Re: Separating colour and positioning functioning

[Emanuel Berg via Users list for the GNU Emacs text editor <help-gnu-emacs@gnu.org>]

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) ?

>   (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.

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