Added top and islice filters

hyde/ext/templates/jinja.py

@@ -5,6 +5,7 @@ Jinja template utilties
 
 from datetime import datetime, date
 import re
+import itertools
 
 from hyde.fs import File, Folder
 from hyde.model import Expando
@@ -67,6 +68,12 @@ def date_format(ctx, dt, fmt=None):
     return dt.strftime(format)
 
 
+def islice(iterable, start=0, stop=3, step=1):
+    return itertools.islice(iterable, start, stop, step)
+
+def top(iterable, count=3):
+    return islice(iterable, stop=count)
+
 def xmldatetime(dt):
     if not dt:
         dt = datetime.now()
@@ -555,6 +562,8 @@ class Jinja2Template(Template):
         self.env.filters['syntax'] = syntax
         self.env.filters['date_format'] = date_format
         self.env.filters['xmldatetime'] = xmldatetime
+        self.env.filters['islice'] = islice
+        self.env.filters['top'] = top
 
         config = {}
         if hasattr(site, 'config'):

hyde/tests/test_jinja2template.py

@@ -523,4 +523,39 @@ two:
         assert ones == ["A", "B", "C"]
 
         twos = [item.text for item in actual("ul.two li")]
-        assert twos == ["D", "E", "F"]
+        assert twos == ["D", "E", "F"]
+
+    def test_top_filter(self):
+
+        text = """
+{% yaml test %}
+item_list:
+    - A
+    - B
+    - C
+    - D
+    - E
+    - F
+{% endyaml %}
+<ul class="top">
+{% for value in test.item_list|top(3) %}
+    <li>{{ value }}</li>
+{% endfor %}
+</ul>
+<ul class="mid">
+{% for value in test.item_list|islice(3, 6) %}
+    <li>{{ value }}</li>
+{% endfor %}
+</ul>
+"""
+        t = Jinja2Template(JINJA2.path)
+        t.configure(None)
+        html = t.render(text, {}).strip()
+        print html
+        actual = PyQuery(html)
+        assert actual("ul").length == 2
+        assert actual("li").length == 6
+        items = [item.text for item in actual("ul.top li")]
+        assert items == ["A", "B", "C"]
+        items = [item.text for item in actual("ul.mid li")]
+        assert items == ["D", "E", "F"]