Term test

• atom(X) X is currently instantiated to an atom.

• atomic(X) X is currently instantiated to an atom or a number.

• float(X) X is currently instantiated to a float.

• real(X) The same as float(X).

• integer(X) X is currently instantiated to an integer.

• number(X) X is currently instantiated to a number.

• nonvar(X) X is a non-variable.

• var(X) X is currently uninstantiated.

• compound(X) X is a compound term. It is true if X is either a structure or a list.

• ground(X) X is ground.