IMP Core Environment Standard


                       Section 11: Miscellaneous




*       constant name NIL

           The predefined pointer NIL may be used to terminate linked
        lists of items; any pointer variable which is pointing to NIL
        will have all its bits clear (0) {IAY: better wording required
        here, but see language implications section}.


*       integer function SIZE OF ( name X )

           The number of storage units occupied by the given variable is
        returned.  The unit is machine dependent but is commonly a byte.


*       integer function TYPE OF ( name X )

           This function returns a code which indicates the type of the
        object supplied as parameter.  The complete list of code values
        which may be returned by TYPE OF is as follows:

         0 - unknown type
         1 - integer
         2 - real
         3 - string
         4 - record
         5 - byte integer
         6 - short integer
         7 - long integer
         8 - long real
         9 - array
        10 - label