Difference between revisions of "Category:LSL Types"

From Second Life Wiki
Jump to navigation Jump to search
(reword the footnote)
 
(2 intermediate revisions by 2 users not shown)
Line 7: Line 7:


===Example===
===Example===
<lsl>integer myVar = 123;</lsl>
<source lang="lsl2">integer myVar = 123;</source>


== Pass‑by‑value ==
== Pass‑by‑value ==
[[LSL]] as a language uses pass‑by‑value for all types{{Footnote|The VMs that run compiled scripts however do use reference types and pass‑by‑reference, they just ensure copies are made.}}. When a value (it can be the value in a variable) is passed as a parameter to a function, that function is provided with it's own unique copy of the value. So if in the course of executing the function, the function modifies the parameter, that modification only changes the functions copy of the value, it does not effect or change the original (or other copies).
[[LSL]] as a language uses pass‑by‑value for all types{{Footnote|The VMs that run compiled scripts however do use reference types and pass‑by‑reference. In practice this means passing a large list or string as a parameter is not quite as memory ineffecient as it might seem: the passed variable becomes a full-sized copy only if it needs to be modified.}}. When a value (it can be the value in a variable) is passed as a parameter to a function, that function is provided with it's own unique copy of the value. So if in the course of executing the function, the function modifies the parameter, that modification only changes the functions copy of the value, it does not effect or change the original (or other copies).


*[[:Category:LSL Functions|Built in functions]] will never modify the variables used as parameters.
*[[:Category:LSL Functions|Built in functions]] will never modify the variables used as parameters.
Line 16: Line 16:


===Example===
===Example===
<lsl>//This demonstrates that LSL (as a language) is pass‑by‑value, if it were pass‑by‑reference, the lines said would be different.
<source lang="lsl2">//This demonstrates that LSL (as a language) is pass‑by‑value, if it were pass‑by‑reference, the lines said would be different.
swap(string a, string b){
swap(string a, string b){
     string t = a;
     string t = a;
Line 31: Line 31:
         llOwnerSay(llList2CSV([a, b]));
         llOwnerSay(llList2CSV([a, b]));
     }
     }
}</lsl>
}</source>
 
===Footnotes===
{{Footnotes}}

Latest revision as of 07:11, 18 October 2023

Introduction

A data type is a definition of the type or format of data.

An integer for example, defines that the variable which will hold this kind (or 'type') of data shall contain only integers, which for 32-bit are whole number values in the range of 0x00000000 to 0xFFFFFFFF.

Example

integer myVar = 123;

Pass‑by‑value

LSL as a language uses pass‑by‑value for all types[1]. When a value (it can be the value in a variable) is passed as a parameter to a function, that function is provided with it's own unique copy of the value. So if in the course of executing the function, the function modifies the parameter, that modification only changes the functions copy of the value, it does not effect or change the original (or other copies).

  • Built in functions will never modify the variables used as parameters.
  • User functions that change the values of parameters inside the function scope will not have those changes applied to the variables that supplied those parameters.

Example

//This demonstrates that LSL (as a language) is pass‑by‑value, if it were pass‑by‑reference, the lines said would be different.
swap(string a, string b){
    string t = a;
    a = b;
    b = t;
}

default {
    state_entry(){
        string a = "1";
        string b = "2";
        llOwnerSay(llList2CSV([a, b]));
        swap(a, b);//fails to mutate a or b.
        llOwnerSay(llList2CSV([a, b]));
    }
}

Footnotes

  1. ^ The VMs that run compiled scripts however do use reference types and pass‑by‑reference. In practice this means passing a large list or string as a parameter is not quite as memory ineffecient as it might seem: the passed variable becomes a full-sized copy only if it needs to be modified.

Subcategories

This category has the following 8 subcategories, out of 8 total.

Pages in category "LSL Types"

The following 7 pages are in this category, out of 7 total.