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Overhaul bool documentation #80141

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Aug 3, 2023
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Overhaul bool documentation #80141

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36 changes: 20 additions & 16 deletions doc/classes/bool.xml
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Original file line number Diff line number Diff line change
Expand Up @@ -4,50 +4,54 @@
A built-in boolean type.
</brief_description>
<description>
A [bool] is always one of two values: [code]true[/code] or [code]false[/code], similar to a switch that is either on or off. Booleans are used in programming for logic in condition statements.
Booleans can be directly used in [code]if[/code] and [code]elif[/code] statements. You don't need to add [code]== true[/code] or [code]== false[/code]:
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();
LaunchBullet();
}
[/csharp]
[/codeblocks]
Many common methods and operations return [bool]s, for example, [code]shooting_cooldown &lt;= 0.0[/code] may evaluate to [code]true[/code] or [code]false[/code] depending on the number's value.
[bool]s are usually used with the logical operators [code]and[/code], [code]or[/code], and [code]not[/code] to create complex conditions:
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:
if bullets &gt; 0 and not is_reloading():
launch_bullet()

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

if (bullets == 0 || isReloading)
if (bullets == 0 || IsReloading())
{
playClackSound();
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 default-initialized [bool] set to [code]false[/code].
Constructs a [bool] set to [code]false[/code].
</description>
</constructor>
<constructor name="bool">
Expand All @@ -61,14 +65,14 @@
<return type="bool" />
<param index="0" name="from" type="float" />
<description>
Cast a [float] value to a boolean value. This method will return [code]false[/code] if [code]0.0[/code] is passed in, and [code]true[/code] for all other values.
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. This method will return [code]false[/code] if [code]0[/code] is passed in, and [code]true[/code] for all other values.
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>
Expand All @@ -77,7 +81,7 @@
<return type="bool" />
<param index="0" name="right" type="bool" />
<description>
Returns [code]true[/code] if two bools are different, i.e. one is [code]true[/code] and the other is [code]false[/code].
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;">
Expand All @@ -91,7 +95,7 @@
<return type="bool" />
<param index="0" name="right" type="bool" />
<description>
Returns [code]true[/code] if two bools are equal, i.e. both are [code]true[/code] or both are [code]false[/code].
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;">
Expand Down