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Merged
monty-linden merged 7 commits into from
May 13, 2026
+41 −13
Merged

Added a section about typecasting #20

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71f1dae
Added a section about casting
tapple Dec 20, 2025
528d973
Casting -> Typecasting
tapple Dec 21, 2025
9147d4c
noted that uuid and string are no longer interchangable
tapple Dec 21, 2025
4da71c8
Clarify parentheses necessity in math.modf example
tapple Jan 7, 2026
e8dbef3
Add or expressions to convert nil to the LSL typecast value
tapple Jan 8, 2026
ee5fd1c
Merge remote-tracking branch 'origin/main' into patch-1
tapple Apr 28, 2026
bdb4207
consistently capitalize LSL and Lua
tapple May 1, 2026
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54 changes: 41 additions & 13 deletions src/content/docs/script/learn-lua/from-lsl.mdx
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Original file line number Diff line number Diff line change
Expand Up @@ -26,7 +26,7 @@ You already know how Second Life scripting works—events, permissions, object c
### Comments & Structure

<CodeComparison>
<Fragment slot="lsl">
<Fragment slot="LSL">
```lsl
// Single line comment
/* Multi-line
Expand All @@ -49,15 +49,15 @@ local x: number = 5 -- Semicolons optional (rarely used)
### Variables & Types

<CodeComparison>
<Fragment slot="lsl">
<Fragment slot="LSL">
```lsl
// Type declarations required
integer health = 100;
float damage = 25.5;
string name = "Alice";
vector pos = <10, 20, 30>;
rotation rot = <0, 0, 0, 1>;
key uuid = "...";
key k = "...";
list items = [1, 2, 3];
```
</Fragment>
Expand All @@ -69,7 +69,7 @@ local damage: number = 25.5
local name: string = "Alice"
local pos: vector = vector(10, 20, 30)
local rot: quaternion = quaternion(0, 0, 0, 1)
local uuid: string = "..." -- keys are strings
local k: uuid = uuid("...")
local items: {number} = {1, 2, 3} -- tables, not lists
```
</Fragment>
Expand All @@ -79,6 +79,34 @@ local items: {number} = {1, 2, 3} -- tables, not lists
**Type annotations recommended!** While optional, they catch errors before runtime and make code self-documenting.
</Aside>

#### Typecasting
In many cases, Luau does typecasting automatically. Here's how to do it explicitly:
<CodeComparison>
<Fragment slot="LSL">
```lsl
(integer)"-4.4";
(float)"25.5";
(string)99.9;
(vector)"<10, 20, 30>";
(rotation)"<0, 0, 0, 1>";
(key)"700843d3-0d15-c427-81ab-e9c8a0dcdb1e";
(list)"hello"; // equivilant to ["hello"]
```
</Fragment>
<Fragment slot="Lua">
```luau
(math.modf(tonumber("-4.4") or 0)) -- extra parentheses sometimes necessary
tonumber("25.5") or 0
tostring(99.9)
tovector("<10, 20, 30>") or ZERO_VECTOR
toquaternion("<0, 0, 0, 1>") or ZERO_ROTATION
uuid("700843d3-0d15-c427-81ab-e9c8a0dcdb1e") or NULL_KEY
{"hello"} -- table, not list
```
</Fragment>
</CodeComparison>
LSL and Lua typecasts return different results on invalid input: LSL returns "zero"; Lua returns `nil`. The Lua examples include an `or` expressions that converts `nil` to what LSL typecast would have returned

### Operators

| Operation | LSL | Lua | Notes |
Expand All @@ -97,7 +125,7 @@ local items: {number} = {1, 2, 3} -- tables, not lists
### Control Flow

<CodeComparison>
<Fragment slot="lsl">
<Fragment slot="LSL">
```lsl
// if, then, else
if (x > 5) {
Expand Down Expand Up @@ -156,7 +184,7 @@ until count >= 10
### Functions

<CodeComparison>
<Fragment slot="lsl">
<Fragment slot="LSL">
```lsl
float calculateDamage(float base, float mult) {
return base * mult;
Expand Down Expand Up @@ -190,7 +218,7 @@ Tables are Lua's most powerful data structure. Unlike LSL's separate `list` type
#### Tables as Arrays (LSL list replacement)

<CodeComparison>
<Fragment slot="lsl">
<Fragment slot="LSL">
```lsl
list items = [10, 20, 30, 40];

Expand Down Expand Up @@ -287,7 +315,7 @@ ll.Say(0, `Name: {data.name}`) -- "Alice"
### String Operations

<CodeComparison>
<Fragment slot="lsl">
<Fragment slot="LSL">
```lsl
string msg = "Hello" + " " + "World";
string name = "Alice";
Expand All @@ -312,7 +340,7 @@ local sub: string = string.sub(msg, 1, 5) -- "Hello" (1-based!)
### ll* Functions

<CodeComparison>
<Fragment slot="lsl">
<Fragment slot="LSL">
```lsl
llSay(0, "Hello");
llSetPos(<10, 20, 30>);
Expand All @@ -337,7 +365,7 @@ ll.GiveInventory(avatar, "Object")
This is the most significant difference between LSL and Lua. Instead of state-based event handlers, Lua uses **event callbacks** with `LLEvents:on()`.

<CodeComparison>
<Fragment slot="lsl">
<Fragment slot="LSL">
```lsl
integer clickCount = 0;

Expand Down Expand Up @@ -418,7 +446,7 @@ end)
## Global Variables

<CodeComparison>
<Fragment slot="lsl">
<Fragment slot="LSL">
```lsl
// All script-level variables are global
integer health = 100;
Expand Down Expand Up @@ -449,7 +477,7 @@ end
### Door Script

<CodeComparison>
<Fragment slot="lsl">
<Fragment slot="LSL">
```lsl
integer isOpen = FALSE;
vector closedPos;
Expand Down Expand Up @@ -495,7 +523,7 @@ end)
### Timer Events

<CodeComparison>
<Fragment slot="lsl">
<Fragment slot="LSL">
```lsl
integer counter = 0;

Expand Down
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