[SE-0046] Implements consistent function parameter labels by discarding extraneous parameter names and adding _ where necessary

Author: manavgabhawala

CHANGELOG.md

@@ -3,6 +3,26 @@ Note: This is in reverse chronological order, so newer entries are added to the
 Swift 3.0
 -------
 
+* [SE-0046] (https://github.com/apple/swift-evolution/blob/master/proposals/0046-first-label.md) Function parameters now have consistent labelling across all function parameters. With this update the first parameter declarations will now match the existing behavior of the second and later parameters. This change makes the language simpler. 
+
+    Functions that were written and called as follows 
+    ```swift
+      func foo(x: Int, y: Int) {
+      }
+      foo(1, y: 2)
+      
+      func bar(a a: Int, b: Int) {
+      } 
+      bar(a: 3, b: 4)
+    ```
+    will now be written as (to achieve the same behavior):
+    ```swift
+        func foo(_ x: Int, y: Int) {}
+        foo(1, y: 2)
+        func bar(a: Int, b: Int) {} 
+        bar(a: 3, b: 4)
+    ```
+
 * [SE-0037](https://github.com/apple/swift-evolution/blob/master/proposals/0037-clarify-comments-and-operators.md)
   Comments are now treated as whitespace when determining whether an operator is
   prefix, postfix, or binary. For example, these now work:

benchmark/single-source/Ackermann.swift

@@ -14,14 +14,14 @@
 // for performance measuring.
 import TestsUtils
 
-func ackermann(M : Int, _ N : Int) -> Int {
+func ackermann(_ M: Int, _ N : Int) -> Int {
   if (M == 0) { return N + 1 }
   if (N == 0) { return ackermann(M - 1, 1) }
   return ackermann(M - 1, ackermann(M, N - 1))
 }
 
 @inline(never)
-func Ackermann(M : Int, _ N : Int) -> Int {
+func Ackermann(_ M: Int, _ N : Int) -> Int {
   // This if prevents optimizer from computing return value of Ackermann(3,9)
   // at compile time.
   if False() { return 0 }
@@ -33,7 +33,7 @@ func Ackermann(M : Int, _ N : Int) -> Int {
 let ref_result = [5, 13, 29, 61, 125, 253, 509, 1021, 2045, 4093, 8189, 16381, 32765, 65533, 131069];
 
 @inline(never)
-public func run_Ackermann(N: Int) {
+public func run_Ackermann(_ N: Int) {
   let (m, n) = (3, 9)
   var result = 0
   for _ in 1...N {

benchmark/single-source/AngryPhonebook.swift

@@ -31,7 +31,7 @@ var words = [
   "Bobby", "Dylan", "Johnny", "Phillip", "Craig"]
 
 @inline(never)
-public func run_AngryPhonebook(N: Int) {
+public func run_AngryPhonebook(_ N: Int) {
   // Permute the names.
   for _ in 1...N {
     for firstname in words {

benchmark/single-source/Array2D.swift

@@ -11,7 +11,7 @@
 //===----------------------------------------------------------------------===//
 
 @inline(never)
-public func run_Array2D(N: Int) {
+public func run_Array2D(_ N: Int) {
   var A: [[Int]] = []
   for _ in 0 ..< 1024 {
     var B: [Int] = []

benchmark/single-source/ArrayAppend.swift

@@ -15,7 +15,7 @@
 import TestsUtils
 
 @inline(never)
-public func run_ArrayAppend(N: Int) {
+public func run_ArrayAppend(_ N: Int) {
   for _ in 0..<N {
     for _ in 0..<10 {
        var nums = [Int]()
@@ -27,7 +27,7 @@ public func run_ArrayAppend(N: Int) {
 }
 
 @inline(never)
-public func run_ArrayAppendReserved(N: Int) {
+public func run_ArrayAppendReserved(_ N: Int) {
   for _ in 0..<N {
     for _ in 0..<10 {
        var nums = [Int]()

benchmark/single-source/ArrayInClass.swift

@@ -17,7 +17,7 @@ class ArrayContainer {
     arr = [Int] (repeating: 0, count: 100_000)
   }
 
-  func runLoop(N: Int) {
+  func runLoop(_ N: Int) {
     for _ in 0 ..< N {
       for i in 0 ..< arr.count {
         arr[i] = arr[i] + 1
@@ -32,7 +32,7 @@ func getArrayContainer() -> ArrayContainer {
 }
 
 @inline(never)
-public func run_ArrayInClass(N: Int) {
+public func run_ArrayInClass(_ N: Int) {
   let a = getArrayContainer()
   a.runLoop(N)
 }

benchmark/single-source/ArrayLiteral.swift

@@ -21,7 +21,7 @@ func makeArray() -> [Int] {
 }
 
 @inline(never)
-public func run_ArrayLiteral(N: Int) {
+public func run_ArrayLiteral(_ N: Int) {
   for _ in 1...10000*N {
     makeArray()
   }
@@ -34,7 +34,7 @@ func addLiteralArray() -> Int {
 }
 
 @inline(never)
-public func run_ArrayValueProp(N: Int) {
+public func run_ArrayValueProp(_ N: Int) {
   var res = 123
   for _ in 1...10000*N {
     res += addLiteralArray()
@@ -75,7 +75,7 @@ func addLiteralArray4() -> Int {
 }
 
 @inline(never)
-public func run_ArrayValueProp2(N: Int) {
+public func run_ArrayValueProp2(_ N: Int) {
   var res = 123
   for _ in 1...10000*N {
     res += addLiteralArray2()
@@ -85,7 +85,7 @@ public func run_ArrayValueProp2(N: Int) {
 }
 
 @inline(never)
-public func run_ArrayValueProp3(N: Int) {
+public func run_ArrayValueProp3(_ N: Int) {
   var res = 123
   for _ in 1...10000*N {
     res += addLiteralArray3()
@@ -95,7 +95,7 @@ public func run_ArrayValueProp3(N: Int) {
 }
 
 @inline(never)
-public func run_ArrayValueProp4(N: Int) {
+public func run_ArrayValueProp4(_ N: Int) {
   var res = 123
   for _ in 1...10000*N {
     res += addLiteralArray4()

benchmark/single-source/ArrayOfGenericPOD.swift

@@ -58,7 +58,7 @@ func genStructArray() {
 }
 
 @inline(never)
-public func run_ArrayOfGenericPOD(N: Int) {
+public func run_ArrayOfGenericPOD(_ N: Int) {
   for _ in 0...N {
     genEnumArray()
     genIOUArray()

benchmark/single-source/ArrayOfGenericRef.swift

@@ -86,7 +86,7 @@ func genRefStructArray() {
 }
 
 @inline(never)
-public func run_ArrayOfGenericRef(N: Int) {
+public func run_ArrayOfGenericRef(_ N: Int) {
   for _ in 0...N {
     genPODRefArray()
     genCommonRefArray()

benchmark/single-source/ArrayOfPOD.swift

@@ -53,7 +53,7 @@ func genStructArray() {
 }
 
 @inline(never)
-public func run_ArrayOfPOD(N: Int) {
+public func run_ArrayOfPOD(_ N: Int) {
   for _ in 0...N {
     genIntArray()
     genEnumArray()