Re: scratch/fontify-open-string. [Was: CC Mode and electric-pair "problem".]

[Stephen Leake]

Alan Mackenzie <address@hidden> writes:

> Hello, Stephen.
>
> Many thanks for trying out and testing this branch.

You're welcome; thanks for implementing it.

> I'm afraid I've found a rather large snag - there are backward moving
> commands and functions in Emacs which bypass proper syntax checking.
> For example, in the following in (the modified) shell-script-mode:
>
> 1.    foo="Foo"
> 2.    bar="Bar
> 3.
>
> , with point at BOL3, a C-M-b moves to the F, rather than "Bar.
>
> This is because (forward-comment -1) crashes into the "whitespace" at
> the end of L2 (the newline) rather than taking account of its syntax
> (the string closing flag).
>
> At the very least, the function back_comment (in src/syntax.c) will need
> to be modified to take account of such things, and in doing so, might as
> well become a function that also goes back over EOL-terminated strings,
> as Stefan suggested.  This will be a lot of work.
>
> I fear there may be several, or even many, lisp functions in Emacs which
> may likewise need modifying.
>
> The root cause of this problem, in the abstract, is that Emacs attempts
> to scan backwards over strings and comments, which is only heuristically
> possible, rather than scanning forwards over the same constructs and
> remembering the endpoints.
>
> Right at the moment, I don't know how to proceed.  Sorry.

I think you are opposed to syntax-ppss, but that does scan forward and
remember things; can we use that here?

-- 
-- Stephe