allow date to be specified in the front matter and override the value…

… from the file name, fixes jekyll#62 and jekyll#38

lib/jekyll/post.rb

@@ -41,6 +41,13 @@ def initialize(site, source, dir, name)
       self.process(name)
       self.read_yaml(@base, name)
 
+      #If we've added a date and time to the yaml, use that instead of the filename date
+      #Means we'll sort correctly.
+      if self.data.has_key?('date')
+        # ensure Time via to_s and reparse
+        self.date = Time.parse(self.data["date"].to_s)
+      end
+
       if self.data.has_key?('published') && self.data['published'] == false
         self.published = false
       else

test/source/_posts/2010-01-09-date-override.textile

@@ -0,0 +1,5 @@
+---
+date: 2010-01-10
+---
+
+Post with a front matter date

test/source/_posts/2010-01-09-time-override.textile

@@ -0,0 +1,5 @@
+---
+date: 2010-01-10 13:07:09
+---
+
+Post with a front matter time

test/test_generated_site.rb

@@ -14,7 +14,7 @@ class TestGeneratedSite < Test::Unit::TestCase
     end
 
     should "ensure post count is as expected" do
-      assert_equal 18, @site.posts.size
+      assert_equal 20, @site.posts.size
     end
 
     should "insert site.posts into the index" do

test/test_post.rb

@@ -224,6 +224,16 @@ def do_render(post)
         assert_equal false, post.published
       end
 
+      should "recognize date in yaml" do
+        post = setup_post("2010-01-09-date-override.textile")
+        assert_equal "/2010/01/10/date-override.html", post.url
+      end
+
+      should "recognize time in yaml" do
+        post = setup_post("2010-01-09-time-override.textile")
+        assert_equal "/2010/01/10/time-override.html", post.url
+      end
+
       should "recognize category in yaml" do
         post = setup_post("2009-01-27-category.textile")
         assert post.categories.include?('foo')