added a LinkWidget as well as docs and tests

docs/ref/filters.txt

@@ -86,7 +86,11 @@ argument.
 ``widget``
 ~~~~~~~~~~
 
-The django.form Widget class which will represent the ``Filter``.
+The django.form Widget class which will represent the ``Filter``.  In addition 
+to the widgets that are included with Django that you can use there are 
+additional ones that django-filte provides which may be useful:
+    * ``filter.widgets.LinkWidget`` -- this displays the options in a mannner 
+      similar to the way the Django Admin does, as a series of links.
 
 ``action``
 ~~~~~~~~~~

filter/tests.py

@@ -3,6 +3,7 @@
 >>> from django.core.management import call_command
 >>> import filter
 >>> from filter import FilterSet
+>>> from filter.widgets import LinkWidget
 >>> from filter.models import User, Comment, Book, STATUS_CHOICES
 
 >>> call_command('loaddata', 'test_data', verbosity=0)
@@ -275,5 +276,27 @@
 >>> f= F({'price_0': '15', 'price_1': 'lt'})
 >>> f.qs
 [<Book: Ender's Game>]
+>>> class F(FilterSet):
+...     status = filter.ChoiceFilter(widget=LinkWidget, choices=STATUS_CHOICES)
+...     class Meta:
+...         model = User
+...         fields = ['status']
+>>> f = F()
+>>> f.qs
+[<User: alex>, <User: aaron>, <User: jacob>]
+>>> print f.form
+<tr><th><label for="id_status">Status:</label></th><td><ul id="id_status">
+<a href="?status=0">Regular</a>
+<a href="?status=1">Admin</a>
+</ul></td></tr>
+>>> f = F({'status': '1'})
+>>> f.qs
+[<User: alex>]
+>>> print f.form
+<tr><th><label for="id_status">Status:</label></th><td><ul id="id_status">
+<a href="?status=0">Regular</a>
+<a href="?status=1">Admin</a>
+</ul></td></tr>
+
 """}
 

filter/widgets.py

@@ -1,4 +1,52 @@
+from itertools import chain
+from urllib import urlencode
+
 from django import forms
+from django.forms.widgets import flatatt
+from django.utils.encoding import force_unicode
+from django.utils.safestring import mark_safe
+
+class LinkWidget(forms.Widget):
+    def __init__(self, attrs=None, choices=()):
+        super(LinkWidget, self).__init__(attrs)
+
+        self.choices = list(choices)
+
+    def value_from_datadict(self, data, files, name):
+        value = super(LinkWidget, self).value_from_datadict(data, files, name)
+        self.data = data
+        return value
+
+    def render(self, name, value, attrs=None, choices=()):
+        if value is None:
+            value = ''
+        final_attrs = self.build_attrs(attrs)
+        output = [u'<ul%s>' % flatatt(final_attrs)]
+        options = self.render_options(choices, [value], name)
+        if options:
+            output.append(options)
+        output.append('</ul>')
+        return mark_safe(u'\n'.join(output))
+
+    def render_options(self, choices, selected_choices, name):
+        def render_option(option_value, option_label):
+            option_value = force_unicode(option_value)
+            data = self.data.copy()
+            data[name] = option_value
+            try:
+                url = data.urlencode()
+            except AttributeError:
+                url = '?%s' % urlencode(data)
+            return '<a href="%s">%s</a>' % (url, option_label)
+        selected_choices = set(force_unicode(v) for v in selected_choices)
+        output = []
+        for option_value, option_label in chain(self.choices, choices):
+            if isinstance(option_label, (list, tuple)):
+                for option in option_label:
+                    output.append(render_option(*option))
+            else:
+                output.append(render_option(option_value, option_label))
+        return u'\n'.join(output)
 
 class RangeWidget(forms.MultiWidget):
     def __init__(self, attrs=None):