Streamlining.

Author: johnno1962

stdlib/public/core/UnicodeScalar.swift

@@ -364,6 +364,15 @@ extension UInt8 {
         "Code point value does not fit into ASCII")
     self = UInt8(v.value)
   }
+  /// Initializes a UInt8 with the ASCII value of the provided Unicode scalar if possible.
+  ///
+  /// - Parameter unicode: The Unicode scalar to initialize from.
+  /// - Note: Construct with value `v.value`.
+  @inlinable @_alwaysEmitIntoClient
+  public init?(ifASCII v: Unicode.Scalar) {
+    guard v.value < 128 else { return nil }
+    self = Self(v.value)
+  }
 }
 extension UInt32 {
   /// Construct with value `v.value`.
@@ -380,51 +389,6 @@ extension UInt64 {
   }
 }
 
-/// Extends `UInt8` providing initialization from a Unicode scalar.
-extension UInt8 {
-  /// Converts a UInt8 ASCII value into a UnicodeScalar
-  @_transparent @_alwaysEmitIntoClient
-  var asciiScalar: Unicode.Scalar? {
-    guard self < 0x80 else { return nil }
-    return Unicode.Scalar(self)
-  }
-  /// Initializes a FixedWidthInteger with the value of the provided Unicode scalar.
-  ///
-  /// - Parameter unicode: The Unicode scalar to initialize from.
-  /// - Note: Construct with value `v.value`.
-  @inlinable @_alwaysEmitIntoClient
-  public init?(ifASCII v: Unicode.Scalar) {
-    guard v.value < 0x80 else { return nil }
-    self = Self(v.value)
-  }
-}
-
-/// Extends `UInt8` to allow direct comparisons with double quoted literals.
-extension UInt8 {
-  /// Returns a Boolean indicating whether the `UInt8` is equal to the provided Unicode scalar.
-  ///
-  /// - Parameters:
-  ///   - i: The `UInt8` value to compare.
-  ///   - s: The Unicode scalar to compare against.
-  /// - Returns: `true` when the `UInt8` is equal to the provided Unicode scalar; otherwise, `false`.
-  @_transparent @_alwaysEmitIntoClient
-  public static func == (i: Self, s: Unicode.Scalar) -> Bool {
-    return i == UInt8(ifASCII: s)
-  }
-
-  /// Returns a Boolean indicating whether the `UInt8` is not equal to the provided Unicode scalar.
-  @_transparent @_alwaysEmitIntoClient
-  public static func != (i: Self, s: Unicode.Scalar) -> Bool {
-    return i != UInt8(ifASCII: s)
-  }
-
-  /// Enables pattern matching of Unicode scalars in switch statements.
-  @_transparent @_alwaysEmitIntoClient
-  public static func ~= (s: Unicode.Scalar, i: Self) -> Bool {
-    return i == UInt8(ifASCII: s)
-  }
-}
-
 /// Extends `Optional<UInt8>` to allow direct comparisons with double quoted literals.
 extension UInt8? {
   /// Returns a Boolean value indicating whether the optional `UInt8` is equal to the provided Unicode scalar.
@@ -462,6 +426,12 @@ extension FixedWidthInteger {
     guard v.value <= Self.max else { return nil }
     self = Self(v.value)
   }
+  /// Converts an ASCII value into a UnicodeScalar
+  @inlinable @_alwaysEmitIntoClient
+  public var asciiScalar: Unicode.Scalar? {
+    guard self < 128 && self >= 0 else { return nil }
+    return Unicode.Scalar(UInt8(self))
+  }
 }
 
 extension Unicode.Scalar: Equatable {

test/Misc/character_ops.swift

@@ -45,6 +45,16 @@ default:
   print("FAIL")
 }
 
+// CHECK: OK
+switch d?.asciiScalar {
+case "a":
+  print("OK")
+case "b":
+  fallthrough
+default:
+  print("FAIL")
+}
+
 // CHECK: OK
 if UInt8(unicode: "a") == "a" {
   print("OK")