---
title: Expression
framework: foundation
role: symbol
role_heading: Structure
path: foundation/expression
---

# Expression

## Declaration

```swift
struct Expression<each Input, Output>
```

## Topics

### Initializers

- [init(_:)](foundation/expression/init(_:).md)

### Instance Properties

- [expression](foundation/expression/expression.md)
- [variable](foundation/expression/variable.md)

### Instance Methods

- [evaluate(_:)](foundation/expression/evaluate(_:).md)

## Relationships

### Conforms To

- [Copyable](swift/copyable.md)
- [CustomDebugStringConvertible](swift/customdebugstringconvertible.md)
- [CustomStringConvertible](swift/customstringconvertible.md)
- [Decodable](swift/decodable.md)
- [DecodableWithConfiguration](foundation/decodablewithconfiguration.md)
- [Encodable](swift/encodable.md)
- [EncodableWithConfiguration](foundation/encodablewithconfiguration.md)
- [Escapable](swift/escapable.md)
- [Sendable](swift/sendable.md)
- [SendableMetatype](swift/sendablemetatype.md)

## See Also

### Structures

- [AsyncCharacterSequence](foundation/asynccharactersequence.md)
- [AsyncLineSequence](foundation/asynclinesequence.md)
- [AsyncUnicodeScalarSequence](foundation/asyncunicodescalarsequence.md)
- [NSAttributedStringFormattingContextKey](foundation/nsattributedstringformattingcontextkey.md)
- [NSKeyValueChangeKey](foundation/nskeyvaluechangekey.md)
- [NSKeyValueObservedChange](foundation/nskeyvalueobservedchange.md)
- [NSKeyValueOperator](foundation/nskeyvalueoperator.md)
- [PresentationIntent](foundation/presentationintent.md)