Add smartify filter

lib/jekyll/converters/smartypants.rb

@@ -0,0 +1,34 @@
+class Kramdown::Parser::SmartyPants < Kramdown::Parser::Kramdown
+  def initialize(source, options)
+    super
+    @block_parsers = []
+    @span_parsers =  [:smart_quotes, :html_entity, :typographic_syms, :escaped_chars]
+  end
+end
+
+module Jekyll
+  module Converters
+    class SmartyPants < Converter
+      safe true
+      priority :low
+
+      def initialize(config)
+        Jekyll::External.require_with_graceful_fail "kramdown"
+        @config = config["kramdown"].dup || {}
+        @config[:input] = :SmartyPants
+      end
+
+      def matches(_)
+        false
+      end
+
+      def output_ext(_)
+        nil
+      end
+
+      def convert(content)
+        Kramdown::Document.new(content, @config).to_html.chomp
+      end
+    end
+  end
+end

lib/jekyll/filters.rb

@@ -15,6 +15,17 @@ module Jekyll
       converter.convert(input)
     end
 
+    # Convert a Markdown string into HTML output.
+    #
+    # input - The Markdown String to convert.
+    #
+    # Returns the HTML formatted String.
+    def smartify(input)
+      site = @context.registers[:site]
+      converter = site.find_converter_instance(Jekyll::Converters::SmartyPants)
+      converter.convert(input)
+    end
+
     # Convert a Sass string into CSS output.
     #
     # input - The Sass String to convert.

test/test_filters.rb

@@ -31,6 +31,11 @@ class TestFilters < JekyllUnitTest
       assert_equal "<p>something <strong>really</strong> simple</p>\n", @filter.markdownify("something **really** simple")
     end
 
+    should "smartify with simple string" do
+      assert_equal "SmartyPants is *not* Markdown", @filter.smartify("SmartyPants is *not* Markdown")
+      assert_equal "“This filter’s test…”", @filter.smartify(%q{"This filter's test..."})
+    end
+
     should "sassify with simple string" do
       assert_equal "p {\n  color: #123456; }\n", @filter.sassify("$blue:#123456\np\n  color: $blue")
     end