Boolean values

Boolean values
You are encouraged to solve this task according to the task description, using any language you may know.

Show how to represent the boolean states "true" and "false" in a language. If other objects represent "true" or "false" in conditionals, note it.

BASIC

Works with: QuickBasic version 4.5

QuickBasic has no keywords for true and false. Boolean expressions evaluate to 0 when false, and a non-zero value when true. Numbers also work in place of boolean expressions following those rules.

Java

Java has true and false keywords, representing the only values of type boolean. There are also object wrappers Boolean.TRUE and Boolean.FALSE, of type Boolean which may be un-boxed into booleans (auto-unboxed in Java 1.5+). There are no automatic conversions from any other types into boolean, and it is a compile-time error to use any type other than boolean or Boolean in a place that expects a boolean (e.g. if-statement condition, while-statement condition, operand of a logical operator, etc.).

Perl

The values in Perl that are false are: the number 0 (as a number, or as the string '0'), the empty string , the empty list (), and undef.

Everything else is true.

Perl has no special "true" or "false" keywords.

Python

The values in Python that are false are: False, None, 0 (including 0 of all numeric types, and any object whose .__nonzero__() method returns false), and empty containers (including empty strings, lists, tuples, dictionaries, sets, etc., and any object whose .__len__() method returns 0).

Everything else is true. Constant True exists.

Ruby

The only values in Ruby that are false are: false and nil. They have synonyms FALSE and NIL.

Everything else (including the number 0 and the empty string) is true. Constants true (and TRUE) exist.

false, nil and true are singleton instances of classes FalseClass, NilClass and TrueClass respectively.