throw: Difference between revisions

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m (Text replacement - "<code>([^<]*)\[\[([a-zA-Z][a-zA-Z0-9_]+)\]\]([^<]*) *<\/code>" to "<code>$1$2$3</code>")
m (Fix SQF)
 
(17 intermediate revisions by the same user not shown)
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|descr= Throws an exception. The exception is processed by first [[catch]] block. This command will terminate further execution of the code.
|descr= Throws an exception. The exception is processed by first [[catch]] block. This command will terminate further execution of the code.


{{Feature | important | Avoid using alternative shorthand syntax if you are planning on preparing your exception information dynamically, as it will have to be generated first regardless of the condition of the [[if]] statement before it, as shown in Example 3.}}
{{Feature | important | Avoid using alternative shorthand syntax if you are planning on preparing your exception information dynamically, as it will have to be generated first regardless of the condition of the [[if]] statement before it, as shown in {{Link|#Example 3}}.}}


|s1= [[throw]] expression
|s1= [[throw]] expression
Line 33: Line 33:


|p21= if (condition): [[If Type]]  - if (condition) returns [[true]], "exception" is thrown
|p21= if (condition): [[If Type]]  - if (condition) returns [[true]], "exception" is thrown
|p22= exception: [[Anything]] - value that will be put into ''_exception'' variable inside [[catch]] block
|p22= exception: [[Anything]] - value that will be put into ''_exception'' variable inside [[catch]] block


|r2= [[Nothing]]
|r2= [[Nothing]]


|x1= <code>try {throw "invalid argument"} catch {hint str _exception};</code>
|x1= <sqf>try {throw "invalid argument"} catch {hint str _exception};</sqf>


|x2= <code>123 try {if (_this != 123) throw "invalid argument"} catch {hint str _exception};</code>
|x2= <sqf>123 try { if (_this != 123) throw "invalid argument" } catch { hint str _exception };</sqf>


|x3= The correct usage of shorthand alt syntax:
|x3= The correct usage of shorthand alt syntax:
<code>try {
<sqf>
try {
if (a > b) throw "Error: some error"; // OK
if (a > b) throw "Error: some error"; // OK
// The command argument is static
// the command argument is static
} catch {
} catch {
hint str _exception;
hint str _exception;
Line 51: Line 53:
try {
try {
_someFunc = {
_someFunc = {
.....
// ...
};
};
[[if]] (a > b) [[throw]] ([[call]] _someFunc); // NOT OK
if (a > b) throw (call _someFunc); // NOT OK
// The command argument is dynamic
// The command argument is dynamic
// _someFunc is called first to get the value regardless of (a > b) outcome
// _someFunc is called first to get the value regardless of (a > b) outcome
} [[catch]] {
} catch {
[[hint]] [[str]] _exception;
hint str _exception;
};
};


[[try]] {
try {
_someFunc = {
_someFunc = {
.....
// ...
};
};
[[if]] (a > b) [[then]] {[[throw]] ([[call]] _someFunc)}; /// OK
if (a > b) then {throw (call _someFunc)}; /// OK
// The command argument is dynamic
// the command argument is dynamic
// _someFunc is only called when (a > b) is [[true]]
// _someFunc is only called when (a > b) is true
} [[catch]] {
} catch {
[[hint]] [[str]] _exception;
hint str _exception;
};</code>
};
</sqf>


|seealso= [[Exception handling]] [[try]] [[catch]]
|seealso= [[Exception handling]] [[try]] [[catch]]
}}
}}

Latest revision as of 17:51, 1 November 2022

Hover & click on the images for description

Description

Description:
Throws an exception. The exception is processed by first catch block. This command will terminate further execution of the code.
Avoid using alternative shorthand syntax if you are planning on preparing your exception information dynamically, as it will have to be generated first regardless of the condition of the if statement before it, as shown in Example 3.
Groups:
Program Flow

Syntax

Syntax:
throw expression
Parameters:
expression: Anything
Return Value:
Nothing

Alternative Syntax

Syntax:
if (condition) throw exception
Parameters:
if (condition): If Type - if (condition) returns true, "exception" is thrown
exception: Anything - value that will be put into _exception variable inside catch block
Return Value:
Nothing

Examples

Example 1:
try {throw "invalid argument"} catch {hint str _exception};
Example 2:
123 try { if (_this != 123) throw "invalid argument" } catch { hint str _exception };
Example 3:
The correct usage of shorthand alt syntax:
try { if (a > b) throw "Error: some error"; // OK // the command argument is static } catch { hint str _exception; }; try { _someFunc = { // ... }; if (a > b) throw (call _someFunc); // NOT OK // The command argument is dynamic // _someFunc is called first to get the value regardless of (a > b) outcome } catch { hint str _exception; }; try { _someFunc = { // ... }; if (a > b) then {throw (call _someFunc)}; /// OK // the command argument is dynamic // _someFunc is only called when (a > b) is true } catch { hint str _exception; };

Additional Information

See also:
Exception handling try catch

Notes

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