regexp problem

regexp problem

[Þorne]

Is there a way to match only `b' if and only if it appears in the
context `abc'  ?

So searching `foo abc b ' would return a match of `b' but `bar xbc'
would not return any matches.

Re: regexp problem

[Pascal Bourguignon]

"Þorne" <ego111@gmail.com> writes:

> Is there a way to match only `b' if and only if it appears in the
> context `abc'  ?
>
> So searching `foo abc b ' would return a match of `b' but `bar xbc'
> would not return any matches.

You can match groups:

a\(b\)c

so the match number 0 is the whole regexp: abc
but the match number 1 is only b


-- 
__Pascal Bourguignon__                     http://www.informatimago.com/

"Debugging?  Klingons do not debug! Our software does not coddle the
weak."

Re: regexp problem

[Þorne]

Pascal Bourguignon wrote:
> You can match groups:
>
> a\(b\)c
>
> so the match number 0 is the whole regexp: abc
> but the match number 1 is only b

Sorry to be dense, but do you mean something like this:

(search-forward-regexp "a\\(b\\)c\\0")

because i can't get anything like it to work.  I don't really follow
the documentation for the \<digit> construct in regexps at all...

In fact the code above finds a string that looks like `abc0' instead of
just `b'.

Specifically i am trying to make a regexp for define-generic-mode to
colorize the string`*' but only if it is in a string that looks like
`(*)'.  But not colorize the surrounding parens.

Re: regexp problem

[Pascal Bourguignon]

"Þorne" <ego111@gmail.com> writes:

> Pascal Bourguignon wrote:
>> You can match groups:
>>
>> a\(b\)c
>>
>> so the match number 0 is the whole regexp: abc
>> but the match number 1 is only b
>
> Sorry to be dense, but do you mean something like this:
>
> (search-forward-regexp "a\\(b\\)c\\0")


(when (search-forward-regexp "a\\(b\\)c")
  (let ((all    (match-string 0))
        (only-b (match-string 1)))
    (goto-char (match-end 0))
    (insert (format "\nall = %s\nonly-b = %s\n" all only-b))))



> because i can't get anything like it to work.  I don't really follow
> the documentation for the \<digit> construct in regexps at all...
>
> In fact the code above finds a string that looks like `abc0' instead of
> just `b'.
>
> Specifically i am trying to make a regexp for define-generic-mode to
> colorize the string`*' but only if it is in a string that looks like
> `(*)'.  But not colorize the surrounding parens.

Read with utmost attention the help about the variable font-lock-keywords.

 (MATCHER . SUBEXP)

 ("fu\\(bar\\)" . 1)	substring "bar" within all occurrences of "fubar" in
                       	the value of `font-lock-keyword-face'.


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__Pascal Bourguignon__                     http://www.informatimago.com/

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expressed or implied.

Re: regexp problem

[Þorne]

Pascal Bourguignon wrote:
> "Þorne" <ego111@gmail.com> writes:
>
> > Pascal Bourguignon wrote:
> >> You can match groups:
> >>
> >> a\(b\)c
> >>
> >> so the match number 0 is the whole regexp: abc
> >> but the match number 1 is only b
> >
> > Sorry to be dense, but do you mean something like this:
> >
> > (search-forward-regexp "a\\(b\\)c\\0")
>
>
> (when (search-forward-regexp "a\\(b\\)c")
>   (let ((all    (match-string 0))
>         (only-b (match-string 1)))
>     (goto-char (match-end 0))
>     (insert (format "\nall = %s\nonly-b = %s\n" all only-b))))
>
>
>
> > because i can't get anything like it to work.  I don't really follow
> > the documentation for the \<digit> construct in regexps at all...
> >
> > In fact the code above finds a string that looks like `abc0' instead of
> > just `b'.
> >
> > Specifically i am trying to make a regexp for define-generic-mode to
> > colorize the string`*' but only if it is in a string that looks like
> > `(*)'.  But not colorize the surrounding parens.
>
> Read with utmost attention the help about the variable font-lock-keywords.
>
>  (MATCHER . SUBEXP)
>
>  ("fu\\(bar\\)" . 1)	substring "bar" within all occurrences of "fubar" in
>                        	the value of `font-lock-keyword-face'.

Ah!  Thank you!  Got it finally.

(Turned out specifically what i needed for doing it (with
font-lock-type-face in my case) was:

(define-generic-mode 'foo
nil nil

(list
blah-blah
  '("(\\(\\*\\))" 1 font-lock-type-face))

blah-blah))

Thanks again!