logic variable

logic variable

(programming)A variable in a logic programming languagewhich is initially undefined ("unbound") but may get bound toa value or another logic variable during unification of thecontaining clause with the current goal. The value to whichit is bound may contain other variables which may themselvesbe bound or unbound.

For example, when unifying the clause

sad(X) :- computer(X, ibmpc).

with the goal

sad(billgates).

the variable X will become bound to the atom "billgates"yielding the new subgoal "computer(billgates, ibmpc)".