# IExpressionRuntime interface

Namespace: [Grasshopper2.Expressions](https://developer.rhino3d.com/api/gh2/namespace/grasshopper2.expressions.md) · Assembly: [Grasshopper2](https://developer.rhino3d.com/api/gh2/assembly/grasshopper2.md)

```cs
[EditorBrowsable(EditorBrowsableState.Never)]
public interface IExpressionRuntime
```

Interface for expression runtime assemblies.

## Properties

- [Undeclareds](https://developer.rhino3d.com/api/gh2/type/grasshopper2.expressions.iexpressionruntime/undeclareds.md): Enumerate over all undeclared externals in this expression.

## Methods

- [Process](https://developer.rhino3d.com/api/gh2/type/grasshopper2.expressions.iexpressionruntime/process.md): Process the expression.