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Re: Proposed extension of show-paren-mode: Highlight parens when point i
From: |
Stefan Monnier |
Subject: |
Re: Proposed extension of show-paren-mode: Highlight parens when point is in L or R margin. |
Date: |
Sun, 12 Oct 2014 00:12:12 -0400 |
User-agent: |
Gnus/5.13 (Gnus v5.13) Emacs/24.4.50 (gnu/linux) |
> So: If point is in the LH margin of the code, highlight the first paren
> on the line and its match, or failing that, the last paren on the line
> with its match.
Related ideas:
- show matching paren when point is right after the open paren or right
before the close paren. (see
http://stackoverflow.com/questions/25648067/emacs-matching-parenthesis-when-cursor-is-on-closing-parenthesis
for a 5-liner which does that).
- show matching paren, when there's only whitespace between point and
the open/close paren.
This second idea is a superset of the one you suggest. I personally
don't use show-paren-mode because I find it distracting, so maybe
a superset would be too distracting.
> Then again, why not do the same if point is in a line comment?
Sorry, I don't know what "in a line comment" means.
As for your patch, I'd rather see the new code moved to a new function.
See more detailed comments below.
Stefan
> + (defcustom show-paren-when-point-in-margin nil
Please don't call it "margin".
> ! (cond
> ! ;; Point is at a paren.
> ! ((eq (syntax-class (syntax-after (1- (point)))) 5)
> ! (setq dir -1))
> ! ((eq (syntax-class (syntax-after (point))) 4)
> ! (setq dir 1))
> ! ;; Point is in the LH margin.
> ! ((and show-paren-when-point-in-margin
> ! (< (point) ind-pos))
> ! (cond
> ! ((eq (syntax-class (syntax-after ind-pos)) 4)
> ! (setq dir 1
> ! oldpos ind-pos))
> ! ((eq (syntax-class (syntax-after ind-pos)) 5)
> ! (setq dir -1
> ! oldpos (1+ ind-pos)))
> ! ((eq (syntax-class (syntax-after (1- eol-pos))) 4)
> ! (setq dir 1
> ! oldpos (1- eol-pos)))
> ! ((eq (syntax-class (syntax-after (1- eol-pos))) 5)
> ! (setq dir -1
> ! oldpos eol-pos))))
> ! ;; Point is in a comment or whitespace to the right of the line.
> ! ((and show-paren-when-point-in-margin
> ! (>= (point) eol-pos))
> ! (cond
> ! ((eq (syntax-class (syntax-after (1- eol-pos))) 4)
> ! (setq dir 1
> ! oldpos (1- eol-pos)))
> ! ((eq (syntax-class (syntax-after (1- eol-pos))) 5)
> ! (setq dir -1
> ! oldpos eol-pos)))))
It's not at all clear to me why there has to be so many different cases
(IOW we'd need a comment that explains why we need such complexity).
> ! (when dir
> ! (setq unescaped
> ! (= (if (= dir -1) 1 0)
> ! (logand 1 (- oldpos
> ! (save-excursion
> ! (goto-char oldpos)
> ! (if (= dir -1) (backward-char))
> ! (skip-syntax-backward "/\\")
> ! (point)))))))
This is a code duplication. Please move it to a separate helper function.
Stefan
Re: Proposed extension of show-paren-mode: Highlight parens when point is in L or R margin.,
Stefan Monnier <=
- Re: Proposed extension of show-paren-mode: Highlight parens when point is in L or R margin., Alan Mackenzie, 2014/10/12
- Re: Proposed extension of show-paren-mode: Highlight parens when point is in L or R margin., Stefan Monnier, 2014/10/14
- Re: Proposed extension of show-paren-mode: Highlight parens when point is in L or R margin., John Yates, 2014/10/14
- Re: Proposed extension of show-paren-mode: Highlight parens when point is in L or R margin., Alan Mackenzie, 2014/10/15
- Re: Proposed extension of show-paren-mode: Highlight parens when point is in L or R margin., Andy Moreton, 2014/10/15
- Re: Proposed extension of show-paren-mode: Highlight parens when point is in L or R margin., Stefan Monnier, 2014/10/15
- Re: Proposed extension of show-paren-mode: Highlight parens when point is in L or R margin., Alan Mackenzie, 2014/10/16
- Re: Proposed extension of show-paren-mode: Highlight parens when point is in L or R margin., Stefan Monnier, 2014/10/16
- Re: Proposed extension of show-paren-mode: Highlight parens when point is in L or R margin., Alan Mackenzie, 2014/10/16
- Re: Proposed extension of show-paren-mode: Highlight parens when point is in L or R margin., Stefan Monnier, 2014/10/16