1 files changed, 129 insertions, 0 deletions
diff --git a/lib/rdoc/markup/formatter.rb b/lib/rdoc/markup/formatter.rb
index 14cbae59f9..993e523f0c 100644
--- a/lib/rdoc/markup/formatter.rb
+++ b/lib/rdoc/markup/formatter.rb
@@ -1,14 +1,143 @@
 require 'rdoc/markup'
 
+##
+# Base class for RDoc markup formatters
+#
+# Formatters use a visitor pattern to convert content into output.
+
 class RDoc::Markup::Formatter
 
+  InlineTag = Struct.new(:bit, :on, :off)
+
+  ##
+  # Creates a new Formatter
+
   def initialize
     @markup = RDoc::Markup.new
+    @am = @markup.attribute_manager
+    @attr_tags = []
+
+    @in_tt = 0
+    @tt_bit = RDoc::Markup::Attribute.bitmap_for :TT
+  end
+
+  ##
+  # Add a new set of tags for an attribute. We allow separate start and end
+  # tags for flexibility
+
+  def add_tag(name, start, stop)
+    attr = RDoc::Markup::Attribute.bitmap_for name
+    @attr_tags << InlineTag.new(attr, start, stop)
+  end
+
+  ##
+  # Allows +tag+ to be decorated with additional information.
+
+  def annotate(tag)
+    tag
   end
 
+  ##
+  # Marks up +content+
+
   def convert(content)
     @markup.convert content, self
   end
 
+  ##
+  # Converts flow items +flow+
+
+  def convert_flow(flow)
+    res = []
+
+    flow.each do |item|
+      case item
+      when String then
+        res << convert_string(item)
+      when RDoc::Markup::AttrChanger then
+        off_tags res, item
+        on_tags res, item
+      when RDoc::Markup::Special then
+        res << convert_special(item)
+      else
+        raise "Unknown flow element: #{item.inspect}"
+      end
+    end
+
+    res.join
+  end
+
+  ##
+  # Converts added specials.  See RDoc::Markup#add_special
+
+  def convert_special(special)
+    handled = false
+
+    RDoc::Markup::Attribute.each_name_of special.type do |name|
+      method_name = "handle_special_#{name}"
+
+      if respond_to? method_name then
+        special.text = send method_name, special
+        handled = true
+      end
+    end
+
+    raise "Unhandled special: #{special}" unless handled
+
+    special.text
+  end
+
+  ##
+  # Converts a string to be fancier if desired
+
+  def convert_string string
+    string
+  end
+
+  ##
+  # Are we currently inside tt tags?
+
+  def in_tt?
+    @in_tt > 0
+  end
+
+  def on_tags res, item
+    attr_mask = item.turn_on
+    return if attr_mask.zero?
+
+    @attr_tags.each do |tag|
+      if attr_mask & tag.bit != 0 then
+        res << annotate(tag.on)
+        @in_tt += 1 if tt? tag
+      end
+    end
+  end
+
+  def off_tags res, item
+    attr_mask = item.turn_off
+    return if attr_mask.zero?
+
+    @attr_tags.reverse_each do |tag|
+      if attr_mask & tag.bit != 0 then
+        @in_tt -= 1 if tt? tag
+        res << annotate(tag.off)
+      end
+    end
+  end
+
+  ##
+  # Is +tag+ a tt tag?
+
+  def tt? tag
+    tag.bit == @tt_bit
+  end
+
 end
 
+class RDoc::Markup
+  autoload :ToAnsi,         'rdoc/markup/to_ansi'
+  autoload :ToBs,           'rdoc/markup/to_bs'
+  autoload :ToHtml,         'rdoc/markup/to_html'
+  autoload :ToHtmlCrossref, 'rdoc/markup/to_html_crossref'
+  autoload :ToRdoc,         'rdoc/markup/to_rdoc'
+end