\gdlfunref{n-params}
\gdlfunref{keyword-set}
\gdlfunref{arg-present}
\gdlfunref{n-elements}
\gdlfunref{size}

\_EXTRA\index{\_EXTRA}
\_STRICT\_EXTRA\index{\_STRICT\_EXTRA}
\_REF\_EXTRA\index{\_REF\_EXTRA}

when by reference, when by value...

Keyword name abbreviations are allowed if unambiguous, e.g.:
\index{abbreviated keyword names}
\gdlcodeexample{arguments-abbr}{}{}
