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.