add support for sorting using numeric values

features/sorting.feature

@@ -200,17 +200,17 @@ Feature: Sorting BibTeX Bibliographies
     And I have a file "_bibliography/references.bib":
       """
       @book{ruby1,
-        title     = {December},
+        title     = {December 08},
         year      = {2008},
         month     = dec
       }
       @book{ruby2,
-        title     = {March},
+        title     = {March 08},
         year      = {2008},
         month     = mar
       }
       @book{ruby3,
-        title     = {August},
+        title     = {August 07},
         year      = {2007},
         month     = aug
       }
@@ -224,5 +224,5 @@ Feature: Sorting BibTeX Bibliographies
     When I run jekyll
     Then the _site directory should exist
     And the "_site/scholar.html" file should exist
-    Then "August" should come before "March" in "_site/scholar.html"
-#    And "March" should come before "December" in "_site/scholar.html"
+    Then "August 07" should come before "March 08" in "_site/scholar.html"
+    And "March 08" should come before "December 08" in "_site/scholar.html"

jekyll-scholar.gemspec

@@ -28,7 +28,7 @@ Gem::Specification.new do |s|
   s.add_runtime_dependency('jekyll', '~> 2.0')
   s.add_runtime_dependency('citeproc-ruby', '~> 1.0')
   s.add_runtime_dependency('csl-styles', '~> 1.0')
-  s.add_runtime_dependency('bibtex-ruby', '>= 4.0.6')
+  s.add_runtime_dependency('bibtex-ruby', '>= 4.0.8')
 
   s.files        = `git ls-files`.split("\n")
   s.test_files   = `git ls-files -- {test,spec,features}/*`.split("\n")

lib/jekyll/scholar/defaults.rb

@@ -13,7 +13,7 @@ module Jekyll
       'bibliography'          => 'references.bib',
       'repository'            => nil,
 
-      'bibtex_options'        => { :strip => false },
+      'bibtex_options'        => { :strip => false, :parse_months => true },
       'bibtex_filters'        => [ :latex ],
 
       'replace_strings'       => true,

lib/jekyll/scholar/utilities.rb

@@ -141,16 +141,18 @@ module Jekyll
       def sort(unsorted)
         return unsorted if skip_sort?
 
-        puts unsorted.first.values_at(*sort_keys)
-        sorted = unsorted.sort_by { |e| e.values_at(*sort_keys) }
+        sorted = unsorted.sort_by { |e| e.values_at(*sort_keys).map(&:v) }
         sorted.reverse! if config['order'] =~ /^(desc|reverse)/i
         sorted
       end
 
       def sort_keys
-        @sort_kyes ||= Array(config['sort_by']).map { |key|
-          key.to_s.split(/\s*,\s*/)
-        }.flatten
+        return @sort_keys unless @sort_keys.nil?
+
+        @sort_keys = Array(config['sort_by'])
+          .map { |key| key.to_s.split(/\s*,\s*/) }
+          .flatten
+          .map { |key| key == 'month' ? 'month_numeric' : key }
       end
 
       def suppress_author?