WHATIS(something) has a value depending on what it is:

        A number        0                             bit
        Not a number:   1                              0
                a macro:              set 02 bit       1
                a variable:           set 04 bit       2
                a vector:             set 010 bit      3
                     a float vector:  set 040 bit      5
                     a string vector: set 0100 bit     6
                a keyword:            set 020 bit      4

So if "aa" is the name of a string vector, WHATIS(aa) has the value 0111, or
73, whereas WHATIS(HELP) has the value 021, or 17. WHATIS(1) is 0.

There is a macro is_set in utils that tests if a particular bit is
set by WHATIS, for example
	if(is_set(kkk,1) == 1) { echo kkk is a macro }
tests bit 1 (macro) for "kkk" and prints its findings;
	if(is_macro(kkk)) { echo kkk is a macro }
also works.