Re: tex mode sub- and super-scripts

[Reiner Steib]

[ I'd suggest to move this discussion to <emacs-devel@gnu.org>.

  Summary: In Emacs TeX-mode (textmodes/tex-mode.el), there's no
  option to suppress the raise/lowering of superscripts and
  subscripts.  In AUCTeX, we used tex-mode.el's code, but added
  options to turn off this feature.

  %%%%%%%%%%
  $a_0 = a_{f}^{2} + b_{\alpha}$
  \bye
  %%%%%%%%%%
]

On Sun, Jul 01 2007, Eli Zaretskii wrote:

>> Date: Sat, 30 Jun 2007 21:02:56 -0500 (CDT)
>> From: Mark Alford <alford@wuphys.wustl.edu>
>> 
>> Eli Zaretskii <eliz@gnu.org> wrote:
>> > You should be able to customize the two faces `subscript' and
>> > `superscript' defined by tex-mode.
>> 
>> I can control their size but not their raising/lowering.
[...]
> It seems to be explicit code, see tex-font-lock-suscript.  [...]
>
> I suggest to submit a bug report asking for this feature to be
> customizable.

I'd be willing to port AUCTeX's customization options ([1], code
written by me) to tex-mode.el.  Any objections?  Stefan?

(If it's okay to install this patch, should it go to the Emacs 22
branch?)

--8<---------------cut here---------------start------------->8---
--- tex-mode.el 20 May 2007 15:18:56 +0200      1.186
+++ tex-mode.el 01 Jul 2007 10:38:31 +0200      
@@ -243,6 +243,21 @@
   :options '("''" "\">" "\"'" ">>" "»")
   :group 'tex)
 
+(defcustom tex-fontify-script t
+  "If non-nil, fontify subscript and superscript strings."
+  :type 'boolean
+  :group 'tex)
+(put 'tex-fontify-script 'safe-local-variable 'booleanp)
+
+(defcustom tex-font-script-display '((raise -0.3) . (raise 0.3))
+  "Display specification for subscript and superscript content.
+The car is used for subscript, the cdr is used for superscripts."
+  :group 'tex
+  :type '(cons (choice (sexp :tag "Subscript form")
+                      (const :tag "No lowering" nil))
+              (choice (sexp :tag "Superscript form")
+                      (const :tag "No raising" nil))))
+
 (defvar tex-last-temp-file nil
   "Latest temporary file generated by \\[tex-region] and \\[tex-buffer].
 Deleted when the \\[tex-region] or \\[tex-buffer] is next run, or when the
@@ -593,13 +608,14 @@
                  (setq pos (1- pos) odd (not odd)))
                odd))
     (if (eq (char-after pos) ?_)
-       '(face subscript display (raise -0.3))
-      '(face superscript display (raise +0.3)))))
+       '(face subscript display (car tex-font-script-display))
+      '(face superscript display (cdr tex-font-script-display)))))
 
 (defun tex-font-lock-match-suscript (limit)
   "Match subscript and superscript patterns up to LIMIT."
-  (when (re-search-forward "[_^] *\\([^\n\\{}]\\|\
-\\\\\\([a-zA-Z@]+\\|[^ \t\n]\\)\\|\\({\\)\\)" limit t)
+  (when (and tex-fontify-script
+            (re-search-forward "[_^] *\\([^\n\\{}]\\|\
+\\\\\\([a-zA-Z@]+\\|[^ \t\n]\\)\\|\\({\\)\\)" limit t))
     (when (match-end 3)
       (let ((beg (match-beginning 3))
            (end (save-restriction
--8<---------------cut here---------------end--------------->8---

Bye, Reiner.

[1] Cf.
    http://mid.gmane.org/v93b09938i.fsf%40marauder.physik.uni-ulm.de
    http://mid.gmane.org/v9hcop79f3.fsf%40marauder.physik.uni-ulm.de

,----[ <f1> v font-latex-fontify-script RET ]
| font-latex-fontify-script is a variable defined in `font-latex'.
| Its value is t
| 
| This variable is safe as a file local variable if its value
| satisfies the predicate `TeX-booleanp'.
| 
| Documentation:
| If non-nil, fontify subscript and superscript strings.
| This feature does not work in XEmacs.
| 
| You can customize this variable.
`----

,----[ M-x customize-variable RET font-latex-script-display RET ]
| Font Latex Script Display: [Hide Value]
| Choice: [Value Menu] Subscript form: (raise -0.3)
| Choice: [Value Menu] Superscript form: (raise 0.3)
|    [State]: STANDARD.
| 
| Display specification for subscript and superscript content. [Hide Rest]
| The car is used for subscript, the cdr is used for superscripts.
| Parent groups: [Font Latex]
`----

,----[ M-x customize-variable RET font-latex-script-display RET ]
| font-latex-script-display: [Hide Value]
| Choice: [Value Menu] No lowering
| Choice: [Value Menu] No raising
|    [State]: SET for current session only.
`----
-- 
       ,,,
      (o o)
---ooO-(_)-Ooo---  |  PGP key available  |  http://rsteib.home.pages.de/