Re: replace-regexp question

[David Kastrup <dak@gnu.org>]

Giorgos Keramidas <keramida@ceid.upatras.gr> writes:

> David Kastrup <dak@gnu.org> writes:
>>Neon Absentius <absent@sdf.lonestar.org> writes:
>>> Is there a way to use the command replace-regexp to replace a number with
>>> that number increased, say, by 15?  I tried
>>>
>>> C-M-% -?[0-9]+ RET (number-to-string (+ (string-to-number "\&") 15)) RET
>>>
>>> but it doesn't work because emacs interprets the second input to be
>>> a string and so it doesn't evaluate it.  So I guess the question is
>>> how can we use the result of evaluating a sexp for replacement text?
>>>
>>> Any help and/or pointers to documentation will be greatly
>>> appreciated.
>>
>> The development version of Emacs would offer
>> C-M-% -?[0-9]+ RET \,(+ \#& 15) RET
>
> Oh, heh!  Very neat ;)

The example in the Emacs manual is more amusing in my opinion, but
then I am biased.

       For computing replacement strings for `\,', the `format' function is
    often useful (*note Formatting Strings: (elisp)Formatting Strings.).
    For example, to add consecutively numbered strings like `ABC00042' to
    columns 73 to 80 (unless they are already occupied), you can use

         M-x replace-regexp <RET> ^.\{0,72\}$ <RET>
         \,(format "%-72sABC%05d" \& \#) <RET>


-- 
David Kastrup, Kriemhildstr. 15, 44793 Bochum