View source for Jump

{{LSL Header|ml=*}}{{#if:

{{#vardefine:name|jump}}

{{#vardefine:p_jump_target_desc|Name of a label inside the same function or event scope.}}
{{#vardefine:p_label_target_desc|A label that can be jumped to, if the jump is in the same scope or child scope. It isn't possible to jump between scopes (such as between functions, events or states).}}

{{#vardefine:header_title|jump {{LSL Param|jump_target|target}};}}
{{#vardefine:header_text|{{{!}}
{{LSL DefineRow|label|target|{{#var:p_jump_target_desc}}}}
{{!}}}
}}

{{#vardefine:constants_nb|
<div id="box">
<h2>@{{LSL Param|label_target|target}};</h2>
<div style="padding: 0.5em">
{{{!}}
{{LSL DefineRow|label|target|{{#var:p_label_target_desc}}}}
{{!}}}
</div>
</div>
}}

{{#vardefine:examples|
<syntaxhighlight lang="lsl2">integer a = 5;
jump over;
@in;
a = 6;
@over;
llOwnerSay((string)a);
if(a < 6)
    jump in;
//script will say 5 and then 6</syntaxhighlight>
<syntaxhighlight lang="lsl2">
integer getLinkWithName(string name)
{
    integer i = llGetLinkNumber() != 0;   // Start at zero (single prim) or 1 (two or more prims)
    integer x = llGetNumberOfPrims() + i; // [0, 1) or [1, llGetNumberOfPrims()]
    for (; i < x; ++i) 
    {
        if (llGetLinkName(i) == name) 
            jump break; // Found it! Exit loop early with result
    }
    i = -1; // No prim with that name, return -1.
    @break;
    return i;
}
</syntaxhighlight>
More often than not, the rather ugly 'jump' can be avoided, especially in user defined functions, as this version of the above script demonstrates
<syntaxhighlight lang="lsl2">
integer getLinkWithName(string name)
{
    integer i = llGetLinkNumber() != 0;      // Start at zero (single prim) or 1 (two or more prims)
    integer x = llGetNumberOfPrims() + i; // [0, 1) or [1, llGetNumberOfPrims()]
    for (; i < x; ++i) 
    {
        if (llGetLinkName(i) == name) 
            return i;                    // Found it, return its index        
    }
    return -1;     // No prim with that name, return -1.
}
</syntaxhighlight>

}}

{{#vardefine:notes|
It is generally considered inadvisable to use jumps (commonly know as gotos) where other flow control structures could be used.
* {{Wikipedia|Goto}}
* [http://xkcd.com/292/ XKCD:Goto]
}}

{{#vardefine:lso|
<h5>Multiple Jumps Bug</h5>
The following function, <code>jumpy</code>, demonstrates the multiple-jump-sites-to-a-single-target bug. It appears this function should result in an infinite loop, and it does when the script is compiled for the Mono VM. However when compiled for LSO VM because of this bug the second jump never happens and the function returns. LL reported they were unwilling to fix this bug as to do so would be a breaking change. This bug was fixed in the newer Mono VM.

<syntaxhighlight lang="lsl2">jumpy(){
    jump next;//first jump
    @next;
    jump next;//second jump - BUG never gets executed
    return;
}</syntaxhighlight>

}}

{{#vardefine:caveats|
*'''In [[LSO]] Only:''' If multiple jump sites are declared for the same target label within scope, then only the first (top to bottom, left to right) will function as expected, all others will silently fail.
*Labels are scoped at the event and function level, meaning that it is not possible to declare duplicate labels within the same event or function, even if the labels are enclosed in different if-statements, loops etc. -- {{JIRA|SVC-6712}}
**Attempting this will result in an unhelpful CIL assembly related error. -- {{Jira|SCR-256}}
*If code exists after a return that is not encapsulated in a flow control structure, the compiler will return an error about the code being dead even if the code is accessible with a jump. -- {{Jira|SVC-1929}}
}}

{{Issues/SVC-6712}}
{{Issues/SCR-256}}
{{Issues/SVC-1929}}

{{#vardefine:helpers|}}

{{#vardefine:also_header|<h3>Keywords</h3>
{{{!}}
{{LSL DefineRow||[[return]]|}}
{{LSL DefineRow||[[state]]|}}
{{!}}}
}}

{{#vardefine:also_footer|}}
{{#vardefine:also_functions|}}
{{#vardefine:also_events|}}
{{#vardefine:also_articles|}}
{{#vardefine:also_tests|}}
{{#vardefine:location|}}

}}{{LSL Generic}}{{LSLC|Flow Control}}