Constraint Logic Programming Using ECLiPSe

[eclipse 2]: X is 7, X is X+1.
No (0.00s cpu)
[eclipse 3]: X is X+1, X is 7.
instantiation fault in +(X, 1, X)
Abort
[eclipse 4]: X is 3, Y is X+1.
Y = 4
X = 3
Yes (0.00s cpu)
[eclipse 5]: Y is X+1, X is 3.
instantiation fault in +(X, 1, Y)
Abort
Solutions to selected exercises 307
Exercise 3.2
[eclipse 1]: Z is 2, q(X).
Z = 2
X = X
Yes (0.00s cpu)
[eclipse 2]: Z is 2, q(Z).
Z = 2
Yes (0.00s cpu)
[eclipse 3]: Z is 2, q(X), Y is Z+1.
Z = 2
X = X
Y = 3
Yes (0.00s cpu)
[eclipse 4]: Z = 2, inc(X), X = 2.
instantiation fault in +(X, 1, Z) in module eclipse
Abort
[eclipse 5]: X = 2, inc(X), Z = 2.
X = 2
Z = 2
Yes (0.00s cpu)
Exercise 3.3
An example is the query min(1+1, 3, Z). For the first program it yields the
answer Z = 1+1 and for the second program the answer Z = 2.
Exercise 3.4
Assume the declarations
:- op(500, yfx, have).
:- op(400, yfx, and).