markup.sty

\usepackage{zref-abspos}
\newcommand*{\SEP}[1]{

  \zsaveposy{#1}

}

\newcommand\config[2]{
  \SEP{config=#1=#2}
}

\ifdefined\qunlist
\let\oldqunlist\qunlist
\let\oldendqunlist\endqunlist
\renewenvironment{qunlist}{
  \SEP{begin_questions}
  \oldqunlist
  \let\oldqns\qns
  \renewcommand\qns{\SEP{new_question}\oldqns}
  \newcommand\qpart{\SEP{new_part}}
}
{
  \oldendqunlist
  \SEP{end_questions}
}
\fi

\newenvironment{Choices}{
  \SEP{begin_choices}
  \newcommand{\TrueChoice}{\SEP{true_choice}}
  \newcommand{\FalseChoice}{\SEP{false_choice}}
  \newcommand{\Hint}{\SEP{hint}}
}{
  \SEP{end_choices}
}

\newenvironment{Multi}{
  \SEP{begin_multi}
  \newcommand{\TrueChoice}{\SEP{true_choice}}
  \newcommand{\FalseChoice}{\SEP{false_choice}}
  \newcommand{\Hint}{\SEP{hint}}
}{
  \SEP{end_multi}
}

\newenvironment{Freeform}[1]{
  \SEP{begin_freeform}
  \SEP{ans_equals@#1}
  \newcommand{\Hint}{\SEP{hint}}
}{
  \SEP{end_freeform}
}

\let\olddocument\document
\renewcommand\document{\olddocument\SEP{begin_document}}

\let\oldenddocument\enddocument
\renewcommand\enddocument{\SEP{end_document}\oldenddocument}