3.4 Verify Type of a Term

var(+Term)

Succeeds if Term currently is a free variable.

nonvar(+Term)

Succeeds if Term currently is not a free variable.

integer(+Term)

Succeeds if Term is bound to an integer.

float(+Term)

Succeeds if Term is bound to a floating point number.

number(+Term)

Succeeds if Term is bound to an integer or a floating point number.

atom(+Term)

Succeeds if Term is bound to an atom.

string(+Term)

Succeeds if Term is bound to a string.

atomic(+Term)

Succeeds if Term is bound to an atom, string, integer or floating point number.

compound(+Term)

Succeeds if Term is bound to a compound term. See also functor/3 and =../2.

ground(+Term)

Succeeds if Term holds no free variables.