Added literal initializations to Failable type

Sources/Validation/Failable+Helpers/Failable+ExpressibleByLiteral.swift

@@ -0,0 +1,80 @@
+extension Failable: ExpressibleByIntegerLiteral where T: ExpressibleByIntegerLiteral {
+    
+    /// See [`ExpressibleByIntegerLiteral.IntegerLiteralType`](https://developer.apple.com/documentation/swift/expressiblebyintegerliteral/2295254-integerliteraltype).
+    public typealias IntegerLiteralType = T.IntegerLiteralType
+    
+    /// See [`ExpressibleByIntegerLiteral.init(integerLiteral:)`](https://developer.apple.com/documentation/swift/expressiblebyintegerliteral/2298913-init).
+    public init(integerLiteral value: T.IntegerLiteralType) {
+        let t = T.init(integerLiteral: value)
+        try! self.init(t)
+    }
+}
+
+extension Failable: ExpressibleByFloatLiteral where T: ExpressibleByFloatLiteral {
+    
+    /// See [`ExpressibleByFloatLiteral.FloatLiteralType`](https://developer.apple.com/documentation/swift/expressiblebyfloatliteral/2296813-floatliteraltype).
+    public typealias FloatLiteralType = T.FloatLiteralType
+    
+    /// See [`ExpressibleByFloatLiteral.init(floatLiteral:)`](https://developer.apple.com/documentation/swift/expressiblebyfloatliteral/2294405-init).
+    public init(floatLiteral value: T.FloatLiteralType) {
+        let t = T.init(floatLiteral: value)
+        try! self.init(t)
+    }
+}
+
+extension Failable: ExpressibleByBooleanLiteral where T: ExpressibleByBooleanLiteral {
+    
+    /// See [`ExpressibleByBooleanLiteral.BooleanLiteralType`](https://developer.apple.com/documentation/swift/expressiblebybooleanliteral/2296130-booleanliteraltype).
+    public typealias BooleanLiteralType = T.BooleanLiteralType
+    
+    /// See [`ExpressibleByBooleanLiteral.init(booleanLiteral:)`](https://developer.apple.com/documentation/swift/expressiblebybooleanliteral/2296011-init).
+    public init(booleanLiteral value: T.BooleanLiteralType) {
+        let t = T.init(booleanLiteral: value)
+        try! self.init(t)
+    }
+}
+
+extension Failable: ExpressibleByNilLiteral where T: ExpressibleByNilLiteral {
+    
+    /// See [`ExpressibleByNilLiteral.init(nilLiteral:)`](https://developer.apple.com/documentation/swift/expressiblebynilliteral).
+    public init(nilLiteral: ()) {
+        let t = T.init(nilLiteral: ())
+        try! self.init(t)
+    }
+}
+
+extension Failable: ExpressibleByStringLiteral where T: ExpressibleByStringLiteral {
+    
+    /// See [`ExpressibleByStringLiteral.StringLiteralType`](https://developer.apple.com/documentation/swift/expressiblebystringliteral/2295780-stringliteraltype).
+    public typealias StringLiteralType = T.StringLiteralType
+    
+    /// See [`ExpressibleByStringLiteral.init(stringLiteral:)`](https://developer.apple.com/documentation/swift/expressiblebystringliteral/2294174-init)
+    public init(stringLiteral value: T.StringLiteralType) {
+        let t = T.init(stringLiteral: value)
+        try! self.init(t)
+    }
+}
+
+extension Failable: ExpressibleByExtendedGraphemeClusterLiteral where T: ExpressibleByExtendedGraphemeClusterLiteral {
+    
+    /// See [`ExpressibleByExtendedGraphemeClusterLiteral.ExtendedGraphemeClusterLiteralType`](https://developer.apple.com/documentation/swift/expressiblebyextendedgraphemeclusterliteral/2297729-extendedgraphemeclusterliteralty).
+    public typealias ExtendedGraphemeClusterLiteralType = T.ExtendedGraphemeClusterLiteralType
+    
+    /// See [`ExpressibleByExtendedGraphemeClusterLiteral.init(extendedGraphemeClusterLiteral:)`](https://developer.apple.com/documentation/swift/expressiblebyextendedgraphemeclusterliteral/2294280-init).
+    public init(extendedGraphemeClusterLiteral value: T.ExtendedGraphemeClusterLiteralType) {
+        let t = T.init(extendedGraphemeClusterLiteral: value)
+        try! self.init(t)
+    }
+}
+
+extension Failable: ExpressibleByUnicodeScalarLiteral where T: ExpressibleByUnicodeScalarLiteral {
+    
+    /// See [`ExpressibleByUnicodeScalarLiteral.UnicodeScalarLiteralType`](https://developer.apple.com/documentation/swift/expressiblebyunicodescalarliteral/2297763-unicodescalarliteraltype).
+    public typealias UnicodeScalarLiteralType = T.UnicodeScalarLiteralType
+    
+    /// See [`ExpressibleByUnicodeScalarLiteral.init(unicodeScalarLiteral:)`](https://developer.apple.com/documentation/swift/expressiblebyunicodescalarliteral/2296043-init).
+    public init(unicodeScalarLiteral value: T.UnicodeScalarLiteralType) {
+        let t = T.init(unicodeScalarLiteral: value)
+        try! self.init(t)
+    }
+}

Sources/Validation/Failable.swift

@@ -8,6 +8,8 @@
 ///
 ///     try "the quick brown fox...".failable(Length1028.self)
 ///
+/// ## Mutation
+///
 /// A `Failable` type is a struct, so the stored value can only be mutated if the `Failable` instance is a variable.
 /// The stored value does not make its setter public, because then you would be able to set the value directly and bypass the validations.
 /// Instead you use the `<~` operator to assign a new value:
@@ -19,6 +21,18 @@
 ///
 ///     var story = try "the quick brown fox...".failable(Length1028.self)
 ///     print(story.value)
+///
+/// ## Literal Initialization
+///
+/// `Failable` supprts initialization with certain type literals if the `value` type `T` also supports it.
+/// Initialization is supported for `Int`, `Float`, `Bool`, `nil`, and `String` types.
+///
+///     let string = Failable<String, EmptyValidationM<String>> = "Hello world"
+///
+/// - Warning: Because literal initializers cannot fail, your program will crash if the value passed in does not pass validation.
+///
+/// `Dictionary` and `Array` types are not supported for literal initialization yet because array
+/// splatting for variadic parameters is not supported yet.
 public struct Failable<T, Validations> where Validations: Validation, Validations.Supported == T {
     
     /// The underlaying value that has been validated.