    <TT
CLASS="LITERAL"
>a</TT
> means implicitly in assignment
       to a target column, as well as explicitly.
       <TT
CLASS="LITERAL"
>i</TT
> means implicitly in expressions, as well as the
       other cases.
      </TD
></TR
><TR
><TD
><TT
CLASS="STRUCTFIELD"
>castmethod</TT
></TD
><TD
><TT
CLASS="TYPE"
>char</TT
></TD
><TD
>&nbsp;</TD
><TD
>       Indicates how the cast is performed.
       <TT
CLASS="LITERAL"
>f</TT
> means that the function specified in the <TT
CLASS="STRUCTFIELD"
>castfunc</TT