Re: parse-partial-sexp to stop at any depth change (and Re: Fontifying outside of region passed to registered JIT lock function)

[Stefan Monnier]

>> insert a "display only" close-paren (with suitable coloring).
> There's probably less potential to cause user confusion if it colors
> existing parens rather than color parens that are not really a part of
> the file content.

But if that existing paren is before window-start, the user won't see
it.  Using fake close-parens might not be the best choice, but I think
the idea of having some visual indicator saying "not enough
whitespace here or missing close parens on previous lines" between BOL
and the first non-whitespace char can be workable.  This visual
indicator can be to just highlight the indentation space, but as you say
there might not be any indentation space, so inserting a display-only
char can be a good solution.  Now which char to use is up to you.

> One issue is my usage of parse-partial-sexp. This function's interface
> doesn't make it easy to stop if there's a change of depth either up or
> down, so for code simplicity I went one char at a time:

>   (parse-partial-sexp (point)
>                       (1+ (point))
>                       nil
>                       nil
>                       parse-state
>                       nil)

Yuck!  Look at (nth 9 (syntax-ppss)): it's a list of the positions of
the open-parens that aren't closed yet.


        Stefan