Improved inits and added static inits

Sources/SwiftASCII/ASCIICharacter.swift

@@ -33,6 +33,25 @@ public struct ASCIICharacter: Hashable {
 
 	}
 
+	@inlinable public init(_ lossy: Character) {
+
+		guard let getASCIIValue = lossy.asciiValue else {
+			// if ASCII encoding fails, fall back to a default character instead of throwing an exception
+
+			var translated = String(lossy).asciiStringLossy
+			if translated.stringValue.isEmpty { translated = "?" }
+
+			characterValue = Character(translated.stringValue)
+			asciiValue = characterValue.asciiValue ?? 0x3F
+
+			return
+		}
+
+		characterValue = lossy
+		asciiValue = getASCIIValue
+
+	}
+
 	@inlinable public init?(exactly source: String) {
 
 		guard source.count == 1,
@@ -47,7 +66,14 @@ public struct ASCIICharacter: Hashable {
 		asciiValue = getASCIIValue
 
 	}
-
+
+	@inlinable public init(_ lossy: String) {
+
+		let char: Character = lossy.first ?? "?"
+
+		self.init(char)
+
+	}
 
 	@inlinable public init?(exactly source: Data) {
 
@@ -82,20 +108,7 @@ extension ASCIICharacter: ExpressibleByExtendedGraphemeClusterLiteral {
 
 	public init(extendedGraphemeClusterLiteral value: Character) {
 
-		guard let getASCIIValue = value.asciiValue else {
-			// if ASCII encoding fails, fall back to a default character instead of throwing an exception
-
-			var translated = String(value).asciiStringLossy
-			if translated.stringValue.isEmpty { translated = "?" }
-
-			characterValue = Character(translated.stringValue)
-			asciiValue = characterValue.asciiValue ?? 0x3F
-
-			return
-		}
-
-		characterValue = value
-		asciiValue = getASCIIValue
+		self.init(value)
 
 	}
 
@@ -156,3 +169,37 @@ extension ASCIICharacter: Equatable {
 	}
 
 }
+
+extension ASCIICharacter {
+
+	/// Convenience syntactic sugar
+	public static func exactly(_ source: Character) -> ASCIICharacter? {
+		Self(exactly: source)
+	}
+
+	/// Convenience syntactic sugar
+	public static func lossy(_ source: Character) -> ASCIICharacter {
+		Self(source)
+	}
+
+	/// Convenience syntactic sugar
+	public static func exactly(_ source: String) -> ASCIICharacter? {
+		Self(exactly: source)
+	}
+
+	/// Convenience syntactic sugar
+	public static func lossy(_ source: String) -> ASCIICharacter {
+		Self(source)
+	}
+
+	/// Convenience syntactic sugar
+	public static func exactly(_ source: Data) -> ASCIICharacter? {
+		Self(exactly: source)
+	}
+
+	/// Convenience syntactic sugar
+	public static func exactly<T: BinaryInteger>(_ value: T) -> ASCIICharacter? {
+		Self(value)
+	}
+
+}

Sources/SwiftASCII/ASCIIString.swift

@@ -9,7 +9,7 @@
 import Foundation
 
 /// A type containing a String instance that is guaranteed to conform to ASCII encoding.
-public struct ASCIIString: Equatable, Hashable {
+public struct ASCIIString: Hashable {
 
 	/// The ASCII string returned as a `String`
 	public let stringValue: String
@@ -39,28 +39,34 @@ public struct ASCIIString: Equatable, Hashable {
 
 	}
 
-}
-
-extension ASCIIString: ExpressibleByStringLiteral {
-
-	public typealias StringLiteralType = String
-
-	@inlinable public init(stringLiteral: String) {
+	@inlinable public init(_ lossy: String) {
 
-		guard stringLiteral.allSatisfy({ $0.isASCII }),
-			  let asciiData = stringLiteral.data(using: .ascii) else {
+		guard lossy.allSatisfy({ $0.isASCII }),
+			  let asciiData = lossy.data(using: .ascii) else {
 
 			// if ASCII encoding fails, fall back to a default string instead of throwing an exception
 
-			stringValue = stringLiteral.asciiStringLossy.stringValue
+			stringValue = lossy.asciiStringLossy.stringValue
 			rawData = stringValue.data(using: .ascii) ?? Data([])
 			return
 		}
 
-		stringValue = stringLiteral
+		stringValue = lossy
 		rawData = asciiData
 
 	}
+
+}
+
+extension ASCIIString: ExpressibleByStringLiteral {
+
+	public typealias StringLiteralType = String
+
+	@inlinable public init(stringLiteral: String) {
+
+		self.init(stringLiteral)
+
+	}
 
 }
 
@@ -82,13 +88,11 @@ extension ASCIIString: CustomDebugStringConvertible {
 
 extension ASCIIString: LosslessStringConvertible {
 
-	public init?(_ description: String) {
-		self.init(exactly: description)
-	}
+	// required init already implemented above
 
 }
 
-extension ASCIIString {
+extension ASCIIString: Equatable {
 
 	public static func == <T: StringProtocol>(lhs: Self, rhs: T) -> Bool {
 		lhs.stringValue == rhs
@@ -107,3 +111,22 @@ extension ASCIIString {
 	}
 
