Re: regexp for scheme blocks in lilypond language

On 01/18/2012 11:55 PM, Federico Bruni wrote:
> Il 18/01/2012 10:01, Lorenzo Bettini ha scritto:
>> On 18/01/2012 09:54, Federico Bruni wrote:
>>> Hi,
>>>
>>> lilypond files can contain blocks of scheme code in several ways.
>>> The main challenge is handling conflicts between single and multiline
>>> and especially blocks where the number of parentheses cannot be known in
>>> advance (there's a way to match balanced parentheses?).
>>
>> Hi
>>
>> very quick answer: you can match balanced parenthesis using 'nested'
>> (see the documentation);
>>
>
> Thanks, this should be the direction, but it's not so easy.
> First, the doc says:
>
> "Note that, in order for a delimited language element to be nested, its
> starting and ending elements must be different"
>
> I may be wrong, but I would add: they also have to be specular.
> In my case delimiters are not specular.

no, that's not requested :)
note that end delimiter may refer to start delimiter (using the regex 
syntax for referring the matched part of another expression); this is 
the case for lua.lang where nested comments can have different syntax 
and the delimiter has to match the starting delimiter and refers to it 
(with this respect, source-highlight is pretty powerful, but I may be 
biased ;)

> Start delimiter: #(
> End delimiter: )
>
> I can't consider just parenthesis for two reasons:
>
> - I want to highlight # as well
> - ( and ) have also a different meaning (slurs) in lilypond synthax and
> must be highlighted differently
>
> So this doesn't work:
> scheme_block delim "(" ")" multiline nested
>
> I wrote this but it doesn't work correctly:
>
> scheme_block delim '(?<!#)\(' '\)' multiline nested
>
> The most external () block is omitted and slurs higlighting is broken
> (see file attached).
>
> What do you recommend to do?

you can (but I haven't tested it) have an 'environment/state' which uses 
'start' that matches '#' followed by '(' (but '(' is not consumed, using 
lookahead) and inside this environment have the 'delim' environment... 
this will let you highlight # differently...

hope to hear from you soon
cheers
	Lorenzo

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Lorenzo Bettini, PhD in Computer Science, DI, Univ. Torino
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