mirror of
https://github.com/godotengine/godot.git
synced 2024-12-15 10:12:40 +08:00
110 lines
4.5 KiB
XML
110 lines
4.5 KiB
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]>[/code], [code]<=[/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 > 0 and not is_reloading():
|
|
launch_bullet()
|
|
|
|
if bullets == 0 or is_reloading():
|
|
play_clack_sound()
|
|
[/gdscript]
|
|
[csharp]
|
|
if (bullets > 0 && !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 <">
|
|
<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 >">
|
|
<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>
|