162: Mainline

Note that, whenever the receiver of an & message is false, the computation required to evaluate the argument is wasted, because the answer must be false no matter what the argument's value may be. Similarly, whenever the receiver of an | message is true, the computation required to evaluate the argument is wasted, because the answer must be true no matter what the argument's value may be.

To avoid wasting the computation required to evaluate arguments, many Smalltalk programmers avoid & and | altogether, using the and: and or: messages instead.