Re: Parenthesis matching should consider the kind of parenthesis during pair-search

[Herman , Géza]

> > The only gain with the current way is that Emacs will point out
> > the mismatch (considering my Makefile example), if the cursor 
> > is
> > on the opening '('.  With my suggested method, it's not the
> > mismatch which would be shown, but the pair of '(' would (which 
> > is
> > actually a correct behavior in this case, the pair of '(' is
> > indeed the ')' ).
>
> OK, I don't agree with some of the things you're saying
I think I just wrote facts here.  If the matching algorithm were 
modified in the way I described, that would be the result.  Which 
parts do you not agree with?

> but why don't you implement your idea so that we can try it out?
If it's an easy thing to do for someone who doesn't really know 
Emacs's codebase too much, I can do that.  But, tbh, it shouldn't 
be too hard to imagine how it worked.  Also, all the other editors 
I know works similarly like I described.  So it's easy to try this 
out with other editors.

> > If you put the cursor on the '}', Emacs would still show that 
> > it
> > is a paren without a pair, just like now (but instead of saying
> > that its "pair" is the '(', it wouldn't show anything, because 
> > '}'
> > doesn't have a pair.
>
> What if earlier on in the file there were a
>
>     ({)
>
> ?  Should your new way of matching find that {?  Or would the 
> enclosing
> ( and ) prevent this being a match?  If so, what are the exact 
> criteria?
It would find it.  My suggested algorithm is simple: when 
searching for a pair of '{', the algorithm should only consider 
'{' and '}'. All the other kind of parens should be ignored. 
That's it.

> > Why is it a desired thing that Emacs should show some 
> > mismatching
> > paren if the cursor is on a completely unrelated paren?
>
> Emacs doesn't have the facilities to determine that the 
> mismatching
> paren is "completely unrelated".
Emacs already tells that '(' and '}' are unrelated, because it 
shows them as mismatching.  I don't think that there should be any 
sophisticated facilities to determine unrelatedness.  If the paren 
Emacs find is a mismatching one, then it should continue finding 
the proper pair, that's it.

> It's fairly likely to be a typo.
Yes, that is an example that I can accept.  But I don't think that 
this is a very common thing.  At least, for me, this Emacs 
behavior was never useful.  But it annoys me that sometimes I 
cannot move to the pair of a paren because of this behavior.

But thinking about it further, maybe this problem shouldn't be 
solved like this, because there is a better solution: 
makefile-mode should be more clever - if it is possible - to not 
mark } as a paren in my example case, because from the semantics 
of the Makefile viewpoint, it is not actually a paren, '}' should 
behave like if it were in a string.