amstex

<..equations of amstex.tex..>+
 \let\:tempc=\frac
 \pend:defII\:temp{\a:frac}
 \append:defII\:temp{\b:frac}
 \HLet\frac=\:temp
 \NewConfigure{frac}{2}
 \let\:tempc=\dfrac
 \pend:defII\:temp{\a:dfrac}
 \append:defII\:temp{\b:dfrac}
 \HLet\dfrac=\:temp
 \NewConfigure{dfrac}{2}
 \let\:tempc=\tfrac
 \pend:defII\:temp{\a:tfrac}
 \append:defII\:temp{\b:tfrac}
 \HLet\tfrac=\:temp
 \NewConfigure{tfrac}{2}
 \let\:tempc=\binom
 \pend:defII\:temp{\a:binom}
 \append:defII\:temp{\b:binom}
 \HLet\binom=\:temp
 \NewConfigure{binom}{2}
 \let\:tempc=\dbinom
 \pend:defII\:temp{\a:dbinom}
 \append:defII\:temp{\b:dbinom}
 \HLet\dbinom=\:temp
 \NewConfigure{dbinom}{2}
 \let\:tempc=\tbinom
 \pend:defII\:temp{\a:tbinom}
 \append:defII\:temp{\b:tbinom}
 \HLet\tbinom=\:temp
 \NewConfigure{tbinom}{2}
 \let\:temp=\boxed
 \pend:defI\:temp{\a:boxed}
 \append:defI\:temp{\b:boxed}
 \HLet\boxed=\:temp
 \NewConfigure{boxed}{2}
 -_-_-