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# semantic(forSymbol:)

Returns the SceneKit semantic identifiers associated with the specified GLSL vertex attribute or uniform variable.

```
func semantic(forSymbol symbol: String) -> String?
```

## Parameters

`symbol`

The name declared in the program’s GLSL source code for a vertex attribute or uniform variable semantic.

## Return Value

A SceneKit semantic identifier. See Geometry Semantic Identifiers and Rendering Transform Keys for possible values.

## Discussion

---

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