update the Docstring of do_truncate, add useful examples

diff --git a/jinja2/filters.py b/jinja2/filters.py
index 8fef6eaa322b94f68e07a9c177b1cc4eea159eda..b4152f76f9885c050d958ceae02fc2a60f6c8620 100644 (file)
--- a/jinja2/filters.py
+++ b/jinja2/filters.py
@@ -443,16 +443,17 @@ def do_truncate(s, length=255, killwords=False, end='...'):
     """Return a truncated copy of the string. The length is specified
     with the first parameter which defaults to ``255``. If the second
     parameter is ``true`` the filter will cut the text at length. Otherwise
-    it will try to save the last word. If the text was in fact
+    it will discard the last word. If the text was in fact
     truncated it will append an ellipsis sign (``"..."``). If you want a
     different ellipsis sign than ``"..."`` you can specify it using the
     third parameter.
 
-    .. sourcecode jinja::
+    .. sourcecode:: jinja
 
-        {{ mytext|truncate(300, false, '»') }}
-            truncate mytext to 300 chars, don't split up words, use a
-            right pointing double arrow as ellipsis sign.
+        {{ "foo bar"|truncate(5) }}
+            -> "foo ..."
+        {{ "foo bar"|truncate(5, True) }}
+            -> "foo b..."
     """
     if len(s) <= length:
         return s