Type safe generic identifiers

Identifier.swift

@dynamicMemberLookup
public struct Identifier<RawValue: Hashable, Type>: Hashable, RawRepresentable {
  
  public var rawValue: RawValue
  
  public init(rawValue: RawValue) {
    self.rawValue = rawValue
  }
  
  public subscript<Value>(dynamicMember keyPath: KeyPath<RawValue, Value>) -> Value {
    get { rawValue[keyPath: keyPath] }
  }
  
  public subscript<Value>(dynamicMember keyPath: WritableKeyPath<RawValue, Value>) -> Value {
    get { rawValue[keyPath: keyPath] }
    set { rawValue[keyPath: keyPath] = newValue }
  }
  
  public subscript<Value>(dynamicMember keyPath: ReferenceWritableKeyPath<RawValue, Value>) -> Value {
    get { rawValue[keyPath: keyPath] }
    set { rawValue[keyPath: keyPath] = newValue }
  }
}

extension Identifier: CustomStringConvertible where RawValue: CustomStringConvertible {
  
  public var description: String {
    rawValue.description
  }
}

extension Identifier: LosslessStringConvertible where RawValue: LosslessStringConvertible {
  
  public init?(_ description: String) {
    guard let rawValue = RawValue(description) else { return nil }
    self.init(rawValue: rawValue)
  }
}

extension Identifier: ExpressibleByUnicodeScalarLiteral where RawValue: ExpressibleByUnicodeScalarLiteral {
  
  public init(unicodeScalarLiteral value: RawValue.UnicodeScalarLiteralType) {
    self.init(rawValue: RawValue(unicodeScalarLiteral: value))
  }
}

extension Identifier: ExpressibleByExtendedGraphemeClusterLiteral where RawValue: ExpressibleByExtendedGraphemeClusterLiteral {
  
  public init(extendedGraphemeClusterLiteral value: RawValue.ExtendedGraphemeClusterLiteralType) {
    self.init(rawValue: RawValue(extendedGraphemeClusterLiteral: value))
  }
}

extension Identifier: ExpressibleByStringLiteral where RawValue: ExpressibleByStringLiteral {
  
  public init(stringLiteral value: RawValue.StringLiteralType) {
    self.init(rawValue: RawValue(stringLiteral: value))
  }
}

extension Identifier: ExpressibleByStringInterpolation where RawValue: ExpressibleByStringInterpolation {
  
  public init(stringInterpolation value: RawValue.StringInterpolation) {
    self.init(rawValue: RawValue(stringInterpolation: value))
  }
}

extension Identifier: ExpressibleByIntegerLiteral where RawValue: ExpressibleByIntegerLiteral {
  
  public init(integerLiteral value: RawValue.IntegerLiteralType) {
    self.init(rawValue: RawValue(integerLiteral: value))
  }
}

extension Identifier: ExpressibleByFloatLiteral where RawValue: ExpressibleByFloatLiteral {
  
  public init(floatLiteral value: RawValue.FloatLiteralType) {
    self.init(rawValue: RawValue(floatLiteral: value))
  }
}

extension Identifier: ExpressibleByNilLiteral where RawValue: ExpressibleByNilLiteral {
  
  public init(nilLiteral: Void) {
    self.init(rawValue: RawValue(nilLiteral: Void()))
  }
}

public func ~=<RawValue: Hashable, Type>(
  _ lhs: RawValue,
  _ rhs: Identifier<RawValue, Type>
) -> Bool {
  lhs == rhs.rawValue
}