zr-tex8r

% upLaTeX文書
\documentclass[uplatex,a4paper]{jsarticle}
\usepackage{xparse}
\ExplSyntaxOn

\int_new:N \l_xx_total_int
\clist_new:N \l_xx_price_clist
\prop_new:N \l_xx_count_prop
\bool_new:N \l_xx_solved_bool
\int_new:N \l_xx_instid_int

zr-tex8r

\documentclass{article}
\makeatletter %!!!!!!!!!!!!!!!!!!!!!!!!! TeX code BEGIN
\newif\ifreview@ba@break
\def\review@ba@end{\review@ba@end@}
\DeclareRobustCommand{\reviewbreakall}[1]{%
  \begingroup
    \review@ba@breakfalse
    \review@break@all@a#1\review@ba@end
  \endgroup
}

wtsnjp

% plain TeX
\catcode`@=11
\def\x@cmd(#1){\edef\x@tmp{#1}\ifx\x@tmp\empty
  o\expandafter\x@cmd\else\x@fin #1\fi}\def\x@fin'#1'{#1}
\catcode`g=13\chardef\x@s=`g\defg{\char\x@s\x@cmd}
\catcode`@=12

% tests
\noindent
g('al')\break