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The generateRBXMX() function generates RBXMX XML model file content from a compiled StyleSheetIR. The output can be saved as a .rbxmx file and imported into Roblox Studio.
RBXMX output is currently experimental. StyleRule properties are emitted as XML comments rather than fully encoded RBXMX properties. The Luau format is recommended for production use.

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Signature

function generateRBXMX(ir: StyleSheetIR): string

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Parameters

​
ir
StyleSheetIR
required
The compiled intermediate representation from compile(). See types for the full structure

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Returns

​
rbxmx
string
Generated RBXMX XML content as a string. The output contains a StyleSheet instance with child StyleRule instances

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Example

import { compile, generateRBXMX } from "rbx-css";

const result = compile(
  [{ filename: "styles.css", content: "div { background-color: red; }" }],
  { name: "MyStyleSheet", warnLevel: "all", strict: false }
);

const rbxmx = generateRBXMX(result.ir);

console.log(rbxmx);
// <roblox version="4">
//   <Item class="StyleSheet" referent="RBX0001">
//     <Properties>
//       <string name="Name">MyStyleSheet</string>
//     </Properties>
//     ...
//   </Item>
// </roblox>

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Output structure

The generated RBXMX follows this structure: 
<roblox version="4">
  <Item class="StyleSheet" referent="RBX0001">
    <Properties>
      <string name="Name">MyStyleSheet</string>
    </Properties>
    
    <!-- Tokens -->
    <!-- --primary: #335fff -->
    <!-- --radius: UDim(0, 8) -->
    
    <Item class="StyleRule" referent="RBX0002">
      <Properties>
        <string name="Selector">.card</string>
      </Properties>
      <!-- Properties:
        BackgroundColor3 = Color3(255, 0, 0)
        Size = UDim2(1, 0, 0, 200)
      -->
    </Item>
  </Item>
  
  <!-- Theme StyleSheets (if present) -->
  <Item class="StyleSheet" referent="RBX0003">
    <Properties>
      <string name="Name">MyStyleSheet_dark</string>
    </Properties>
  </Item>
</roblox>

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Limitations

The RBXMX format currently has the following limitations:
  • Properties as comments — StyleRule properties are written as XML comments instead of encoded RBXMX property values. This means you cannot directly use the imported model in-game without manual configuration
  • No property encoding — Token attributes and StyleRule properties require manual Roblox Studio setup
  • Experimental status — This format may change in future versions

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Use cases

Despite the limitations, RBXMX output is useful for:
  • Visual inspection — View the structure of the compiled StyleSheet in Roblox Studio
  • Manual editing — Create a base structure that you can configure manually
  • Debugging — Compare the generated structure with expected output
For production use, the Luau format is recommended as it generates fully functional code.

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XML escaping

The following characters in names and values are automatically escaped:
  • & → &amp;
  • < → &lt;
  • > → &gt;
  • " → &quot;
This ensures that selectors like .w-\[22px\] or special characters in token names are safely encoded.

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