%
% $Id: underscore.sty,v 1.1 1994/01/03 04:45:29 qjb Exp $
% $Source: /home/qjb/tex/macros/RCS/underscore.sty,v $
% $Author: qjb $
%
% This .sty file can be input by plain TeX or LaTeX.  It allows
% the underscore character to be used outside of math mode as a
% normal underscore character and inside math mode as a
% subscript character.  Although the TeXbook considers the
% default treatment of the underscore character as an error
% outside of math mode for checking, the frequency with which
% the underscore character is needed in technical writing about
% computer subjects makes this a pain to deal with.
% 
\catcode`\_=\active
\def\@underscore{\ifmmode\sb\else\_\fi}
\let_=\@underscore