From 2c434ebac1c64ac2da85cdeeadeaf2c3bd5307cc Mon Sep 17 00:00:00 2001
From: "W. Trevor King" <wking@tremily.us>
Date: Thu, 3 Jan 2013 13:54:56 -0500
Subject: [PATCH] contents: Add rich comparisons to URLWrapper for easy sorting

There have been earlier attempts to sort categories and authors
[1,2,3], but they either sorted based on the object id [3], or only
sorted the main author and categories list.

This patch uses rich comparisons (keyed off URLWrapper.name, but
easily adjustable in subclasses) to make the objects sortable without
specifying a key for each sort.  For example, now

  {% for tag, articles in tags|sort %}

works as expected in a Jinja template.

The functools.total_ordering decorator fills in the missing rich
comparisons [4,5].

[1]: 877d454c8fa979343d4881a00977d9ac8786f178
[2]: 7f36e0ed20745c73886d96d4af303b0d858b8a53
[3]: d0ec18f4dbd623c55bdf4928ee7c363f699ef696
[4]: http://docs.python.org/2/library/functools.html#functools.total_ordering
[5]: http://docs.python.org/3/library/functools.html#functools.total_ordering
---
 pelican/contents.py   | 16 +++++++++++++++-
 pelican/generators.py |  3 +--
 2 files changed, 16 insertions(+), 3 deletions(-)

diff --git a/pelican/contents.py b/pelican/contents.py
index 4655d4cc..bd257ad8 100644
--- a/pelican/contents.py
+++ b/pelican/contents.py
@@ -243,7 +243,9 @@ class Article(Page):
 class Quote(Page):
     base_properties = ('author', 'date')
 
+
 @python_2_unicode_compatible
+@functools.total_ordering
 class URLWrapper(object):
     def __init__(self, name, settings):
         self.name = name
@@ -256,8 +258,20 @@ class URLWrapper(object):
     def __hash__(self):
         return hash(self.name)
 
+    def _key(self):
+        return self.name
+
+    def _normalize_key(self, key):
+        return six.text_type(key)
+
     def __eq__(self, other):
-        return self.name == other
+        return self._key() == self._normalize_key(other)
+
+    def __ne__(self, other):
+        return self._key() != self._normalize_key(other)
+
+    def __lt__(self, other):
+        return self._key() < self._normalize_key(other)
 
     def __str__(self):
         return self.name
diff --git a/pelican/generators.py b/pelican/generators.py
index ce102a31..49b6bc1d 100644
--- a/pelican/generators.py
+++ b/pelican/generators.py
@@ -416,11 +416,10 @@ class ArticlesGenerator(Generator):
         # order the categories per name
         self.categories = list(self.categories.items())
         self.categories.sort(
-                key=lambda item: item[0].name,
                 reverse=self.settings['REVERSE_CATEGORY_ORDER'])
 
         self.authors = list(self.authors.items())
-        self.authors.sort(key=lambda item: item[0].name)
+        self.authors.sort()
 
         self._update_context(('articles', 'dates', 'tags', 'categories',
                               'tag_cloud', 'authors', 'related_posts'))