isNil: Difference between revisions
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Lou Montana (talk | contribs) m (Text replacement - " <h3 style="display:none">Notes</h3> <dl class="command_description"> <!-- Note Section BEGIN --> <!-- Note Section END --> </dl> " to "") |
Lou Montana (talk | contribs) m (Text replacement - " *\| *([Cc]omments|COMMENTS|Game|[Gg]ame [Nn]ame|Game [Vv]ersion|Game Version \(number surrounded by NO SPACES\)|Multiplayer Arguments( \("local" or "global"\))?|Effects|Multiplayer Effects( \("local" or "global"\))?|Multiplayer Exe...) |
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{{Command | {{Command | ||
| arma1 | | arma1 | ||
|1.00 | |1.00 | ||
|gr1= Variables | |gr1= Variables | ||
| Tests whether the variable given by its name is [[nil]] or undefined, or whether the given expression evaluates to [[nil]] or [[Nothing]]. | | Tests whether the variable given by its name is [[nil]] or undefined, or whether the given expression evaluates to [[nil]] or [[Nothing]]. | ||
{{Informative | {{GVI|ofp|1.00}} This command doesn't exist in {{ofp}} but can be emulated (see '''[[#Examples|Example 5]]''').}} | {{Informative | {{GVI|ofp|1.00}} This command doesn't exist in {{ofp}} but can be emulated (see '''[[#Examples|Example 5]]''').}} | ||
| [[isNil]] variableName | | [[isNil]] variableName | ||
|p1= variableName: [[String]] - name of a [[missionNamespace]] variable (e.g "someVar") or a local variable (e.g "_someVar") | |p1= variableName: [[String]] - name of a [[missionNamespace]] variable (e.g "someVar") or a local variable (e.g "_someVar") | ||
| [[Boolean]] - [[true]] if variable is [[nil]] | | [[Boolean]] - [[true]] if variable is [[nil]] | ||
|s2= [[isNil]] code |Syntax 2= | |s2= [[isNil]] code |Syntax 2= | ||
| Line 22: | Line 22: | ||
* the code will not be allowed [[canSuspend|to suspend]] while expression is evaluated, even if the parent scope allows it (see '''[[#Examples|Example 4]]'''). |Parameter 21= | * the code will not be allowed [[canSuspend|to suspend]] while expression is evaluated, even if the parent scope allows it (see '''[[#Examples|Example 4]]'''). |Parameter 21= | ||
|r2= [[Boolean]] - [[true]] if code returns something other than [[Nothing]] | |r2= [[Boolean]] - [[true]] if code returns something other than [[Nothing]] | ||
|x1= <code>[[if]] ([[isNil]] "pokus") [[then]] { pokus = 0; };</code> | |x1= <code>[[if]] ([[isNil]] "pokus") [[then]] { pokus = 0; };</code> | ||
|x2= <code>[[isNil]] { [[player]] [[getVariable]] "someVar" };</code> | |x2= <code>[[isNil]] { [[player]] [[getVariable]] "someVar" };</code> | ||
|x3= <code>_myArray = [0, 1]; | |x3= <code>_myArray = [0, 1]; | ||
| Line 33: | Line 33: | ||
[[isNil]] { _myArray [[select]] 2 }; {{cc|returns [[true]]}} | [[isNil]] { _myArray [[select]] 2 }; {{cc|returns [[true]]}} | ||
[[isNil]] { _myArray [[select]] 3 }; {{cc|throws a script error. only length+1 select is allowed}} | [[isNil]] { _myArray [[select]] 3 }; {{cc|throws a script error. only length+1 select is allowed}} | ||
</code> | </code> | ||
|x4= You can do this trick to force execute something in [[Scheduler|Unscheduled Environment]].<code>[[spawn]] { | |x4= You can do this trick to force execute something in [[Scheduler|Unscheduled Environment]].<code>[[spawn]] { | ||
[[systemChat]] [[str]] [[canSuspend]]; {{cc|chat shows [[true]]}} | [[systemChat]] [[str]] [[canSuspend]]; {{cc|chat shows [[true]]}} | ||
[[isNil]] {[[hint]] [[str]] [[canSuspend]]}; {{cc|hint shows [[false]]}} | [[isNil]] {[[hint]] [[str]] [[canSuspend]]}; {{cc|hint shows [[false]]}} | ||
};</code> | };</code> | ||
|x5= {{ofp}} workaround:<br>SQS syntax: | |x5= {{ofp}} workaround:<br>SQS syntax: | ||
| Line 46: | Line 46: | ||
<code>_nil = [[format]] ["%1", _undefinedVariable]; | <code>_nil = [[format]] ["%1", _undefinedVariable]; | ||
[[if]] ([[format]] ["%1", foo] == _nil) [[then]] { foo = "value"; };</code> | [[if]] ([[format]] ["%1", foo] == _nil) [[then]] { foo = "value"; };</code> | ||
| [[nil]], [[Variables]], [[Scheduler]] | |||
| [[nil]], [[Variables]], [[Scheduler]] | |||
}} | }} | ||
Revision as of 00:39, 18 January 2021
Description
- Description:
- Tests whether the variable given by its name is nil or undefined, or whether the given expression evaluates to nil or Nothing.
- Groups:
- Variables
Syntax
- Syntax:
- isNil variableName
- Parameters:
- variableName: String - name of a missionNamespace variable (e.g "someVar") or a local variable (e.g "_someVar")
- Return Value:
- Boolean - true if variable is nil
Alternative Syntax
- Syntax:
- isNil code
- Parameters:
- code: Code - code to evaluate:
- the code will be executed;
isNil { player setDamage 1; };will kill the player - the code will not be allowed to suspend while expression is evaluated, even if the parent scope allows it (see Example 4).
- the code will be executed;
- Return Value:
- Boolean - true if code returns something other than Nothing
Examples
- Example 1:
if (isNil "pokus") then { pokus = 0; };- Example 2:
isNil { player getVariable "someVar" };- Example 3:
_myArray = [0, 1]; isNil { _myArray select 0 }; // returns false isNil { _myArray select 1 }; // returns false isNil { _myArray select 2 }; // returns true isNil { _myArray select 3 }; // throws a script error. only length+1 select is allowed- Example 4:
- You can do this trick to force execute something in Unscheduled Environment.
spawn { systemChat str canSuspend; // chat shows true isNil {hint str canSuspend}; // hint shows false }; - Example 5:
- Operation Flashpoint workaround:
SQS syntax:_nil = format ["%1", _undefinedVariable] ? (format ["%1", foo] == _nil) : foo = "value"SQF syntax:_nil = format ["%1", _undefinedVariable]; if (format ["%1", foo] == _nil) then { foo = "value"; };
Additional Information
Notes
-
Report bugs on the Feedback Tracker and/or discuss them on the Arma Discord or on the Forums.
Only post proven facts here! Add Note