[stdlib] constistently name param to map/flatMap

Author: Dave Abrahams

stdlib/public/core/Optional.swift

@@ -153,13 +153,16 @@ public enum Optional<Wrapped> : NilLiteralConvertible {
   ///     print(noSquare)
   ///     // Prints "nil"
   ///
-  /// - Parameter f: A closure that takes the unwrapped value of the instance.
+  /// - Parameter transform: A closure that takes the unwrapped value
+  ///   of the instance.
   /// - Returns: The result of the given closure. If this instance is `nil`,
   ///   returns `nil`.
-  public func map<U>(_ f: @noescape (Wrapped) throws -> U) rethrows -> U? {
+  public func map<U>(
+    _ transform: @noescape (Wrapped) throws -> U
+  ) rethrows -> U? {
     switch self {
     case .some(let y):
-      return .some(try f(y))
+      return .some(try transform(y))
     case .none:
       return .none
     }
@@ -180,13 +183,16 @@ public enum Optional<Wrapped> : NilLiteralConvertible {
   ///     print(nonOverflowingSquare)
   ///     // Prints "Optional(1746)"
   ///
-  /// - Parameter f: A closure that takes the unwrapped value of the instance.
+  /// - Parameter transform: A closure that takes the unwrapped value
+  ///   of the instance.  
   /// - Returns: The result of the given closure. If this instance is `nil`,
   ///   returns `nil`.
-  public func flatMap<U>(_ f: @noescape (Wrapped) throws -> U?) rethrows -> U? {
+  public func flatMap<U>(
+    _ transform: @noescape (Wrapped) throws -> U?
+  ) rethrows -> U? {
     switch self {
     case .some(let y):
-      return try f(y)
+      return try transform(y)
     case .none:
       return .none
     }

test/Prototypes/CollectionTransformers.swift

@@ -853,7 +853,7 @@ internal class _CollectionTransformerStep<PipelineInputElement_, OutputElement_>
   typealias PipelineInputElement = PipelineInputElement_
   typealias OutputElement = OutputElement_
 
-  func map<U>(_ elementTransform: (OutputElement) -> U)
+  func map<U>(_ transform: (OutputElement) -> U)
     -> _CollectionTransformerStep<PipelineInputElement, U> {
 
     fatalError("abstract method")