Re: Separating colour and positioning functioning

[Christopher Dimech]

> Sent: Tuesday, February 09, 2021 at 9:37 AM
> 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: Separating colour and positioning functioning
>
> Christopher Dimech wrote:
> 
> > Have written a minor mode with part of the the code below
> > and want to modify tex-typeface-crucible so that the colour
> > scheme is enabled when the minor-mode is on.
> 
> I got the following warnings from the byte compiler:
> 
>   Warning: defface for ‘colour-tex-cruc’ fails to specify containing group
>   Warning: reference to free variable ‘crucible-supinf-enable’
>   Warning: reference to free variable ‘crucible-supinf-vshift’
>   Warning: reference to free variable ‘supinf-font-lock-cruc’
> 
> Style PO-lice:
> 
> > (defface colour-tex-cruc
> 
> US English is preferable, then it becomes consistent. The user
> shouldn't have think, "is the programmer a 'bloke' or
> a 'dude'?" ...
> 
> >   '( (default :inherit bold)
> >      ( ((class color) (min-colors 88) (background light))
> >        :foreground "#FF0000" )
> >      ( ((class color) (min-colors 88) (background dark))
> >        :foreground "#FF0000")
> >      (t :inherit font-lock-builtin-face) )
> >   "Typeface for tex keywords.")
> 
> Avoid hard-coding the same data (88 and "#FF0000") repeatedly.
> Normally, the method is to use `let'.
> 
> > (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)
> 
> `if' -> `while'
> 
> >            (member (car-safe (cdr prop)) crucible-supinf-vshift)
> >            (null (cddr prop)))
> >       (put-text-property beg next 'display nil))
> >       (setq beg next))))
> 
> This looks unorthodox but OK, I don't have a snappy answer
> what to do instead...
> 
> > (defun tex-typeface-crucible ()
> >   "Font-lock setup for mathematical symbols."
> >   (font-lock-flush (point-min) (point-max))
> 
> Is that the same as just (font-lock-flush) ?

The code is using narrow-to-region for finding areas where superior and
inferior typeface is enabled.

(defun crucible-supinf-match (limit)
  "Match superior and inferior glyph patterns up to LIMIT."
  (when (and crucible-mode
             (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))



 
> >   (if crucible-supinf-enable
> >       (progn
> >         (font-lock-add-keywords nil crucible-tex-keywords t)
> >         (font-lock-add-keywords nil supinf-font-lock-cruc t))
> >     (font-lock-remove-keywords nil crucible-tex-keywords)
> >     (supinf-disable-cruc (point-min) (point-max)))
> >   (font-lock-flush (point-min) (point-max)))
> 
> Is that the same as ... same.
> 
> -- 
> underground experts united
> http://user.it.uu.se/~embe8573
> https://dataswamp.org/~incal
> 
> 
>