Move shiftUp function to Custom Expression class.

Author: Jason Machado Silva

Tools/Evaluator/CustomExpressionLanguageProvider.php

@@ -29,6 +29,7 @@ public function getFunctions()
             $this->createStrtoupperFunction(),
             $this->createGetKeyFunction(),
             $this->createGetValueFunction(),
+            $this->createShiftUpFunction()
         ];
     }
 
@@ -405,4 +406,27 @@ function ($arguments, $array) {
             }
         );
     }
+
+    /**
+     * @param array $elements
+     *
+     * @return array
+     */
+    protected function createShiftUpFunction()
+    {
+        return new ExpressionFunction(
+            'shiftUp',
+            function($array) {
+                return sprintf('shiftUp(%s)', $array);
+            },
+            function ($arguments, $array) {
+                if (!is_array($array)) {
+                    throw new \RuntimeException('Argument passed to "shiftUp" should be an array.');
+                }
+
+                return array_merge(...$array);
+            }
+        );
+
+    }
 }

Tools/Mapper/Mapper.php

@@ -194,16 +194,6 @@ public function first(array $array)
         return reset($array);
     }
 
-    /**
-     * @param array $elements
-     *
-     * @return array
-     */
-    public function shiftUp(array $elements)
-    {
-        return array_merge(...$elements);
-    }
-
     /**
      * Convert a string to date.
      *