isNil: Difference between revisions
Lou Montana (talk | contribs) m (Text replacement - "[[Category:Scripting_Commands_Take_On_Helicopters" to "[[Category:Scripting Commands Take On Helicopters")  | 
				 (Example 4)  | 
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|p21= code: [[Code]] - code to evaluate:  | |p21= code: [[Code]] - code to evaluate:  | ||
* the code '''will''' be executed; {{Inline code|[[isNil]] { [[player]] [[setDamage]] 1; };}} ''will'' kill the player  | * the code '''will''' be executed; {{Inline code|[[isNil]] { [[player]] [[setDamage]] 1; };}} ''will'' kill the player  | ||
* the code will not be allowed [[canSuspend|to suspend]] while expression is evaluated, even if the parent scope allows it.    | * the code will not be allowed [[canSuspend|to suspend]] while expression is evaluated, even if the parent scope allows it (Example 4).    | ||
 |Parameter 21=  |  |Parameter 21=  | ||
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[[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> |Example 3=  | </code> |Example 3=  | ||
|x4= You can do this trick to force execute something in [[Scheduler|Unscheduled Environment]].<code>[[spawn]] {  | |||
	[[systemChat]] [[str]] [[canSuspend]]; {{cc|[[true]]}}  | |||
	[[isNil]] {[[hint]] [[str]] [[canSuspend]]}; {{cc|[[false]]}}  | |||
};</code> |Example 4=  | |||
____________________________________________________________________________________________  | ____________________________________________________________________________________________  | ||
Revision as of 10:26, 14 May 2020
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:
 - Uncategorised
 
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 (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; // true isNil {hint str canSuspend}; // false }; 
Additional Information
Notes
- 
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