How to highlight the matching reqular expression strings

How to highlight the matching reqular expression strings

[Anand Dhanakshirur]

Hi Bastien,
Thanks,
It worked for regexp like als.bd(any character).
It highlighted the matching strings.
But it did not work for als*bd(mutliple characters).
It did not highlight the matching strings.
How to do this?

Do
Bastien wrote:
> Anand Dhanakshirur <asd@cdotb.ernet.in> writes:
>
>  
>> Kindly tell me How to do regular expression seach in emacs buffer.
>> for ex: i want to know(highlight) the all the text which are als*.
>>     
>
> C-u C-s a l s *
>
>   

Re: How to highlight the matching reqular expression strings

[thierry.volpiatto]

Hi,
Anand Dhanakshirur <asd@cdotb.ernet.in> writes:

> Hi Bastien,
> Thanks,
> It worked for regexp like als.bd(any character).
> It highlighted the matching strings.
> But it did not work for als*bd(mutliple characters).
> It did not highlight the matching strings.
> How to do this?

May be you misunderstand the use of * here, that do not have the same
meaning that in shell like *.el.(globbing).

,----
| `*'
|      is not a construct by itself; it is a postfix operator that means
|      to match the preceding regular expression repetitively as many
|      times as possible.  Thus, `o*' matches any number of `o's
|      (including no `o's).
| 
|      `*' always applies to the _smallest_ possible preceding
|      expression.  Thus, `fo*' has a repeating `o', not a repeating
|      `fo'.  It matches `f', `fo', `foo', and so on.
`----

Have a look at the elisp manual about regexps.

[eval - C-x C-e] ==> (info "(elisp)Regexp Special")

> Do
> Bastien wrote:
>> Anand Dhanakshirur <asd@cdotb.ernet.in> writes:
>>
>>  
>>> Kindly tell me How to do regular expression seach in emacs buffer.
>>> for ex: i want to know(highlight) the all the text which are als*.
>>>     
>>
>> C-u C-s a l s *
>>
>>   
>
>
>
>

-- 
A + Thierry Volpiatto
Location: Saint-Cyr-Sur-Mer - France

Re: How to highlight the matching reqular expression strings

[Giorgos Keramidas]

On Tue, 17 Mar 2009 09:59:27 +0530, Anand Dhanakshirur <asd@cdotb.ernet.in> wrote:
>>> Kindly tell me How to do regular expression seach in emacs buffer.
>>> for ex: i want to know(highlight) the all the text which are als*.
>>>     
>>
>> C-u C-s a l s *
>
> Hi Bastien,
> Thanks,
> It worked for regexp like als.bd(any character).
> It highlighted the matching strings.
> But it did not work for als*bd(mutliple characters).
> It did not highlight the matching strings.
> How to do this?

The '*' character has a special meaning in reguar expressions.  It means
`zero or more occurences of the last regular expression part'.  So, when
you try to highlight `als*bd' it will match with `albd', `alsbd', and
`alssbd' but not with `als?bd' where '?' is any other character than 's'.

Try running `M-x highlight-regexp RET als.*bd RET'  The extra '.' before
the special '*' character means `any character', so this will match text
like `alsbd', `alsabd', `alsbbd', ..., `alsaabd', `alsabbd', `alsacbd',
and so on.