[texworks] syntax-patterns.txt

[Paul A Norman]

Thanks very much Stefan,

Paul

On 3 June 2011 22:52, Stefan Löffler <st.loeffler at gmail.com> wrote:
> Hi,
>
> On 2011-06-03 04:48, Paul A Norman wrote:
>> Just wanted to check a couple of things please - got  into a mind maze
>> with this stuff.
>
> Yeah, that can happen terribly easily with regexps ;).
>
>> With syntax-patterns.txt which dialect of regular expressions is being
>> used please?
>
> The Qt dialect (http://doc.trolltech.com/4.7/qregexp.html#details). In
> fact, the string given in syntax-patterns.txt is simply wrapped into a
> QRegExp object (see src/TeXHighlighter.cpp at 226).
>
>> In that dialect does .* mean  anything many times?
>
> Yes, anything zero or more times (one or more would be .+). The
> quantifiers are also greedy (they match as much as they possibly can).
>
>> Can () be used to choose which part of an expression is colourised?
>> For e.g.
>>
>> skyblue N .*\{(http[s]://.*)}
>>
>>     -- Would colour only the actual address?
>
> No, not at the moment, unfortunately. It should be possible to use
> look-ahead assertions to match a string only if it followed by a certain
> string (without including the second in the match), but look-behind
> assertions are not supported, unfortunately.
>
> In principle, colorizing the captured text could probably be added to
> the code, but it would have drawbacks for people who are lazy and just
> write, e.g., "(W|w)arning" instead of "(?:W|w)arning".
>
> BTW: You probably want something like "\{(https?://[^}]*)\}".
>
> HTH
> Stefan
>