isNil: Difference between revisions

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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 code 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.  
 |Parameter 21=
 |Parameter 21=



Revision as of 23:57, 18 September 2019

-wrong parameter ("Arma") defined!-1.00
Hover & click on the images for description

Description

Description:
Tests whether the variable defined by the String argument is undefined, or whether an expression result passed as Code is undefined.
The command returns true if the variable or the expression result is undefined (i.e. the expression result is Nothing), and false in all other cases.
Logo A0.png1.00 isNil doesn't exist in Operation Flashpoint, you can emulate it:

// SQS syntax
_nil = format ["%1", _undefinedVariable]
? (format ["%1", foo] == _nil) : foo = "Hello World!"

// SQF syntax
_nil = format ["%1", _undefinedVariable];
if (format ["%1", foo] == _nil) then { foo = "Hello World!"; };
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.
 
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

Additional Information

See also:
nilVariables

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

Notes

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