While testing md2man master with JRuby 1.6.8, I got this error:
undefined method `each_key' for :Array
However, md2man works fine under MRI 1.9.3.
I just observed that Redcarpet 2.2.1 doesn't build under Ruby 1.8.7, in addition to JRuby as #9 reports.
I've become weary of Ruby 1.8's syntax and stdlib limitations, so I'm tempted to stop supporting it. 😫
1.8.7 is dying, so it might be time to add required_ruby_version = '>= 1.9.1' to the gemspec.
required_ruby_version = '>= 1.9.1'
Ah, so that's how it's done! Thanks for the tip.
GH-8: Redcarpet requires Ruby 1.9 and so must we
Fixed in 66a0dab.
Thanks to Postmodern for raising this issue.