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110 lines
4.5 KiB
XML
110 lines
4.5 KiB
XML
<?xml version="1.0" encoding="UTF-8" ?>
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<class name="bool" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="../class.xsd">
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<brief_description>
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A built-in boolean type.
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</brief_description>
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<description>
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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.
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Booleans can be directly used in [code]if[/code], and other conditional statements:
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[codeblocks]
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[gdscript]
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var can_shoot = true
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if can_shoot:
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launch_bullet()
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[/gdscript]
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[csharp]
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bool canShoot = true;
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if (canShoot)
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{
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LaunchBullet();
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}
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[/csharp]
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[/codeblocks]
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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].
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Booleans can be combined with the logical operators [code]and[/code], [code]or[/code], [code]not[/code] to create complex conditions:
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[codeblocks]
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[gdscript]
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if bullets > 0 and not is_reloading():
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launch_bullet()
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if bullets == 0 or is_reloading():
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play_clack_sound()
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[/gdscript]
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[csharp]
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if (bullets > 0 && !IsReloading())
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{
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LaunchBullet();
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}
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if (bullets == 0 || IsReloading())
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{
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PlayClackSound();
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}
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[/csharp]
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[/codeblocks]
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[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.
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[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.).
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</description>
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<tutorials>
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</tutorials>
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<constructors>
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<constructor name="bool">
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<return type="bool" />
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<description>
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Constructs a [bool] set to [code]false[/code].
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</description>
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</constructor>
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<constructor name="bool">
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<return type="bool" />
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<param index="0" name="from" type="bool" />
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<description>
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Constructs a [bool] as a copy of the given [bool].
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</description>
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</constructor>
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<constructor name="bool">
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<return type="bool" />
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<param index="0" name="from" type="float" />
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<description>
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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]).
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</description>
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</constructor>
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<constructor name="bool">
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<return type="bool" />
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<param index="0" name="from" type="int" />
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<description>
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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.
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</description>
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</constructor>
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</constructors>
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<operators>
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<operator name="operator !=">
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<return type="bool" />
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<param index="0" name="right" type="bool" />
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<description>
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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.
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</description>
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</operator>
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<operator name="operator <">
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<return type="bool" />
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<param index="0" name="right" type="bool" />
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<description>
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Returns [code]true[/code] if the left operand is [code]false[/code] and the right operand is [code]true[/code].
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</description>
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</operator>
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<operator name="operator ==">
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<return type="bool" />
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<param index="0" name="right" type="bool" />
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<description>
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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.
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</description>
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</operator>
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<operator name="operator >">
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<return type="bool" />
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<param index="0" name="right" type="bool" />
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<description>
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Returns [code]true[/code] if the left operand is [code]true[/code] and the right operand is [code]false[/code].
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</description>
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</operator>
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</operators>
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</class>
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