Boolean classes
The Boolean classes are True and False. Booleans are used in Smalltalk to implement both standard and application-defined control constructs. Although it might seem strange that Smalltalk does not provide any built-in mechanisms for controlling program running, this turns out not to be a limitation. Indeed, it adds a surprising degree of flexibility to the language.
Boolean messages
&, and:, eqv:, ifFalse:, ifFalse:ifTrue:, ifTrue:, ifTrue:ifFalse:, not, or:, |, xor:
Porting tip:
All Smalltalk dialects implement the same set of Boolean messages. Users should be aware that in some cases the compiler can optimize by in-lining control operations rather than implementing them as message sends. This in-lining is usually transparent unless there is an attempt to subclass or modify one of the Boolean classes.
Last modified date: 01/29/2015