#### 4.4.2 boolean [Type] ¶

#### Supertypes:: ¶

boolean, symbol, t

#### Description:: ¶

The type boolean contains the symbols t and nil, which represent true and false, respectively.

#### See Also:: ¶

t (constant variable), nil (constant variable), if [Special Operator] , not [Function] , complement [Function]

#### Notes:: ¶

Conditional operations, such as if, permit the use of generalized booleans, not just booleans; any non-nil value, not just t, counts as true for a generalized boolean. However, as a matter of convention, the symbol t is considered the canonical value to use even for a generalized boolean when no better choice presents itself.