Re: Writing syntax-propertize-function for strings in code in strings, etc

[Dmitry Gutov <dgutov@yandex.ru>]

On 27.10.2012 0:41, Stefan Monnier wrote:
>>> Yes, one "push <inner-syntax-table>" and one "pop".
>> So, I don't see the usefulness of the <inner-syntax-table> value in the
>> simple case of embedding code in the same language.
>
> It's for the other cases: strings with strings and comments within strings.

Okay. I guess I just don't know [well enough] any languages with 
different embedded syntaxes.

>> Unless we're doing something like the "multiple-modes" use case, which we
>> discussed in another thread.
>
> Yes, it potentially could be used for m-m-m, tho it would only be
> a piece of the puzzle (and it's not clear how useful that piece would be
> in the end, once we have the whole puzzle).

It will help with third-party frameworks, at least, which is what we 
discussed back then, that (syntax-ppss) will return reasonable values.

>>> Of course, this is fine for parse-partial-sexp, but it's a different
>>> matter for backward-sexp, where the "pop" would also need to know the
>>> <inner-syntax-table>.
>> Maybe in the latter case the scanning function, when encountering the "pop"
>> syntax property, would just skip ahead until it finds the corresponding
>> "push"?
>
> Without knowing the inner syntax table, it's pretty difficult to know
> what can be skipped (unless we assume that the "push" can only be marked
> with a `syntax-table' text-property).

Indeed. But I think it's a reasonable assumption. In all cases I can 
think about the "region opener" is at least two characters long, and it 
often depends on the context (like only inside a string).

But suppose "push" characters can be set inside a syntax table.
Let's move point inside an embedded code region, maybe several levels 
deep. Now we want to call `forward-sexp'. How will it know the effective 
syntax-table value at that position?