Support new private gist syntax.

lib/jekyll/tags/gist.rb

@@ -6,9 +6,10 @@
 
 module Jekyll
   class GistTag < Liquid::Tag
+
     def render(context)
-      if tag_contents = @markup.strip.match(/\A(\d+) ?(\S*)\Z/)
+      if tag_contents = determine_arguments(@markup.strip)
-        gist_id, filename = tag_contents[1].strip, tag_contents[2].strip
+        gist_id, filename = tag_contents[0], tag_contents[1]
         gist_script_tag(gist_id, filename)
       else
         "Error parsing gist id"
@@ -17,7 +18,16 @@ module Jekyll
 
     private
 
-    def gist_script_tag(gist_id, filename=nil)
+    def determine_arguments(input)
+      matched = if input.include?("/")
+        input.match(/\A([a-zA-Z0-9\/\-_]+) ?(\S*)\Z/)
+      else
+        input.match(/\A(\d+) ?(\S*)\Z/)
+      end
+      [matched[1].strip, matched[2].strip] if matched && matched.length >= 3
+    end
+
+    def gist_script_tag(gist_id, filename = nil)
       if filename.empty?
         "<script src=\"https://gist.github.com/#{gist_id}.js\"> </script>"
       else

test/test_tags.rb

@@ -253,6 +253,46 @@ CONTENT
       end
     end
 
+    context "for private gist" do
+      context "when valid" do
+        setup do
+          @gist = "mattr-/24081a1d93d2898ecf0f"
+          @filename = "myfile.ext"
+          content = <<CONTENT
+  ---
+  title: My Cool Gist
+  ---
+
+  {% gist #{@gist} #{@filename} %}
+CONTENT
+          create_post(content, {'permalink' => 'pretty', 'source' => source_dir, 'destination' => dest_dir, 'read_posts' => true})
+        end
+
+        should "write script tag with specific file in gist" do
+          assert_match "<script src='https://gist.github.com/#{@gist}.js?file=#{@filename}'>\s</script>", @result
+        end
+      end
+
+      context "when invalid" do
+        setup do
+          @gist = "mattr-24081a1d93d2898ecf0f"
+          @filename = "myfile.ext"
+          content = <<CONTENT
+  ---
+  title: My Cool Gist
+  ---
+
+  {% gist #{@gist} #{@filename} %}
+CONTENT
+          create_post(content, {'permalink' => 'pretty', 'source' => source_dir, 'destination' => dest_dir, 'read_posts' => true})
+        end
+
+        should "write script tag with specific file in gist" do
+          assert_match "Error parsing gist id", @result
+        end
+      end
+    end
+
     context "with specific file" do
       setup do
         @gist = 358471