LaTeX Hook management

internal hook commands

Some internal hook commands defined in LaTeX2e, for example the \g@addto@macro macro:

\long\def\g@addto@macro#1#2{%
  \begingroup
    \toks@\expandafter{#1#2}%
    \xdef#1{\the\toks@}%
  \endgroup}

Hook Managemant

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