Formatting of dates and times in a DRY manner

[alzeih]

May make it easier to make changes to the format, i.e: to match the default format suggested

"YYYY-MM-DD HH:MM:SS +/-TTTT" as from https://jekyllrb.com/docs/frontmatter/

or to make these configurable values.

[alzeih]

n.b: The format is also assumed by jekyll unpublish

      def name
        File.basename(path).sub %r!\d{4}-\d{2}-\d{2}-!, ""
      end

So if any changes to Jekyll::Compose::DEFAULT_DATESTAMP_FORMAT are made, it will also need to be reflected there.

This could probably be done with something like this (if the format is configurable):

diff --git a/lib/jekyll/commands/unpublish.rb b/lib/jekyll/commands/unpublish.rb
index 528f9bf..03f9b17 100644
--- a/lib/jekyll/commands/unpublish.rb
+++ b/lib/jekyll/commands/unpublish.rb
@@ -35,7 +35,12 @@ module Jekyll
       end
 
       def name
-        File.basename(path).sub %r!\d{4}-\d{2}-\d{2}-!, ""
+       begin
+          date = Time.parse(File.basename(path)).strftime(Jekyll::Compose::DEFAULT_DATESTAMP_FORMAT)
+          File.basename(path).sub "#{date}-", ""
+       rescue
+         File.basename(path).sub %r!\d{4}-\d{2}-\d{2}-!, ""
+       end
       end
     end

Although a post's title in a filename that appears valid to Time.parse could be altered unexpectedly.

[DirtyF]

@jekyllbot: merge +dev