Math\{maxv, minv}

Summary:
This introduces `Math\{maxv, minv}` and aliases `Math\{max, min}` to them for migration purposes. The intended end state is that `C\{max, min}` are moved into the Math namespaces to become `Math\{max, min}`.

See #25.

Reviewed By: fredemmott

Differential Revision: D6095022

fbshipit-source-id: d1199d2d4f4a2d0cdbfe552679b833c50b7ac13b

src/math/compare.php

@@ -0,0 +1,44 @@
+<?hh // strict
+/*
+ *  Copyright (c) 2004-present, Facebook, Inc.
+ *  All rights reserved.
+ *
+ *  This source code is licensed under the BSD-style license found in the
+ *  LICENSE file in the root directory of this source tree. An additional grant
+ *  of patent rights can be found in the PATENTS file in the same directory.
+ *
+ */
+
+namespace HH\Lib\Math;
+
+/**
+ * Returns the largest of all input numbers.
+ *
+ * To find the smallest number, see `Math\min`.
+ * For Traversables, see `C\max`.
+ */
+function maxv<T as num>(T $first, T ...$rest): T {
+  $max = $first;
+  foreach ($rest as $number) {
+    if ($number > $max) {
+      $max = $number;
+    }
+  }
+  return $max;
+}
+
+/**
+ * Returns the smallest of all input numbers.
+ *
+ * To find the largest number, see `Math\max`.
+ * For Traversables, see `C\min`.
+ */
+function minv<T as num>(T $first, T ...$rest): T {
+  $min = $first;
+  foreach ($rest as $number) {
+    if ($number < $min) {
+      $min = $number;
+    }
+  }
+  return $min;
+}

src/math/containers.php

@@ -19,13 +19,7 @@
  * For Traversables, see `C\max`.
  */
 function max<T as num>(T $first_number, T ...$numbers): T {
-  $max = $first_number;
-  foreach ($numbers as $number) {
-    if ($number > $max) {
-      $max = $number;
-    }
-  }
-  return $max;
+  return namespace\maxv($first_number, ...$numbers);
 }
 
 /**
@@ -55,7 +49,6 @@ function mean(Container<num> $numbers): ?float {
  */
 function median(Container<num> $numbers): ?float {
   $numbers = Vec\sort($numbers);
-
   $count = C\count($numbers);
   if ($count === 0) {
     return null;
@@ -76,13 +69,7 @@ function median(Container<num> $numbers): ?float {
  * For Traversables, see `C\min`.
  */
 function min<T as num>(T $first_number, T ...$numbers): T {
-  $min = $first_number;
-  foreach ($numbers as $number) {
-    if ($number < $min) {
-      $min = $number;
-    }
-  }
-  return $min;
+  return namespace\minv($first_number, ...$numbers);
 }
 
 /**

tests/math/MathCompareTest.php

@@ -0,0 +1,67 @@
+<?hh // strict
+/*
+ *  Copyright (c) 2004-present, Facebook, Inc.
+ *  All rights reserved.
+ *
+ *  This source code is licensed under the BSD-style license found in the
+ *  LICENSE file in the root directory of this source tree. An additional grant
+ *  of patent rights can be found in the PATENTS file in the same directory.
+ *
+ */
+
+use namespace HH\Lib\Math;
+use function Facebook\FBExpect\expect;
+
+/**
+ * @emails oncall+hack_prod_infra
+ */
+final class MathCompareTest extends PHPUnit_Framework_TestCase {
+
+  public static function provideTestMaxv(): array<mixed> {
+    return array(
+      tuple(1, vec[2], 2),
+      tuple(2, vec[1], 2),
+      tuple(1.0, vec[2.0], 2.0),
+      tuple(2.0, vec[1.0], 2.0),
+      tuple(1, vec[1], 1),
+      tuple(-2, vec[-1], -1),
+      tuple(1.0, vec[2], 2),
+      tuple(1, vec[2.0], 2.0),
+      tuple(-1, vec[1, 2, 3, 4, 5], 5),
+      tuple(-1, vec[5, 4, 3, 2, 1], 5),
+    );
+  }
+
+  /** @dataProvider provideTestMaxv */
+  public function testMaxv<T as num>(
+    T $first,
+    Container<T> $rest,
+    T $expected,
+  ): void {
+    expect(Math\maxv($first, ...$rest))->toBeSame($expected);
+  }
+
+  public static function provideTestMinv(): array<mixed> {
+    return array(
+      tuple(1, vec[2], 1),
+      tuple(2, vec[1], 1),
+      tuple(1.0, vec[2.0], 1.0),
+      tuple(2.0, vec[1.0], 1.0),
+      tuple(1, vec[1], 1),
+      tuple(-2, vec[-1], -2),
+      tuple(1.0, vec[2], 1.0),
+      tuple(1, vec[2.0], 1),
+      tuple(1, vec[-1, -2, -3, -4, -5], -5),
+      tuple(1, vec[-5, -4, -3, -2, -1], -5),
+    );
+  }
+
+  /** @dataProvider provideTestMinv */
+  public function testMinv<T as num>(
+    T $first,
+    Container<T> $rest,
+    T $expected,
+  ): void {
+    expect(Math\minv($first, ...$rest))->toBeSame($expected);
+  }
+}