Is an enumeration constant (a read-only LIST, see Lists)
containing the numerical values of the various classes of ANA variables.
Members: SCALAR, STRING, RANGE, ARRAY,
TRANSFER, ASSOC, FUNC_PTR, SCAL_PTR,
SUBSC_PTR, FILEMAP, CLIST, LIST,
KEYWORD, LIST_PTR, CPLIST, SUBROUTINE,
FUNCTION, BLOCKROUTINE, EVB, FIXED_NUMBER,
UNDEFINED.
See also: Data Classes, #TYPE