godot/doc/classes/bool.xml

<?xml version="1.0" encoding="UTF-8" ?>
<class name="bool" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="../class.xsd">
	<brief_description>
		A built-in boolean type.
	</brief_description>
	<description>
		The [bool] is a built-in [Variant] type that may only store one of two values: [code]true[/code] or [code]false[/code]. You can imagine it as a switch that can be either turned on or off, or as a binary digit that can either be 1 or 0.
		Booleans can be directly used in [code]if[/code], and other conditional statements:
		[codeblocks]
		[gdscript]
		var can_shoot = true
		if can_shoot:
			launch_bullet()
		[/gdscript]
		[csharp]
		bool canShoot = true;
		if (canShoot)
		{
			LaunchBullet();
		}
		[/csharp]
		[/codeblocks]
		All comparison operators return booleans ([code]==[/code], [code]&gt;[/code], [code]&lt;=[/code], etc.). As such, it is not necessary to compare booleans themselves. You do not need to add [code]== true[/code] or [code]== false[/code].
		Booleans can be combined with the logical operators [code]and[/code], [code]or[/code], [code]not[/code] to create complex conditions:
		[codeblocks]
		[gdscript]
		if bullets &gt; 0 and not is_reloading():
			launch_bullet()

		if bullets == 0 or is_reloading():
			play_clack_sound()
		[/gdscript]
		[csharp]
		if (bullets &gt; 0 &amp;&amp; !IsReloading())
		{
			LaunchBullet();
		}

		if (bullets == 0 || IsReloading())
		{
			PlayClackSound();
		}
		[/csharp]
		[/codeblocks]
		[b]Note:[/b] In modern programming languages, logical operators are evaluated in order. All remaining conditions are skipped if their result would have no effect on the final value. This concept is known as [url=https://en.wikipedia.org/wiki/Short-circuit_evaluation]short-circuit evaluation[/url] and can be useful to avoid evaluating expensive conditions in some performance-critical cases.
		[b]Note:[/b] By convention, built-in methods and properties that return booleans are usually defined as yes-no questions, single adjectives, or similar ([method String.is_empty], [method Node.can_process], [member Camera2D.enabled], etc.).
	</description>
	<tutorials>
	</tutorials>
	<constructors>
		<constructor name="bool">
			<return type="bool" />
			<description>
				Constructs a [bool] set to [code]false[/code].
			</description>
		</constructor>
		<constructor name="bool">
			<return type="bool" />
			<param index="0" name="from" type="bool" />
			<description>
				Constructs a [bool] as a copy of the given [bool].
			</description>
		</constructor>
		<constructor name="bool">
			<return type="bool" />
			<param index="0" name="from" type="float" />
			<description>
				Cast a [float] value to a boolean value. Returns [code]false[/code] if [param from] is equal to [code]0.0[/code] (including [code]-0.0[/code]), and [code]true[/code] for all other values (including [constant @GDScript.INF] and [constant @GDScript.NAN]).
			</description>
		</constructor>
		<constructor name="bool">
			<return type="bool" />
			<param index="0" name="from" type="int" />
			<description>
				Cast an [int] value to a boolean value. Returns [code]false[/code] if [param from] is equal to [code]0[/code], and [code]true[/code] for all other values.
			</description>
		</constructor>
	</constructors>
	<operators>
		<operator name="operator !=">
			<return type="bool" />
			<param index="0" name="right" type="bool" />
			<description>
				Returns [code]true[/code] if the two booleans are not equal. That is, one is [code]true[/code] and the other is [code]false[/code]. This operation can be seen as a logical XOR.
			</description>
		</operator>
		<operator name="operator &lt;">
			<return type="bool" />
			<param index="0" name="right" type="bool" />
			<description>
				Returns [code]true[/code] if the left operand is [code]false[/code] and the right operand is [code]true[/code].
			</description>
		</operator>
		<operator name="operator ==">
			<return type="bool" />
			<param index="0" name="right" type="bool" />
			<description>
				Returns [code]true[/code] if the two booleans are equal. That is, both are [code]true[/code] or both are [code]false[/code]. This operation can be seen as a logical EQ or XNOR.
			</description>
		</operator>
		<operator name="operator &gt;">
			<return type="bool" />
			<param index="0" name="right" type="bool" />
			<description>
				Returns [code]true[/code] if the left operand is [code]true[/code] and the right operand is [code]false[/code].
			</description>
		</operator>
	</operators>
</class>