Re: font-lock as a single command

[Christopher Dimech]

I do not know how good the following defun is to disable the lowering
and raising typeface.  I got it from "tex-mode.el" but do not really
know how to use it.

(defun supinf-disable-cruc (beg end)
  "Set typeface for text between BEG and END."
  (font-lock-default-unfontify-region beg end)
  (while (< beg end)
    (let ((next (next-single-property-change beg 'display nil end))
          (prop (get-text-property beg 'display)))
      (if (and (eq (car-safe prop) 'raise)
               (member (car-safe (cdr prop)) deviat-supinf)
               (null (cddr prop)))
          (put-text-property beg next 'display nil))
      (setq beg next))))

> Sent: Saturday, February 13, 2021 at 12:58 PM
> From: "Christopher Dimech" <dimech@gmx.com>
> To: moasenwood@zoho.eu
> Cc: help-gnu-emacs@gnu.org
> Subject: Re: font-lock as a single command
>
> I have the following three defun
> 
> "supinf-match" matches superscript and subscript code structures.
> In the following example "\alpha^{ijk} \beta_{pqr}", {ijk} is
> rained in height, whereas {pqr} is lowered in height. 
> The raising and lowering is achieved by calling "supinf-raise-cruc".
> 
> "supinf-enable" sets the new typeface using "font-lock-add-keywords".
> I also want a function that disables the raising and lowering, returning
> the buffer to how it was before "supinf-enable" was called.
> 
> 
> (defun supinf-raise-cruc (pos)
>   "Raise and lower typeface at position POS."
>   (unless (or (memq (get-text-property pos 'face)
>                   '(font-lock-constant-face font-lock-builtin-face))
>             ;; Check for backslash quoting
>             (let ((odd nil) (pos pos))
>               (while (eq (char-before pos) ?\\)
>                 (setq pos (1- pos) odd (not odd)))
>               odd))
>     (if (eq (char-after pos) ?^)
>       `(face supr-tfc display (raise ,(car deviat-supinf)))
>       `(face infr-tfc display (raise ,(cadr deviat-supinf))) )))
> 
> (defun supinf-match (limit)
>   "Match superior and inferior glyph patterns up to LIMIT."
>   (when (and supinf-signal
>            (re-search-forward "[_^] *\\([^\n\\{}]\\|\
> \\\\\\([a-zA-Z@]+\\|[^ \t\n]\\)\\|\\({\\)\\)" limit t))
>     (when (match-end 3)
>       (let ((beg (match-beginning 3))
>           (end (save-restriction
>                  (narrow-to-region (point-min) limit)
>                  (condition-case nil
>                      (scan-lists (point) 1 1) (error nil)))))
>       ;; body of let
>       (store-match-data
>            (if end
>              (list (match-beginning 0) end beg end)
>            (list beg beg beg beg)))))
>     t))
> 
> (defun supinf-enable ()
>   "Enables a typeface for displaying tex commands."
>   (setq supinf-signal t)
>   ;; Syntax for font-lock-add-keywords is
>   ;;   (font-lock-add-keywords MODE KEYWORDS &optional HOW)
>   (font-lock-add-keywords nil
>      '(  (supinf-match (1 (supinf-raise-cruc (match-beginning 0)))) )
>      t))
> 
> 
> 
> > Sent: Saturday, February 13, 2021 at 12:08 PM
> > From: "Emanuel Berg via Users list for the GNU Emacs text editor" 
> > <help-gnu-emacs@gnu.org>
> > To: help-gnu-emacs@gnu.org
> > Subject: Re: font-lock as a single command
> >
> > Christopher Dimech wrote:
> > 
> > > (font-lock-add-keywords MODE KEYWORDS &optional HOW)
> > >
> > > What does the optional HOW actually do?
> > 
> > It is actually described in the docstring:
> > 
> >   If optional argument HOW is ‘set’, they are used to replace
> >   the current highlighting list. If HOW is any other non-nil
> >   value, they are added at the end of the current
> >   highlighting list.
> > 
> > -- 
> > underground experts united
> > http://user.it.uu.se/~embe8573
> > https://dataswamp.org/~incal
> > 
> > 
> >
> 
>