Re: cannot disable paren matching

[John Mastro]

Don Woods <don@icynic.com> wrote:
> I am having a problem where paren matching is not working as desired,
> and I am unable either to turn it off or to make it work correctly.
>
> The specific case where I'm having trouble is in PostScript mode,
> when also in Overwrite mode.  When I type a character that acts as a
> close paren -- such as > or } -- the character is inserted instead of
> overwriting the current char.  Emacs briefly highlights the matching
> open paren, or reports a mismatch, as the case may be, but does NOT
> remove the char I was intending to overwrite.
>
> Since I don't especially need the paren highlighting in my current
> editing, most of my attempts to work around this bug have involved
> trying to disable the paren-matching behavior.  I have tried such
> things as
>
> (show-paren-mode 0)     ;; no noticeable change
>
> (show-paren-mode nil)   ;; no longer shows matching open
>                         ;; but still does not overwrite
>
> (modify-syntax-entry ?> "w" ps-mode-syntax-table)
>                         ;; > now highlights the char AFTER the matching <
>                         ;; but still does not overwrite
> (modify-syntax-entry ?< "w" ps-mode-syntax-table)
>                         ;; when combined with previous, > goes back to
>                         ;; showing matching <, but still does not overwrite
>
> I know I've tinkered with other paren-related vars without success,
> but no longer recall everything I tried.
>
> My only successful workaround so far is to scrap postscript-mode and
> use fundamental-mode.  I'm using overwrite-mode while editing a portion
> of the PostScript file that is a block of "ascii art" data, so don't
> really need postscript-mode there, but it's awkward when switching
> between the data and code portions of the file.
>
> Note: emacs-version is:
> "GNU Emacs 22.1.1 (mac-apple-darwin)
>  of 2016-04-22 on osx143.apple.com"

I'm not totally sure I understand the scenario, but I tried to reproduce
this in Emacs 25 using the steps below and everything seemed to work as
intended. Specifically, at the end of the steps, the buffer contained
"a{b}c{d}".

Here are the steps I tried:
  emacs -Q
  C-x b ps RET
  M-x ps-mode RET
  M-x show-paren-mode RET
  M-x overwrite-mode RET
  foo{bar}
  C-a
  a{b}c{d}

If my recipe above would indeed trigger the problem you're describing,
perhaps using a newer version of Emacs would do the trick - Emacs 22 is
quite old (circa 2006 I believe).

If the recipe above does not capture the problem, can you provide
similar steps from "emacs -Q" that we can experiment with?

        John