From 092087fc540337ff964d76885d823d3a6a5a9c58 Mon Sep 17 00:00:00 2001
From: Rob Rix <rob.rix@github.com>
Date: Tue, 6 Oct 2015 14:15:21 -0400
Subject: [PATCH] Extract row-major ordering into a private function.

---
 prototype/Doubt/Matrix.swift | 22 ++++++++++++----------
 1 file changed, 12 insertions(+), 10 deletions(-)

diff --git a/prototype/Doubt/Matrix.swift b/prototype/Doubt/Matrix.swift
index b87029f77..c983aaf97 100644
--- a/prototype/Doubt/Matrix.swift
+++ b/prototype/Doubt/Matrix.swift
@@ -5,16 +5,7 @@
 /// Values are retrieved by subscripting with row/column indices. Out-of-bound indices produce `nil` values, rather than asserting.
 public struct Matrix<A> {
 	public init(width: Int, height: Int, compute: (Int, Int) -> A) {
-		var values: [Memo<A>] = []
-		values.reserveCapacity(width * height)
-
-		for j in 0..<height {
-			for i in 0..<width {
-				values.append(Memo<A> { compute(i, j) })
-			}
-		}
-
-		self.init(width: width, height: height, values: values)
+		self.init(width: width, height: height, values: constructRowMajor(width, height: height, forEach: compute >>> Memo.init))
 	}
 
 	public let width: Int
@@ -43,3 +34,14 @@ public struct Matrix<A> {
 		self.values = values
 	}
 }
+
+private func constructRowMajor<A>(width: Int, height: Int, @noescape forEach: (Int, Int) -> A) -> [A] {
+	var values: [A] = []
+	values.reserveCapacity(width * height)
+	for j in 0..<height {
+		for i in 0..<width {
+			values.append(forEach(i, j))
+		}
+	}
+	return values
+}