Re: Re: Backreferences in source-highlight 2.7

gnombat wrote:
> Lorenzo Bettini wrote:
>> gnombat wrote:
>>> I'm having trouble with backreferences in source-highlight 2.7.  If I
>>> create a language definition file named foo.lang:
>>>
>>> keyword = `a(.)\1`
>>>
>>> And then I create a test file example.foo:
>>>
>>> aaa abb acc a** a@@
>>>
>>> And then I run source-highlight:
>>>
>>> source-highlight --lang-def=foo.lang example.foo
>>>
>>> Then "aaa", "abb" and "acc" are highlighted, but "a**" and "a@@" are
>>> not.  Shouldn't the dot match any character?
>>
>> yes you're right, so this must be a bug...
>>
>> I'll try to work on it tomorrow
>>
>> thanks for the feedback!
>> cheers
>>     Lorenzo
>>
> 
> I think I figured out what is going on: is_to_isolate from 
> regexpstatebuilder.cpp is treating the regular expression as an 
> alphanumerical string because `a(.)\1` starts and ends with a letter or 
> number.
> 
> /**
>  * An expression is isolated basically if it is an alphanumerical
>  * string
>  * TODO check whether this is actually correct in principle
>  * @param s
>  * @return
>  */
> bool is_to_isolate(const string &s) {
>   if (s.size()) {
>     if ((isalnum(s[0]) || s[0] == '_') && (isalnum(s[s.size()-1]) || 
> s[s.size()-1] == '_'))
>       return true;
>   }
> 
>   return false;
> }
> 
> Then the whole regular expression gets surrounded with word boundary 
> characters.  This causes the match to fail with "a**" and "a@@".

Yes you're right!

I'll have to fix the code calling is_to_isolate (in the case of a ` ` 
is_to_isolate probably should not be called at all)

hope to have a fix soon
thanks again
	Lorenzo

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Lorenzo Bettini, PhD in Computer Science, DSI, Univ. di Firenze
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