# IdentifiableExpression

    protocol IdentifiableExpression : https://developers.home.google.com/reference/swift/GoogleHomeSDK/Protocols/Expression.html, Identifiable where Self.ID == String

Represent a complex expression with one operator and one or more operand(s).

Depending on the operator type, it may represent:

- Arithmetic (plus, minus, etc.) expressions,
- Comparison (equals, greaterThan, etc.) expressions,
- Logical (and, or, etc.) expressions,
- Struct traversal (fieldSelect) expressions,
- List accessor (listSize, listContains, etc.) expressions,
- Comprehension (listAnyMatch, listFilter, etc.) expressions.
- `


  ### [id](https://developers.home.google.com/reference/swift/GoogleHomeSDK/Protocols/IdentifiableExpression#/s:13GoogleHomeSDK22IdentifiableExpressionP2idSSvp)


  ` String identifier of the expression. Must be unique within a single automation graph.

  #### Declaration

  Swift

      override var id: String { get }