Type Testing

Predicates

acyclic_term(?Term)

Succeeds if Term is acyclic (finite)

atom(?Atom)

Succeeds if Atom is a Prolog atom.

atomic(?Atomicterm)

Succeeds if Atomicterm is an atom, a number, or a string.

breal(?Breal)

Succeeds if Breal is a bounded real number.

compound(?Term)

Succeeds if Term is of type compound, i.e. a structure or a list.

current_atom(?Atom)

Succeeds if Atom is an atom in the system.

current_functor(?PredSpec)

Succeeds if PredSpec is a functor known to the system.

float(?Real)

Succeeds if Real is a floating point number.

free(?Var)

Succeeds if Var is a free variable, not a metaterm.

get_var_info(?Var, ?InfoName, ?Value)

Succeeds if Var is an uninstantiated variable, InfoName is a valid information name and the information value Value unifies with the value of the information.

ground(?Term)

Succeeds if Term is ground.

integer(?Integer)

Succeeds if Integer is an integer number.

is_event(?Term)

Succeeds if Term is an event name or handle

is_handle(?Term)

Succeeds if Term is an external data handle.

is_suspension(?Term)

Succeeds if Term is a sleeping suspension.

meta(?Var)

Succeeds if Var is a metaterm.

nonground(?VarTerm)

Succeeds if VarTerm is not ground.

nonground(?Term, -Variable)

Succeeds if Term is not a ground term and binds Variable to one of the variables inside Term.

nonground(+N, ?Term, ?VarList)

Succeeds if Term contains at least N different variables, and returns N of them in the list VarList.

nonvar(?Term)

Succeeds if Term is instantiated.

number(?Number)

Succeeds if Number is a number.

rational(?Rational)

Succeeds if Rational is a rational number.

real(?Real)

Succeeds if Real is a real (float or breal) number.

string(?String)

Succeeds if String is a string.

type_of(?Term, ?Type)

Succeeds if Type is the data type of the term Term.

var(?Var)

Succeeds if Var is a variable or a metaterm.