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//===--- UnicodeParser.swift ----------------------------------------------===//
//
// This source file is part of the Swift.org open source project
//
// Copyright (c) 2014 - 2017 Apple Inc. and the Swift project authors
// Licensed under Apache License v2.0 with Runtime Library Exception
//
// See https://swift.org/LICENSE.txt for license information
// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
//
//===----------------------------------------------------------------------===//
extension Unicode {
/// The result of attempting to parse a `T` from some input.
@frozen
public enum ParseResult<T> {
/// A `T` was parsed successfully
case valid(T)
/// The input was entirely consumed.
case emptyInput
/// An encoding error was detected.
///
/// `length` is the number of underlying code units consumed by this
/// error, guaranteed to be greater than 0.
case error(length: Int)
@inlinable
internal var _valid: T? {
if case .valid(let result) = self { return result }
return nil
}
@inlinable
internal var _error: Int? {
if case .error(let result) = self { return result }
return nil
}
}
}
/// Types that separate streams of code units into encoded Unicode
/// scalar values.
public protocol _UnicodeParser {
/// The encoding with which this parser is associated
associatedtype Encoding: _UnicodeEncoding
/// Constructs an instance that can be used to begin parsing `CodeUnit`s at
/// any Unicode scalar boundary.
init()
/// Parses a single Unicode scalar value from `input`.
mutating func parseScalar<I: IteratorProtocol>(
from input: inout I
) -> Unicode.ParseResult<Encoding.EncodedScalar>
where I.Element == Encoding.CodeUnit
}
extension Unicode {
public typealias Parser = _UnicodeParser
}
extension Unicode.ParseResult: Sendable where T: Sendable { }
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