end-of-line $ in multiline regexp replace

end-of-line $ in multiline regexp replace

[Leo]

hi there

want to replace a multiline regexp by an one-line replacement. (in fact i
just want to delete the line with the regexp.)

so, at first i tried:
        (query-replace-regexp ".*bytes.*$[ctrl-q][ctrl-j]" "" nil nil nil)
which did not find any line. :-(

then i just tried the same without the end-of-line "$":
        (query-replace-regexp ".*bytes.*[ctrl-q][ctrl-j]" "" nil nil nil)
and that worked.

i don't understand, why? the first regexp ".*bytes.*$[ctrl-q][ctrl-j]" seems
to me even >>more valid<< then the second one.

any explanations?

tanks and cheers, leo

Re: end-of-line $ in multiline regexp replace

[Alan Mackenzie]

Leo <leo.broska@nospam.isys.com.au> wrote on Fri, 31 Oct 2003 11:22:25 +1100:
> hi there

> want to replace a multiline regexp by an one-line replacement. (in fact i
> just want to delete the line with the regexp.)

> so, at first i tried:
>         (query-replace-regexp ".*bytes.*$[ctrl-q][ctrl-j]" "" nil nil nil)
> which did not find any line. :-(

> then i just tried the same without the end-of-line "$":
>         (query-replace-regexp ".*bytes.*[ctrl-q][ctrl-j]" "" nil nil nil)
> and that worked.

> i don't understand, why? the first regexp ".*bytes.*$[ctrl-q][ctrl-j]" seems
> to me even >>more valid<< then the second one.

> any explanations?

Yes.  It's on the page "Regexp Special" in the Elisp manual:

:      For historical compatibility reasons, `$' can be used only at the
:      end of the regular expression, or before `\)' or `\|'.

I think this is crazy, but there you go.  There is no matching warning on
the corresponding page ("Regexps") in the Emacs manual (at least, there
wasn't in October 2001), which seems like a bug to me.

A workaround is to enclose such a `$' in parentheses:  "\($\)" [or
"\\($\\)" if you're writing it as a string in a Lisp program].

> tanks and cheers, leo

-- 
Alan Mackenzie (Munich, Germany)
Email: aacm@muuc.dee; to decode, wherever there is a repeated letter
(like "aa"), remove half of them (leaving, say, "a").

Re: end-of-line $ in multiline regexp replace

[Edward Dodge]

"Leo" <leo.broska@NOSPAM.isys.com.au> writes:

> hi there
>
> want to replace a multiline regexp by an one-line replacement. (in fact i
> just want to delete the line with the regexp.)
>
> so, at first i tried:
>         (query-replace-regexp ".*bytes.*$[ctrl-q][ctrl-j]" "" nil nil nil)
> which did not find any line. :-(
>
> then i just tried the same without the end-of-line "$":
>         (query-replace-regexp ".*bytes.*[ctrl-q][ctrl-j]" "" nil nil nil)
> and that worked.
>
> i don't understand, why? the first regexp ".*bytes.*$[ctrl-q][ctrl-j]" seems
> to me even >>more valid<< then the second one.
>
> any explanations?
>
> tanks and cheers, leo

The $ meta-character represents the very end of a line, which would
include the newline character.  Whereas C-q C-j is a regular
expression for the newline character.  My guess is that $ marks the
very end of the line (INCLUDING the newline character) and so your
regexp is actually the equivalent of this:

".*bytes.*[ctrl-q][ctrl-j][ctrl-q][ctrl-j]"

-- 
Edward Dodge

/GNU Emacs 21.3.50.1 (powerpc-apple-darwin5.5) of 2002-10-11 on G3/