1 files changed, 191 insertions, 0 deletions
diff --git a/jni/ruby/lib/rdoc/markup/to_markdown.rb b/jni/ruby/lib/rdoc/markup/to_markdown.rb
new file mode 100644
index 0000000..d4b15bf
--- /dev/null
+++ b/jni/ruby/lib/rdoc/markup/to_markdown.rb
@@ -0,0 +1,191 @@
+# :markup: markdown
+
+##
+# Outputs parsed markup as Markdown
+
+class RDoc::Markup::ToMarkdown < RDoc::Markup::ToRdoc
+
+  ##
+  # Creates a new formatter that will output Markdown format text
+
+  def initialize markup = nil
+    super
+
+    @headings[1] = ['# ',      '']
+    @headings[2] = ['## ',     '']
+    @headings[3] = ['### ',    '']
+    @headings[4] = ['#### ',   '']
+    @headings[5] = ['##### ',  '']
+    @headings[6] = ['###### ', '']
+
+    add_special_RDOCLINK
+    add_special_TIDYLINK
+
+    @hard_break = "  \n"
+  end
+
+  ##
+  # Maps attributes to HTML sequences
+
+  def init_tags
+    add_tag :BOLD, '**', '**'
+    add_tag :EM,   '*',  '*'
+    add_tag :TT,   '`',  '`'
+  end
+
+  ##
+  # Adds a newline to the output
+
+  def handle_special_HARD_BREAK special
+    "  \n"
+  end
+
+  ##
+  # Finishes consumption of `list`
+
+  def accept_list_end list
+    @res << "\n"
+
+    super
+  end
+
+  ##
+  # Finishes consumption of `list_item`
+
+  def accept_list_item_end list_item
+    width = case @list_type.last
+            when :BULLET then
+              4
+            when :NOTE, :LABEL then
+              use_prefix
+
+              4
+            else
+              @list_index[-1] = @list_index.last.succ
+              4
+            end
+
+    @indent -= width
+  end
+
+  ##
+  # Prepares the visitor for consuming `list_item`
+
+  def accept_list_item_start list_item
+    type = @list_type.last
+
+    case type
+    when :NOTE, :LABEL then
+      bullets = Array(list_item.label).map do |label|
+        attributes(label).strip
+      end.join "\n"
+
+      bullets << "\n:"
+
+      @prefix = ' ' * @indent
+      @indent += 4
+      @prefix << bullets + (' ' * (@indent - 1))
+    else
+      bullet = type == :BULLET ? '*' : @list_index.last.to_s + '.'
+      @prefix = (' ' * @indent) + bullet.ljust(4)
+
+      @indent += 4
+    end
+  end
+
+  ##
+  # Prepares the visitor for consuming `list`
+
+  def accept_list_start list
+    case list.type
+    when :BULLET, :LABEL, :NOTE then
+      @list_index << nil
+    when :LALPHA, :NUMBER, :UALPHA then
+      @list_index << 1
+    else
+      raise RDoc::Error, "invalid list type #{list.type}"
+    end
+
+    @list_width << 4
+    @list_type << list.type
+  end
+
+  ##
+  # Adds `rule` to the output
+
+  def accept_rule rule
+    use_prefix or @res << ' ' * @indent
+    @res << '-' * 3
+    @res << "\n"
+  end
+
+  ##
+  # Outputs `verbatim` indented 4 columns
+
+  def accept_verbatim verbatim
+    indent = ' ' * (@indent + 4)
+
+    verbatim.parts.each do |part|
+      @res << indent unless part == "\n"
+      @res << part
+    end
+
+    @res << "\n" unless @res =~ /\n\z/
+  end
+
+  ##
+  # Creates a Markdown-style URL from +url+ with +text+.
+
+  def gen_url url, text
+    scheme, url, = parse_url url
+
+    "[#{text.sub(%r{^#{scheme}:/*}i, '')}](#{url})"
+  end
+
+  ##
+  # Handles <tt>rdoc-</tt> type links for footnotes.
+
+  def handle_rdoc_link url
+    case url
+    when /^rdoc-ref:/ then
+      $'
+    when /^rdoc-label:footmark-(\d+)/ then
+      "[^#{$1}]:"
+    when /^rdoc-label:foottext-(\d+)/ then
+      "[^#{$1}]"
+    when /^rdoc-label:label-/ then
+      gen_url url, $'
+    when /^rdoc-image:/ then
+      "![](#{$'})"
+    when /^rdoc-[a-z]+:/ then
+      $'
+    end
+  end
+
+  ##
+  # Converts the RDoc markup tidylink into a Markdown.style link.
+
+  def handle_special_TIDYLINK special
+    text = special.text
+
+    return text unless text =~ /\{(.*?)\}\[(.*?)\]/ or text =~ /(\S+)\[(.*?)\]/
+
+    label = $1
+    url   = $2
+
+    if url =~ /^rdoc-label:foot/ then
+      handle_rdoc_link url
+    else
+      gen_url url, label
+    end
+  end
+
+  ##
+  # Converts the rdoc-...: links into a Markdown.style links.
+
+  def handle_special_RDOCLINK special
+    handle_rdoc_link special.text
+  end
+
+end
+