added the range filter

git-svn-id: http://svn.twig-project.org/trunk@171 93ef8e89-cb99-4229-a87c-7fa0fa45744b

CHANGELOG

@@ -1,7 +1,7 @@
 * 0.9.5-DEV
 
  * added the in operator (as a syntactic sugar for the in filter)
- * added the following filters in the Core extension: in
+ * added the following filters in the Core extension: in, range
  * added support for arrays (same behavior as in PHP, a mix between lists and dictionaries, arrays and hashes)
  * enhanced some error messages to provide better feedback in case of parsing errors
 

doc/02-Twig-for-Template-Designers.markdown

@@ -395,6 +395,17 @@ provided in a variable called `users`:
 >A sequence can be either an array or an object implementing the `Iterator`
 >interface.
 
+If you do need to iterate over a sequence of numbers, you can use the `range`
+filter:
+
+    [twig]
+    {% for i in 0|range(10) %}
+      * {{ i }}
+    {% endfor %}
+
+The above snippet of code would print all numbers from 0 to 9 (the high value
+is never part of the generated array).
+
 Inside of a `for` loop block you can access some special variables:
 
 | Variable              | Description
@@ -864,6 +875,23 @@ The `in` operator is a syntactic sugar for the `in` filter:
       TRUE
     {% endif %}
 
+### `range`
+
+Returns a list containing a sequence of numbers. The filtered value represents
+the low value and the filter takes two arguments: the first one is mandatory
+are represents the high value, and the second one is optional and represents
+the step (which defaults to `1`).
+
+If you do need to iterate over a sequence of numbers:
+
+    [twig]
+    {% for i in 0|range(10) %}
+      * {{ i }}
+    {% endfor %}
+
+>**TIP**
+>The `range` filter works as the native PHP `range` function.
+
 ### `default`
 
 The `default` filter returns the passed default value if the value is

lib/Twig/Extension/Core.php

@@ -85,6 +85,7 @@ class Twig_Extension_Core extends Twig_Extension
       'length'  => array('twig_length_filter', false),
       'sort'    => array('twig_sort_filter', false),
       'in'      => array('twig_in_filter', false),
+      'range'   => array('twig_range_filter', false),
 
       // iteration and runtime
       'default' => array('twig_default_filter', false),

lib/Twig/runtime.php

@@ -105,6 +105,11 @@ function twig_in_filter($value, $compare)
   return false;
 }
 
+function twig_range_filter($start, $end, $step = 1)
+{
+  return range($start, $end, $step);
+}
+
 /*
  * Each type specifies a way for applying a transformation to a string
  * The purpose is for the string to be "escaped" so it is suitable for