spanning super and sub scripts \<^bsub> .. \<^esub> and \<^bsup> .. \<^esup>

--- a/lib/texinputs/isabelle.sty	Sat Dec 27 21:02:14 2003 +0100
+++ b/lib/texinputs/isabelle.sty	Mon Dec 29 06:07:44 2003 +0100
@@ -28,6 +28,14 @@
 \newcommand{\isactrlisup}[1]{\emph{\isascriptstyle${}\sp{#1}$}}
 \newcommand{\isactrlbold}[1]{{\bfseries\upshape\boldmath#1}}
 
+% somewhat hackish: spanning sub/super scripts (\<^bsub>..\<^esub>)
+\newcommand{\isactrlbsub}{%
+\def\isatext##1{\isastylescript##1}\begin{math}_\bgroup}
+\newcommand{\isactrlesub}{\egroup\end{math}}
+\newcommand{\isactrlbsup}{%
+\def\isatext##1{\isastylescript##1}\begin{math}^\bgroup}
+\newcommand{\isactrlesup}{\egroup\end{math}}
+
 \newdimen\isa@parindent\newdimen\isa@parskip
 
 \newenvironment{isabellebody}{%