From c8382fab8da3bb6d89e37d0a9bf1597acf9c35a2 Mon Sep 17 00:00:00 2001
From: Rahul Kadyan <hi@znck.me>
Date: Sat, 10 Oct 2015 23:08:09 +0530
Subject: [PATCH] Merge pull request #24 from znck:master

Fixes #21: Immutable array could be modified with some methods
---
 src/ImmutableArray.php       | 58 ++++++++++++++++++++++++++++++++++++
 tests/ImmutableArrayTest.php | 10 ++++---
 2 files changed, 64 insertions(+), 4 deletions(-)

diff --git a/src/ImmutableArray.php b/src/ImmutableArray.php
index 2c51baa..9464fae 100644
--- a/src/ImmutableArray.php
+++ b/src/ImmutableArray.php
@@ -127,6 +127,35 @@ public function mergeTo(array $array, $recursively = false)
         return new static(array_merge($array, $this->elements));
     }
 
+    /**
+     * Push one or more values onto the end of array at once.
+     *
+     * @param mixed $element The pushed element
+     * @param mixed $_ [optional] Multiple arguments allowed
+     *
+     * @return static The new instance with pushed elements to the end of array
+     */
+    public function push($element, $_ = null)
+    {
+        $elements = $this->elements;
+        if (func_num_args()) {
+            $args = array_merge([&$elements], func_get_args());
+            call_user_func_array('array_push', $args);
+        }
+
+        return new static($elements);
+    }
+
+    /**
+     * Pop a specified value off the end of array.
+     *
+     * @return mixed The popped element
+     */
+    public function pop()
+    {
+        return $this->count() ? $this->last() : null;
+    }
+
     /**
      * Replace array with given one
      *
@@ -197,6 +226,35 @@ public function diffWith(array $array)
         return new static(array_diff($this->elements, $array));
     }
 
+    /**
+     * Unshift array
+     *
+     * @param mixed $element The element for prepend
+     * @param mixed $_ [optional] Multiple arguments allowed
+     *
+     * @return static The new instance with prepended elements to the beginning of array
+     */
+    public function unshift($element, $_ = null)
+    {
+        $elements = $this->elements;
+        if (func_num_args()) {
+            $args = array_merge([&$elements], func_get_args());
+            call_user_func_array('array_unshift', $args);
+        }
+
+        return new static($elements);
+    }
+
+    /**
+     * Shifts a specified value off the beginning of array.
+     *
+     * @return mixed The shifted element
+     */
+    public function shift()
+    {
+        return $this->count() ? $this->first() : null;
+    }
+
     /**
      * Shuffle array
      *
diff --git a/tests/ImmutableArrayTest.php b/tests/ImmutableArrayTest.php
index 40b5ba6..09f385b 100644
--- a/tests/ImmutableArrayTest.php
+++ b/tests/ImmutableArrayTest.php
@@ -557,10 +557,11 @@ public function testReduce(array $array)
     public function testShift(array $array)
     {
         $ma = new ImmutableArray($array);
+        $copyMa = new ImmutableArray($array);
         $shiftedValue = $ma->shift();
         $shiftedArrayValue = array_shift($array);
 
-        $this->assertTrue($array === $ma->toArray());
+        $this->assertTrue($copyMa->toArray() === $ma->toArray());
         $this->assertTrue($shiftedArrayValue === $shiftedValue);
     }
 
@@ -575,7 +576,7 @@ public function testUnshift(array $array)
         $copiedMa = $ma->unshift($newElement1, $newElement2);
         array_unshift($array, $newElement1, $newElement2);
 
-        $this->assertTrue($copiedMa === $ma);
+        $this->assertTrue($copiedMa->toArray() !== $ma->toArray());
         $this->assertTrue($array === $copiedMa->toArray());
     }
 
@@ -585,10 +586,11 @@ public function testUnshift(array $array)
     public function testPop(array $array)
     {
         $ma = new ImmutableArray($array);
+        $copyMa = new ImmutableArray($array);
         $poppedValue = $ma->pop();
         $poppedArrayValue = array_pop($array);
 
-        $this->assertTrue($array === $ma->toArray());
+        $this->assertTrue($copyMa->toArray() === $ma->toArray());
         $this->assertTrue($poppedArrayValue === $poppedValue);
     }
 
@@ -603,7 +605,7 @@ public function testPush(array $array)
         $copiedMa = $ma->push($newElement1, $newElement2);
         array_push($array, $newElement1, $newElement2);
 
-        $this->assertTrue($copiedMa === $ma);
+        $this->assertTrue($copiedMa->toArray() !== $ma->toArray());
         $this->assertTrue($array === $copiedMa->toArray());
     }