 }
+
+extension ASCIIString {
+
+	/// Convenience syntactic sugar
+	public static func exactly(_ source: String) -> ASCIIString? {
+		Self(exactly: source)
+	}
+
+	/// Convenience syntactic sugar
+	public static func exactly(_ source: Data) -> ASCIIString? {
+		Self(exactly: source)
+	}
+
+	/// Convenience syntactic sugar
+	public static func lossy(_ source: String) -> ASCIIString {
+		Self(source)
+	}
+
+}

Sources/SwiftASCII/String.swift

@@ -10,6 +10,14 @@ import Foundation
 
 extension String {
 
+	/// Converts a String to `ASCIIString` exactly.
+	/// Returns nil if `self` is not encodable as ASCII.
+	@inlinable public var asciiString: ASCIIString? {
+		ASCIIString(exactly: self)
+	}
+
+	/// Converts a String to `ASCIIString` lossily.
+	///
 	/// Performs a lossy conversion, transforming characters to printable ASCII substitutions where necessary.
 	///
 	/// Note that some characters may be transformed to representations that occupy more than one ASCII character. For example: char 189 (½) will be converted to "1/2"
@@ -24,7 +32,7 @@ extension String {
 							   reverse: false)
 
 		let components =
-			(transformed ?? self)
+			(transformed ?? Self(self))
 			.components(separatedBy: CharacterSet.asciiPrintable.inverted)
 
 		return ASCIIString(exactly: components.joined(separator: "?"))
@@ -35,3 +43,27 @@ extension String {
 	}
 
 }
+
+extension Substring {
+
+	/// Converts a String to `ASCIIString` exactly.
+	/// Returns nil if `self` is not encodable as ASCII.
+	@inlinable public var asciiString: ASCIIString? {
+		ASCIIString(exactly: String(self))
+	}
+
+	/// Converts a String to `ASCIIString` lossily.
+	///
+	/// Performs a lossy conversion, transforming characters to printable ASCII substitutions where necessary.
+	///
+	/// Note that some characters may be transformed to representations that occupy more than one ASCII character. For example: char 189 (½) will be converted to "1/2"
+	///
+	/// Where a suitable character substitution can't reasonably be performed, a question-mark "?" will be substituted.
+	@available(OSX 10.11, iOS 9.0, *)
+	public var asciiStringLossy: ASCIIString {
+
+		String(self).asciiStringLossy
+
+	}
+
+}

Tests/SwiftASCIITests/ASCIICharacter Tests.swift

@@ -132,6 +132,30 @@ class ASCIICharacterTests: XCTestCase {
 
 	}
 
+	func testStaticInits() {
+
+		let str: ASCIICharacter = .lossy("😃")
+
+		XCTAssertEqual(str.characterValue, Character("?"))
+
+		let _: [ASCIICharacter] = [.lossy("A"),
+								   .lossy("A string"),
+								   .lossy(Character("A")),
+								   .exactly(Character("A"))!,
+								   .exactly("A")!,
+								   .exactly(Data([65]))!,
+								   .exactly(65)!]
+
+		let _: [ASCIICharacter?] = [.lossy("A"),
+									.lossy("A string"),
+									.lossy(Character("A")),
+									.exactly(Character("A"))!,
+									.exactly("A")!,
+									.exactly(Data([65]))!,
+									.exactly(65)!]
+
+	}
+
 }
 
 #endif

Tests/SwiftASCIITests/ASCIIString Tests.swift

@@ -46,6 +46,19 @@ class ASCIIStringTests: XCTestCase {
 
 	}
 
+	func testInit_StringVariable() {
+
+		let str1 = ""
+		XCTAssertEqual(ASCIIString(str1).stringValue, "" as String)
+
+		let str2 = "A string"
+		XCTAssertEqual(ASCIIString(str2).stringValue, "A string" as String)
+
+		let str3 = "Emöji 😃"
+		XCTAssertEqual(ASCIIString(str3).stringValue, "Emoji ?" as String)
+
+	}
+
 	func testInit_stringLiteral() {
 
 		// init(stringLiteral:)
@@ -86,6 +99,22 @@ class ASCIIStringTests: XCTestCase {
 
 	}
 
+	func testStaticInits() {
+
+		let str: ASCIIString = .lossy("Emöji 😃")
+
+		XCTAssertEqual(str.stringValue, "Emoji ?" as String)
+
+		let _: [ASCIIString] = [.lossy("A string"),
+								.exactly("")!,
+								.exactly(Data([65]))!]
+
+		let _: [ASCIIString?] = [.lossy("A string"),
+								 .exactly("")!,
+								 .exactly(Data([65]))!]
+
+	}
+
 }
 
 #endif

Tests/SwiftASCIITests/String Tests.swift

@@ -16,6 +16,24 @@ class StringTests: XCTestCase {
 	override func setUp() { super.setUp() }
 	override func tearDown() { super.tearDown() }
 
+	func testString_asciiString() {
+
+		// String
+
+		XCTAssertEqual("An ASCII String.".asciiString?.stringValue,
+					   "An ASCII String.")
+
+		XCTAssertNil("Ãñ ÂŚÇÏÎ Strïńg.".asciiString)
+
+		// Substring
+
+		XCTAssertEqual(Substring("An ASCII String.").asciiString?.stringValue,
+					   "An ASCII String.")
+
+		XCTAssertNil(Substring("Ãñ ÂŚÇÏÎ Strïńg.").asciiString)
+
+	}
+
 	func testString_asciiStringLossy() {
 
 		// printable ASCII chars - ensure they are kept intact and not translated