Enhances join filter for natural language join (i.e., \"A, B and C\")

doc/filters/join.rst

@@ -16,8 +16,17 @@ define it with the optional first parameter:
 
     {{ [1, 2, 3]|join('|') }}
     {# outputs 1|2|3 #}
+    
+A second parameter can also be provided that will be the separator used
+between the last two items of the sequence:
 
+.. code-block:: jinja
+
+    {{ [1, 2, 3]|join(', ', ' and ') }}
+    {# outputs 1, 2 and 3 #}
+    
 Arguments
 ---------
 
 * ``glue``: The separator
+* ``and``: The separator for the last pair of input items

lib/Twig/Extension/Core.php

@@ -717,9 +717,12 @@ function twig_last(Twig_Environment $env, $item)
 /**
  * Joins the values to a string.
  *
- * The separator between elements is an empty string per default, you can define it with the optional parameter.
+ * The separators between elements are empty strings per default, you can define them with the optional parameters.
  *
  * <pre>
+ *  {{ [1, 2, 3]|join(', ', ' and ') }}
+ *  {# returns 1, 2 and 3 #}
+ *
  *  {{ [1, 2, 3]|join('|') }}
  *  {# returns 1|2|3 #}
  *
@@ -727,18 +730,29 @@ function twig_last(Twig_Environment $env, $item)
  *  {# returns 123 #}
  * </pre>
  *
- * @param array  $value An array
- * @param string $glue  The separator
+ * @param array       $value An array
+ * @param string      $glue  The separator
+ * @param string|null $and   The separator for the last pair
  *
  * @return string The concatenated string
  */
-function twig_join_filter($value, $glue = '')
+function twig_join_filter($value, $glue = '', $and = null)
 {
     if ($value instanceof Traversable) {
         $value = iterator_to_array($value, false);
+    } else {
+        $value = (array) $value;
     }
 
-    return implode($glue, (array) $value);
+    if (empty( $value ) || null === $and || $and === $glue) {
+        return implode($glue, $value);
+    }
+    $last = array_values( array_slice( $value, -1 ) )[0];
+    $value = array_slice( $value, 0, -1 );
+    if( $value ) {
+        return implode($glue, $value) . $and . $last;
+    }
+    return $last;
 }
 
 /**

test/Twig/Tests/Fixtures/filters/join.test

@@ -4,9 +4,35 @@
 {{ ["foo", "bar"]|join(', ') }}
 {{ foo|join(', ') }}
 {{ bar|join(', ') }}
+
+{{ ["foo", "bar"]|join(', ', ' and ') }}
+{{ foo|join(', ', ' and ') }}
+{{ bar|join(', ', ' and ') }}
+{{ ["one", "two", "three"]|join(', ', ' and ') }}
+{{ ["a", "b", "c"]|join('','-') }}
+{{ ["a", "b", "c"]|join('-','-') }}
+{{ ["a", "b", "c"]|join('-','') }}
+{{ ["hello"]|join('|','-') }}
+
+{{ {"a": "w", "b": "x", "c": "y", "d": "z"}|join }}
+{{ {"a": "w", "b": "x", "c": "y", "d": "z"}|join(',') }}
+{{ {"a": "w", "b": "x", "c": "y", "d": "z"}|join(',','-') }}
 --DATA--
 return array('foo' => new TwigTestFoo(), 'bar' => new ArrayObject(array(3, 4)))
 --EXPECT--
 foo, bar
 1, 2
 3, 4
+
+foo and bar
+1 and 2
+3 and 4
+one, two and three
+ab-c
+a-b-c
+a-bc
+hello
+
+wxyz
+w,x,y,z
+w,x,y-z