody tell me how to do that?



--
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Prof. Ir. j.k. nieuwenhuizen                 email: hans@nieuwenhuizen-jk.nl
dom Paul Bellotweg 8
5624 KZ Eindhoven - NL

Tel [{++31|0}40]2442226
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Re: copy-region-to-variable

[Joakim Hove]

"hans nieuwenhuizen" <j.k.nieuwenhuizen@tue.nl> writes:

> None of the almost 2000 built-in functions of emacs 21.2 seems to copy part
> of the buffer ( region ) into a variable.
>
> You need that e.g. if you have to enlarge the double in the region by a
> factor of
> say 3.456 .

If you just mean the text content of the buffer you can use

(buffer-substring p1 p2)

or

(buffer-substring-no-properties p1 p2) 

which return the buffer-content between p1 and p2.

HTH Joakim

Untested:
---------

(defun enlarge-double (p1 p2)
  (interactive "r")
  (let  ((new-number    (* 3.456 (string-to-number  (buffer-substring-no-properties p1 p2)))))
     (kill-region p1 p2)
     (goto-char p1)
     (insert (format "%s" new-number))))   
         

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Re: copy-region-to-variable

[Johan Bockgård]

Joakim Hove <hove@bccs.no> writes:

>      (kill-region p1 p2)

(delete-region p1 p2) ; thou shalt not (mess with the) kill (ring)

Also consider:

     - Function: delete-and-extract-region start end
    
         This function deletes the text between positions START and
         END in the current buffer, and returns a string containing
         the text just deleted.
    
         If point was inside the deleted region, its value afterward
         is START. Otherwise, point relocates with the surrounding
         text, as markers do.
    
-- 
Johan Bockgård

Re: copy-region-to-variable

[Gareth Rees]

Hans Nieuwenhuizen wrote:
> None of the almost 2000 built-in functions of emacs 21.2 seems to copy
> part of the buffer (region) into a variable.

As others have said, 'buffer-substring' gives you a substring of a
buffer.  However, you don't need that to solve your problem.

> You need that e.g. if you have to enlarge the double in the region by
> a factor of say 3.456.  Can anybody tell me how to do that?

If you want to do this interactively, use 'query-replace-regexp-eval'.
For example, to multiply each number by 3.456, type:

    M-x query-replace-regexp-eval RET
    [0-9.]+ RET
    (* 3.456 (string-to-number \0)) RET

Non-interactively, you'd write Lisp like this:

    (while (re-search-forward "[0-9]+\\(\\.[0-9]+\\)?" nil t)
      (replace-match
        (number-to-string (* 3.456 (string-to-number (match-string 0))))))

(Note that you need to be a bit more careful with the regexp for numbers
when you're not interactive, and you need 'number-to-string'.)

-- 
Gareth Rees