%%% ====================================================================
%%%  @LaTeX-file{
%%%     filename        = "amsxtra.dtx",
%%%     version         = "1.2b",
%%%     date            = "1996/10/28",
%%%     time            = "14:54:44 EST",
%%%     author          = "American Mathematical Society",
%%%     copyright       = "Copyright (C) 1996 American Mathematical Society,
%%%                        all rights reserved.  Copying of this file is
%%%                        authorized only if either:
%%%                        (1) you make absolutely no changes to your copy,
%%%                        including name; OR
%%%                        (2) if you do make changes, you first rename it
%%%                        to some other name.",
%%%     address         = "American Mathematical Society,
%%%                        Technical Support,
%%%                        Electronic Products and Services,
%%%                        P. O. Box 6248,
%%%                        Providence, RI 02940,
%%%                        USA",
%%%     telephone       = "401-455-4080 or (in the USA and Canada)
%%%                        800-321-4AMS (321-4267)",
%%%     FAX             = "401-331-3842",
%%%     checksum        = "05092 135 536 5380",
%%%     email           = "tech-support@ams.org (Internet)",
%%%     codetable       = "ISO/ASCII",
%%%     keywords        = "latex, amslatex, ams-latex",
%%%     supported       = "yes",
%%%     abstract        = "This is part of the AMS-\LaTeX{} distribution.
%%%                        It contains some rarely used user-level commands",
%%%     docstring       = "The checksum field above contains a CRC-16
%%%                        checksum as the first value, followed by the
%%%                        equivalent of the standard UNIX wc (word
%%%                        count) utility output of lines, words, and
%%%                        characters.  This is produced by Robert
%%%                        Solovay's checksum utility.",
%%%  }
%%% ====================================================================
%\iffalse
%<*driver>
\documentclass{amsdtx}
\begin{document}
\title{The \pkg{amsxtra} package}
\author{American Mathematical Society\\Michael Downes}
\date{28 October 1996 \\
Version 1.02}
\hDocInput{amsxtra.dtx}
\end{document}
%</driver>
%\fi
%
% \maketitle
%
% \MakeShortVerb\|
%
% \section{Introduction}
%    The \pkg{amsxtra} package contains a few rarely used commands that
%    were present in version 1.1 of the \pkg{amstex} package:
%    \cn{fracwithdelims}, {accentedsymbol}, \cn{sphat}, \cn{spcheck},
%    \cn{sptilde}, \cn{spdot}, \cn{spddot}, \cn{spdddot}, \cn{spbreve}.
%    If any of these commands were used in existing documents, the
%    \pkg{amsxtra} package provides a way to get them. But for 99\% of
%    documents using the \pkg{amstex} package these commands are just
%    wasted overhead.
%
% \StopEventually{}
%
%    \begin{macrocode}
\ProvidesPackage{amsxtra}[1996/10/28 v1.2b]
%    \end{macrocode}
%    We need to ensure that either the \pkg{amstex} package or the
%    \pkg{amsmath} package is loaded. This means we need something a
%    little more complicated than \cn{RequirePackage}.
%    \begin{macrocode}
\@ifpackageloaded{amstex}{}{%
  \RequirePackage{amsmath}[1996/10/01 v1.2]}
%    \end{macrocode}
%
%    Superscripted accent characters.
%    \begin{macrocode}
\def\sphat{^{\mathchoice{}{}%
 {\,\,\smash[b]{\hbox{\lower4\ex@\hbox{$\m@th\widehat{\null}$}}}}%
 {\,\smash[b]{\hbox{\lower3\ex@\hbox{$\m@th\hat{\null}$}}}}}}
\def\spcheck{^\vee}
\def\sptilde{^\sim}
\def\spdot{^{\hbox{\raise\ex@\hbox{\normalfont .}}}}
\def\spddot{^{\hbox{\raise\ex@\hbox{\normalfont ..}}}}
\def\spdddot{^{\hbox{\raise\ex@\hbox{\normalfont...}}}}
\def\spbreve{^{\!\smash[b]{\hbox{\lower4\ex@\hbox{\u{}}}}}}
%    \end{macrocode}
%
%    The \cn{fracwithdelims} command is skipped if the base package is
%    \pkg{amsmath}; it is only needed if the base package is
%    \pkg{amstex}.
%    \begin{macrocode}
\@ifpackageloaded{amstex}{%
\def\fracwithdelims#1#2{\new@ifnextchar[{\fracwithdelims@#1#2}%
  {\fracwithdelims@#1#2[\@empty]}}
\def\fracwithdelims@#1#2[#3]#4#5{\relax
  \ifx\@empty#3{#4\overwithdelims#1#2#5}\else
  {#4\abovewithdelims#1#2#3\relax#5}\fi}
}{}
%    \end{macrocode}
%
%    Perhaps |\accentedsymbol| should use |\newsavebox|, but I don't
%    know of any compelling reason at the moment.[mjd,5-Sep-1994]
%    |\accentedsymbol| can only produce a single size of
%    the given symbol, so you'd need two different versions for main
%    size and subscript size.
%    \begin{macrocode}
\def\accentedsymbol#1#2{\expandafter\newbox\csname\expandafter
  \@gobble\string#1@box\endcsname
 \expandafter\setbox\csname\expandafter\@gobble
   \string#1@box\endcsname\hbox{$\m@th#2$}%
  \newcommand{#1}{%
    \expandafter\copy\csname\expandafter\@gobble\string#1@box
    \endcsname{}}%
}
%    \end{macrocode}
%
%    Change the definition of \qc{\~} to automatically remove a
%    preceding space as well as a following space, if present.
%    \begin{macrocode}
\def~{\nobreakspace}
\DeclareRobustCommand{\nobreakspace}{\unskip\nobreak\ \ignorespaces}
%    \end{macrocode}
%
%    The usual \cs{endinput} to ensure that random garbage at the end of
%    the file doesn't get copied by \fn{docstrip}.
%    \begin{macrocode}
\endinput
%    \end{macrocode}
%
% \CheckSum{113}
% \Finale