first attempt at a single/multi-column toggle for folder contents

substanced/folder/templates/contents.pt

@@ -40,24 +40,56 @@
           -- all --
         </label>
 
-        <div id="choices">
-
-          <tal:loop tal:repeat="choice batch.items">
-            <tal:block condition="choice['viewable']">
-              <label class="checkbox" for="delete-${repeat.choice.index}">
-                <i class="${choice['icon']}"> </i>
-                <input tal:attributes="disabled not choice['deletable']"
-                       type="checkbox"
-                       name="delete"
-                       value="${choice['name']}"
-                       id="delete-${repeat.choice.index}"/>
-                <a href="${choice['url']}">${choice['name']}</a>
-              </label>
-            </tal:block>
-          </tal:loop>
+        <div id="choices" class="row" tal:condition="not batch.multicolumn">
+
+          <div class="span3">
+            <tal:loop tal:repeat="choice batch.items">
+              <tal:block condition="choice['viewable']">
+                <label class="checkbox" for="delete-${repeat.choice.index}">
+                  <i class="${choice['icon']}"> </i>
+                  <input tal:attributes="disabled not choice['deletable']"
+                         type="checkbox"
+                         name="delete"
+                         value="${choice['name']}"
+                         id="delete-${repeat.choice.index}"/>
+                  <a href="${choice['url']}">${choice['name']}</a>
+                </label>
+              </tal:block>
+            </tal:loop>
+          </div>
 
         </div>
 
+        <div id="choices" tal:condition="batch.multicolumn">
+
+          <div class="row-fluid" tal:define="position 0">
+            <tal:loop tal:repeat="column batch.make_columns()">
+              <div class="span3">
+                <tal:loop tal:repeat="choice column">
+                  <tal:block condition="choice['viewable']">
+                    <label class="checkbox" for="delete-${position}">
+                      <i class="${choice['icon']}"> </i>
+                      <input tal:attributes="disabled not choice['deletable']"
+                             type="checkbox"
+                             name="delete"
+                             value="${choice['name']}"
+                             id="delete-${position}"/>
+                      <a href="${choice['url']}">${choice['name']}</a>
+                    </label>
+                  </tal:block>
+                  <?python position += 1 ?>
+                </tal:loop>
+              </div>
+            </tal:loop>
+          </div>
+        </div>
+
+      </div>
+
+      <div class="row-fluid" tal:condition="batch.required">
+        <div class="span2">
+          <a class="btn" href="${batch.toggle_url}">${batch.toggle_text}</a>
+        </div>
       </div>
 
       <input type="hidden" name="csrf_token" 
@@ -85,7 +117,6 @@
           </ul>
         </div>
       </div>
-
       </fieldset>
      </form>
 

substanced/util/__init__.py

@@ -142,10 +142,31 @@ class Batch(object):
       ``True`` if either ``next_url`` or ``prev_url`` are ``True`` (meaning
       batching is required).
 
+    ``multicolumn``
+
+      ``True`` if the current view should be rendered in multiple columns.
+
+    ``toggle_url``
+
+      The URL to be used for the multicolumn/single column toggle button. The
+      ``batch_size``, ``batch_num``, and ``multicolumn`` parameters are
+      converted to their multicolumn or single column equivalents. If a user
+      is viewing items 40-80 in multiple columns, the toggle will switch to
+      items 40-50 in a single column. If a user is viewing items 50-60 in a
+      single column, the toggle will switch to items 40-80 in multiple columns.
+
+    ``toggle_text``
+
+      The text to display on the multi-column/single column toggle.
+
     The ``seq`` passed must define ``__len__`` and ``__slice__`` methods.
+
+    ``make_columns``
+
+    A method to split ``items`` into a nested list representing columns.
 
     """
-    def __init__(self, seq, request, url=None, default_size=15):
+    def __init__(self, seq, request, url=None, default_size=10, toggle_size=40):
         if url is None:
             url = request.url
 
@@ -163,6 +184,17 @@ def __init__(self, seq, request, url=None, default_size=15):
         if size < 1:
             size = default_size
 
+        multicolumn = request.params.get('multicolumn', '') == 'True'
+
+        # create multicolumn/single column toggle attributes
+        if multicolumn:
+            toggle_num = size * num / default_size
+            toggle_size = default_size
+            toggle_text = 'Single column'
+        else:
+            toggle_num = size * num / toggle_size
+            toggle_text = 'Multi-column'
+
         start = num * size
         end = start + size
         items = seq[start:end]
@@ -173,6 +205,7 @@ def __init__(self, seq, request, url=None, default_size=15):
         prev_url = None
         next_url = None
         last_url = None
+        toggle_url = None
 
         if num:
             first_url = merge_url_qs(url, batch_size=size, batch_num=0)
@@ -183,17 +216,38 @@ def __init__(self, seq, request, url=None, default_size=15):
         if size and (num < last):
             last_url = merge_url_qs(url, batch_size=size, batch_num=last)
 
+        if prev_url or next_url:
+            toggle_url = merge_url_qs(
+                url,
+                batch_size=toggle_size,
+                batch_num=toggle_num,
+                multicolumn=not multicolumn,
+                )
+
         self.items = items
         self.num = num
         self.size = size
         self.length = length
         self.required = bool(prev_url or next_url)
+        self.multicolumn = multicolumn
+        self.toggle_url = toggle_url
+        self.toggle_text = toggle_text
         self.first_url = first_url
         self.prev_url = prev_url
         self.next_url = next_url
         self.last_url = last_url
         self.last = last
 
+    def make_columns(self, column_size=10, num_columns=4):
+        """ Break ``self.items`` into a nested list representing columns."""
+        columns = []
+        for i in range(num_columns):
+            start = i * column_size
+            end = start + column_size
+            part = self.items[start:end]
+            columns.append(part)
+        return columns
+
 def chunks(stream, chunk_size=10000):
     """ Return a generator that will iterate over a stream (a filelike
     object) ``chunk_size`` bytes at a time."""

substanced/util/tests.py

@@ -183,6 +183,28 @@ def test_it_size_zero(self):
         self.assertEqual(inst.items, seq)
         self.assertEqual(inst.size, 15)
 
+    def test_it_multicolumn_toggle_text(self):
+        seq = [1,2,3,4,5,6]
+        request = testing.DummyRequest()
+        request.params['multicolumn'] = 'True'
+        inst = self._makeOne(seq, request)
+        self.assertEqual(inst.toggle_text, 'Single column')
+
+    def test_it_not_multicolumn_toggle_text(self):
+        seq = [1,2,3,4,5,6]
+        request = testing.DummyRequest()
+        request.params['multicolumn'] = 'False'
+        inst = self._makeOne(seq, request)
+        self.assertEqual(inst.toggle_text, 'Multi-column')
+
+    def test_it_make_columns(self):
+        seq = [1,2,3,4,5,6]
+        request = testing.DummyRequest()
+        inst = self._makeOne(seq, request)
+        cols = inst.make_columns(column_size=2, num_columns=3)
+        expected = [ [1,2], [3,4], [5,6] ]
+        self.assertEqual(cols, expected)
+
 class Test_merge_url_qs(unittest.TestCase):
     def _callFUT(self, url, **kw):
         from . import merge_url_qs