displaying subscripts and superscripts

displaying subscripts and superscripts

[Mirko]

Hello,

I am trying to display text following an underscore as a subscript and
following a caret as a superscript.  By looking at various pieces of
code (tex-mode.el  and pretty-greek.el from Pascal Bourgignon), I came
up with the following (which, of course does not work):

(defvar suscript-height-minimum 0)
(defvar suscript-height-ratio 0.8)

(defun suscript-height (height)
  "Return the integer height of subscript/superscript font in 1/10
points.
Not smaller than the value set by `tex-suscript-height-minimum'."
  (ceiling (max (if (integerp suscript-height-minimum)
		    suscript-height-minimum
		    ;; For bootstrapping.
		    (condition-case nil
			(* suscript-height-minimum
			   (face-attribute 'default :height))
		      (error 0)))
		;; NB assumes height is integer.
		(* height suscript-height-ratio))))

(defface superscript
  '((t :height suscript-height))
  "Face used for superscripts.")

(defface subscript
  '((t :height suscript-height))
  "Face used for subscripts.")

(defun suscript-match-regexp (escape-char)
  "regexp for suscripted text match in common-lisp code"
  (let ((terminating-string (format "_^ 	)$-")))
    (format "%s\\(.*?\\)[%s]" escape-char
	    terminating-string terminating-string)))

(defvar subscript-match (suscript-match-regexp "_")
  "Matches _whatever[_|^|SPACE|TAB|)")
(defvar superscript-match (suscript-match-regexp "\\^")
  "Matches ^whatever[_|^|SPACE|TAB|)")

(defun pretty-suscript ()
  "Load super&subscript keywords into `suscript-flk' and
load that into `font-lock-keywords'"
  (interactive)
  (setq suscript-flk
	`((,subscript-match
	   (1 (face subscript display (raise 0.2))))
	  (,superscript-match
	   (1 (face superscript display (raise -0.2))))))
  (font-lock-add-keywords nil suscript-flk))

(defun cancel-pretty-suscript ()
  "Remove `suscript-flk' keywords from `font-lock-keywords'"
  (interactive)
  (font-lock-remove-keywords nil suscript-flk))

The contents `font-lock-keywords' are as follows:

(t
 (("_\\(.*?\\)[_^ 	)$-]"
   (1
    (face subscript display
	  (raise 0.2))))
  ("\\^\\(.*?\\)[_^ 	)$-]"
   (1
    (face superscript display
	  (raise -0.2))))
 ...)

To my untrained eyes, it looks OK, when compared to entries produced
by pretty-greek.el

So, where am I going wrong?  (Hopefully the list is finite).

Thank you,

Mirko

Re: displaying subscripts and superscripts

[Stefan Monnier]

> (defun suscript-height (height)
[...]
> (defface superscript
>   '((t :height suscript-height))
>   "Face used for superscripts.")

The :height attribute cannot be a function.  You probably just want to
use 0.8 (or suscript-height-ratio) here instead.


        Stefan

Re: displaying subscripts and superscripts

[Glenn Morris]

Stefan Monnier wrote:

>> (defun suscript-height (height)
> [...]
>> (defface superscript
>>   '((t :height suscript-height))
>>   "Face used for superscripts.")
>
> The :height attribute cannot be a function. 

Err, tex-mode.el uses a function for :height, and it seems to work...

The elisp manual says :height can be a function.

Re: displaying subscripts and superscripts

[Stefan Monnier]

>>> (defun suscript-height (height)
>> [...]
>>> (defface superscript
>>> '((t :height suscript-height))
>>> "Face used for superscripts.")
>> The :height attribute cannot be a function. 
> Err, tex-mode.el uses a function for :height, and it seems to work...
> The elisp manual says :height can be a function.

Huh!?  Indeed!


        Stefan "This tex-suscript-height is really overkill, BTW"

Re: displaying subscripts and superscripts

[Mirko]

On Apr 18, 11:19 pm, Stefan Monnier <monn...@iro.umontreal.ca> wrote:
> > (defun suscript-height (height)
> [...]
> > (defface superscript
> >   '((t :height suscript-height))
> >   "Face used for superscripts.")
>
> The :height attribute cannot be a function.  You probably just want to
> use 0.8 (or suscript-height-ratio) here instead.
>
>         Stefan

Well, I tried that, and that did not work.  But one more thing may be
amiss.  In tex-mode.el, the subscript is defined as belonging to the
`tex group.

(defface subscript
  '((t :height tex-suscript-height)) ;; :raise -0.2
  "Face used for subscripts."
  :group 'tex)

I will look into that next.

Thanks,

Mirko