ked whenever Tcl does
        not recognize an invoked procedure name.  <SPAN
CLASS="APPLICATION"
>PL/Tcl</SPAN
>'s standard version
        of this procedure tries to find a module in <TT
CLASS="LITERAL"
>pltcl_modules</TT
>
        that will define the required procedure.  If one is found, it is
        loaded into the interpreter, and then execution is allowed to
        proceed with the originally attempted procedure call.  A
        secondary table <TT
CLASS="LITERAL"
>pltcl_modfuncs</TT
> provides an 