A struct of the following:
  {
    int         args;     <- number of arguments needed, can range from
                              0 to 6
    word_32    level1;    <-  Level 1 argument type
    word_32    level2;    <-  Level 1 argument type
    word_32    level3;    <-  Level 1 argument type
    word_32    level4;    <-  Level 1 argument type
    word_32    level5;    <-  Level 1 argument type
    word_32    level6;    <-  Level 1 argument type
  }
   
       Each 'leveln' is a hexadecimal digit representing an object type,
       as shown in the table below. Each entry in the table corresponds
       to a bit in the long. This is to accomidate USER RPL keywords, which
       can handle more than one type of argument, or SYSTEM RPL keywords
       which have their own DISPATCH methods.

       The following table shows the hex digit values for each
       argument type.  The column "# name" shows the object pointer
       name for the corresponding binary integer that may be used
       for a single argument function.

               Value   Bit   Argument           # name   User TYPE
               -----   ---   ----------------   ------   ---------
                 0      0     Any Object          any
                 1      1     Real Number         real         0
                 2      2     Complex Number      cmp          1
                 4      3     Character String    str          2
                 8      4     Array               arry       3,4
                10      5     List                list         5
                20      6     Global Name         idnt         6
                30      7     Local Name          lam          7
                80      8     Secondary           seco         8
               100      9     Symbolic            symb         9
               200     10     Symbolic Class      sym      6,7,9
               400     11     Hex String          hxs         10
               800     12     Graphics Object     grob        11
              1000     13     Tagged Object       TAGGED      12
              2000     14     Unit Object         unitob      13
              4000     15     ROM Pointer                     14
              8000     16     Binary Integer                  20
             10000     17     Directory                       15
             20000     18     Extended Real                   21
             40000     19     Extended Complex                22
             80000     20     Linked Array                    23
            100000     21     Character                       24
            200000     22     Code Object                     25
            400000     23     Library                         16
            800000     24     Backup                          17
           1000000     25     Library Data                    26
           2000000     26     External object1                27
           4000000     27     External object2                28
           8000000     28     External object3                29
          10000000     29     External object4                30