[elpa] externals/auctex 513490f 22/78: Implement multi-level script fontification

[Tassilo Horn]

branch: externals/auctex
commit 513490f7b15fbc4676c706e3968eba9768d0194c
Author: Tassilo Horn <address@hidden>
Commit: Tassilo Horn <address@hidden>

    Implement multi-level script fontification
    
    * font-latex.el (font-latex-fontify-script): Add possible value
    `multi-level' to allow raising/lowering scripts of scripts.
    (font-latex-match-script): Use it.
---
 ChangeLog     |    4 ++++
 font-latex.el |   29 +++++++++++++++++++++--------
 2 files changed, 25 insertions(+), 8 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index d57cf18..3d698b7 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,9 @@
 2015-09-03  Tassilo Horn  <address@hidden>
 
+       * font-latex.el (font-latex-fontify-script): Add possible value
+       `multi-level' to allow raising/lowering scripts of scripts.
+       (font-latex-match-script): Use it.
+
        * tex.el (TeX-tex-mode): Don't ignore case when matching the
        TeX-format-list regexes.
        (TeX-expand-list): Add expansion of %(PDFout) to -output-format
diff --git a/font-latex.el b/font-latex.el
index 18c0866..2a9fc26 100644
--- a/font-latex.el
+++ b/font-latex.el
@@ -851,10 +851,22 @@ locking machinery will be triggered."
 
 (defcustom font-latex-fontify-script (not (featurep 'xemacs))
   "If non-nil, fontify subscript and superscript strings.
-This feature does not work in XEmacs."
-  :type 'boolean
+This feature does not work in XEmacs.
+
+By default, super/subscripts are raised/lowered if this variable
+is non-nil.  This fontification only affects one level of
+scripts, e.g., in x^y^z, the y and the z have the same size and
+are equally raised over x.  If this variable is set to the symbol
+`multi-level', then y is raised above x, and z is raised above y.
+With many script levels, the text might become too small to be
+readable."
+  :type '(choice (boolean :tag "Enabled")
+                (const :tag "Multiple levels" multi-level))
   :group 'font-latex)
-(put 'font-latex-fontify-script 'safe-local-variable 'TeX-booleanp)
+(put 'font-latex-fontify-script 'safe-local-variable
+     (lambda (val)
+       (or (TeX-booleanp val)
+          (eq 'multi-level val))))
 
 (defcustom font-latex-script-display '((raise -0.3) . (raise 0.3))
   "Display specification for subscript and superscript content.
@@ -1852,11 +1864,12 @@ END marks boundaries for searching for quotation ends."
   (when (and font-latex-fontify-script
             (re-search-forward "[_^] *\\([^\n\\{}]\\|\
 \\\\\\(address@hidden|[^ \t\n]\\)\\|\\({\\)\\)" limit t))
-    (if (font-latex-faces-present-p '(font-latex-subscript-face
-                                     font-latex-superscript-face))
-       ;; Apply subscript and superscript highlighting only once in
-       ;; order to prevent the font size becoming too small.  We set
-       ;; an empty match to do that.
+    (if (and (not (eq 'multi-level font-latex-fontify-script))
+            (font-latex-faces-present-p '(font-latex-subscript-face
+                                          font-latex-superscript-face)))
+       ;; Apply subscript and superscript highlighting only once (in case
+       ;; font-latex-fontify-script is not 'multi-level) in order to prevent
+       ;; the font size becoming too small.  We set an empty match to do that.
        (let ((point (point)))
          (store-match-data (list point point point point)))
       (when (match-end 3)