@ ARGUMENTS

        [SIC\]@ Macro_Name [Arg1 [Arg2 [...]]]

    The arguments passed to the macro are described by the structure PRO%:
        - PRO%NAME: calling procedure name,
        - PRO%NARG: number of arguments passed,
        - PRO%ARG: a character array (size PRO%NARG) providing all the
          arguments. This array is not defined if PRO%NARG is 0.
    The  structure  is updated when entering each macro. Up to 32 parameters
    can be given.

    Note that the arguments are all saved as character  strings.  A  typical
    use is:
        SIC> LET MYVAR 'PRO%ARG[1]'
    to  substitute  the character string by its content. See also HELP PARSE
    for advanced argument parsing.

    The old-fashion way to access the arguments is to use the tokens &1, &2,
    ..., &9. They are substituted to the corresponding arguments as they are
    found in the body of the procedure, even within character  strings.  For
    example
        SIC> say "a&1b"
    will  display  the  first argument value surrounded by "a" and "b". Note
    that these tokens can be used to access the 9 first arguments only.