Type Testing Built-ins

The following built-ins provide type testing in ECLiPSe .

ECLiPSe Type Testing built-in.

atom(?Atom)

Succeeds if Atom is a Prolog atom.  

atomic(?Atomicterm)

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

compound(?Term)

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

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.  

integer(?Integer)

Succeeds if Integer is an integer number.  

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.  

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 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.