Re: Bug Re: Greater than, less than bug in emacs-lisp source block

[John Kitchin <jkitchin@andrew.cmu.edu>]

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My previous solution seems like it stopped working for some reason. Here is
a new version that "should" only change syntax inside src-blocks, but not
inside strings.

It looks like this does not impact html blocks, or xml blocks.

It is probably possible to make it mode specific if needed.


(defun scimax-org-mode-<>-syntax-fix (start end)
  "Change syntax of characters ?< and ?> to symbol within source code
blocks."
  ;; I think this gets run in a special edit buffer for src-blocks. For now
I
  ;; only run this in the src blocks, so that outside the src-blocks these
still
  ;; act like b=open/close brackets.
  (when (org-src-edit-buffer-p)
    (let ((case-fold-search t))
      (goto-char start)
      ;; this "fixes" <>, {} and [] that fixes some issues in src blocks,
but
      ;; makes some new issues, which is now you cannot use them as
brackets.
      ;; this tries to be fancy and not change the syntax in strings.
      (while (re-search-forward "[[<{]\\|[]>}]" end t)
(unless (ppss-string-terminator (syntax-ppss (point)))
 (put-text-property (point) (1- (point))
                             'syntax-table (string-to-syntax "_")))))))


(defun scimax-fix-<>-syntax ()
  "Fix syntax of <> in code blocks.
This function should be added to `org-mode-hook' to make it work."
  (setq syntax-propertize-function 'scimax-org-mode-<>-syntax-fix)
  (syntax-propertize (point-max)))

(add-hook 'org-mode-hook
 #'scimax-fix-<>-syntax)


John

-----------------------------------
Professor John Kitchin (he/him/his)
Doherty Hall A207F
Department of Chemical Engineering
Carnegie Mellon University
Pittsburgh, PA 15213
412-268-7803
@johnkitchin
http://kitchingroup.cheme.cmu.edu



On Fri, Sep 3, 2021 at 9:47 AM Tim Cross <theophilusx@gmail.com> wrote:

>
> I think what is happening here is that org is bumping up against
> fundamental design limitations of Emacs. In basic terms, much of Emacs'
> underlying design is based on an assumption that a file only has a
> single major mode. Org works hard to get around this limitation, but it
> comes with cost - usually either performance or complexity.
>
> I think this could probably be characterised as a bug without a workable
> solution. While there are things youc an do, they all seem to have
> unwanted side effects. To what extent those side effect impact you
> depends on your use case (as John points out, if you have blocks of HTML
> or XML or JSX etc, changing the syntax table to make < and > 'normal'
> characters would fix the elisp issue, but break things in those source
> blocks.
>
> So really, what we have is an issue without a clean solution. Best
> anyone can do is select one of the proposed work-arounds which has
> minimal impact on the user. Personally, I never edit source blocks
> except in the special edit mode, so don't really notice the problem with
> mismatched parens.
>
> John Kitchin <jkitchin@andrew.cmu.edu> writes:
>
> > That is probably a matter of opinion.
> >
> > If you use angle brackets as delimiters, e.g. in html, xml in
> src-blocks, then the current syntax definition makes sense because
> > you can use them to find open and closing brackets, navigate them, etc..
> If you don't use those, it makes less sense, and maybe
> > isn't even something you want.
> >
> > John
> >
> > -----------------------------------
> > Professor John Kitchin (he/him/his)
> > Doherty Hall A207F
> > Department of Chemical Engineering
> > Carnegie Mellon University
> > Pittsburgh, PA 15213
> > 412-268-7803
> > @johnkitchin
> > http://kitchingroup.cheme.cmu.edu
> >
> > On Fri, Sep 3, 2021 at 7:42 AM Charles Millar <millarc@verizon.net>
> wrote:
> >
> >  Thank you, John.
> >
> >  I will give it a try.
> >
> >  However, is this a bug that should be fixed within org source code?
> >
> >  Charlie Millar
> >
> >  On 9/2/21 2:24 PM, John Kitchin wrote:
> >  > I think this issue is described in
> >  >
> https://emacs.stackexchange.com/questions/50216/org-mode-code-block-parentheses-mismatch
> .
> >  > There are also some solutions there.
> >  >
> >  >
> >  > John
> >  >
> >  > -----------------------------------
> >  > Professor John Kitchin (he/him/his)
> >  > Doherty Hall A207F
> >  > Department of Chemical Engineering
> >  > Carnegie Mellon University
> >  > Pittsburgh, PA 15213
> >  > 412-268-7803
> >  > @johnkitchin
> >  > http://kitchingroup.cheme.cmu.edu
> >  >
> >  >
> >  >
> >  > On Thu, Sep 2, 2021 at 2:10 PM Charles Millar <millarc@verizon.net>
> wrote:
> >  >
> >  >> Set up:
> >  >> GNU Emacs 28.0.50 (build 344, x86_64-pc-linux-gnu, GTK+ Version
> 3.24.23,
> >  >> cairo version 1.16.0) of 2020-12-31
> >  >> Org mode version 9.4.6 (release_9.4.6-637-gd70f28 @
> >  >> /usr/local/share/org-mode/lisp/)
> >  >>
> >  >> The following code will evaluate
> >  >>
> >  >> #+begin_src emacs-lisp
> >  >> (defun Foo ()
> >  >> (if (= 2 4) bar))
> >  >> #+end_src
> >  >>
> >  >> #+RESULTS:
> >  >> : Foo
> >  >> and the opening and closing parentheses match.
> >  >>
> >  >> If a greater than is inserted instead of equals, thus
> >  >>
> >  >> #+begin_src emacs-lisp
> >  >> (defun Foo ()
> >  >> (if (> 2 4) bar))
> >  >> #+end_src
> >  >>
> >  >> it apparently evaluates, however, the closing parenthesis immediately
> >  >> following the "4" is paired with the opening paren before "if" and
> not
> >  >> the opening paren immediately before the ">"
> >  >>
> >  >> A "less than" results with stranger parenthesis matching - the
> closing
> >  >> paren after the "4" matches no others; the closing paren immediately
> >  >> after "bar" matches the opening paren before "if"
> >  >>
> >  >> Charlie Millar
> >  >>
> >  >>
> >  >>
> >  >>
> >  >
>
>
>

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