"""Short-circuit boolean operators and evaluation order.""" from timer import test, dead @test def test_and_both_sides(t): # True and X — both operands evaluated, result is X x = (True @ t[0] and 42 @ t[1, dead(2)]) @ t[dead(1), 2] @test def test_and_short_circuit(t): # False and ... — right side never evaluated x = (False @ t[0] and True @ t[dead(1)]) @ t[1, dead(2)] @test def test_or_short_circuit(t): # True or ... — right side never evaluated x = (True @ t[0] or False @ t[dead(1)]) @ t[1, dead(2)] @test def test_or_both_sides(t): # False or X — both operands evaluated, result is X x = (False @ t[0] or 42 @ t[1, dead(2)]) @ t[dead(1), 2] @test def test_not(t): # not evaluates its operand, then negates x = (not True @ t[0]) @ t[1] y = (not False @ t[2]) @ t[3] @test def test_chained_and(t): # 1 and 2 and 3 — all truthy, all evaluated left-to-right x = (1 @ t[0] and 2 @ t[1, dead(3)] and 3 @ t[2, dead(3)]) @ t[dead(1), dead(2), 3] @test def test_chained_or(t): # 0 or "" or 42 — first two falsy, all evaluated until truthy found x = (0 @ t[0] or "" @ t[1, dead(3)] or 42 @ t[2, dead(3)]) @ t[dead(1), dead(2), 3] @test def test_mixed_and_or(t): # True and False or 42 => (True and False) or 42 => False or 42 => 42 x = ((True @ t[0] and False @ t[1, dead(2)]) @ t[dead(1), 2, dead(4)] or 42 @ t[3, dead(4)]) @ t[dead(2), dead(3), 4] @test def test_and_side_effects(t): # Both functions called when left side is truthy def f(): return 10 @ t[1] def g(): return 20 @ t[4] x = ((f @ t[0])() @ t[2] and (g @ t[3])() @ t[5]) @ t[6] @test def test_or_side_effects(t): # Both functions called when left side is falsy def f(): return 0 @ t[1] def g(): return 20 @ t[4] x = ((f @ t[0])() @ t[2] or (g @ t[3])() @ t[5]) @ t[6]