# Unicode.ASCII ``` @frozen enum ASCII ``` ## Topics ### Structures [`struct Parser`](/documentation/Swift/Unicode/ASCII/Parser) ### Type Aliases [`typealias CodeUnit`](/documentation/Swift/Unicode/ASCII/CodeUnit) The basic unit of encoding [`typealias EncodedScalar`](/documentation/Swift/Unicode/ASCII/EncodedScalar) A valid scalar value as represented in this encoding [`typealias ForwardParser`](/documentation/Swift/Unicode/ASCII/ForwardParser) A type that can be used to parse `CodeUnits` into `EncodedScalar`s. [`typealias ReverseParser`](/documentation/Swift/Unicode/ASCII/ReverseParser) A type that can be used to parse a reversed sequence of `CodeUnits` into `EncodedScalar`s. ### Type Properties [`static var encodedReplacementCharacter: Unicode.ASCII.EncodedScalar`](/documentation/Swift/Unicode/ASCII/encodedReplacementCharacter) A unicode scalar value to be used when repairing encoding/decoding errors, as represented in this encoding. ### Type Methods [`static func decode(Unicode.ASCII.EncodedScalar) -> Unicode.Scalar`](/documentation/Swift/Unicode/ASCII/decode(_:)) Converts from encoded to encoding-independent representation [`static func encode(Unicode.Scalar) -> Unicode.ASCII.EncodedScalar?`](/documentation/Swift/Unicode/ASCII/encode(_:)) Converts from encoding-independent to encoded representation, returning `nil` if the scalar can’t be represented in this encoding. [`static func isASCII(Unicode.ASCII.CodeUnit) -> Bool`](/documentation/Swift/Unicode/ASCII/isASCII(_:)) Returns whether the given code unit represents an ASCII scalar [`static func transcode(FromEncoding.EncodedScalar, from: FromEncoding.Type) -> Unicode.ASCII.EncodedScalar?`](/documentation/Swift/Unicode/ASCII/transcode(_:from:)) Converts a scalar from another encoding’s representation, returning `nil` if the scalar can’t be represented in this encoding. ## Relationships ### Conforms To [`Copyable`](/documentation/Swift/Copyable) [`Escapable`](/documentation/Swift/Escapable) [`BitwiseCopyable`](/documentation/Swift/BitwiseCopyable) [`SendableMetatype`](/documentation/Swift/SendableMetatype) [`Sendable`](/documentation/Swift/Sendable) --- Copyright © 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)