1 files changed, 86 insertions, 0 deletions
diff --git a/lib/rdoc/parsers/parserfactory.rb b/lib/rdoc/parsers/parserfactory.rb
new file mode 100644
index 0000000000..dc7d629903
--- /dev/null
+++ b/lib/rdoc/parsers/parserfactory.rb
@@ -0,0 +1,86 @@
+require "rdoc/parsers/parse_simple"
+
+module RDoc
+
+  # A parser is simple a class that implements
+  #
+  #   #initialize(file_name, body, options)
+  #
+  # and
+  #
+  #   #scan
+  #
+  # The initialize method takes a file name to be used, the body of the
+  # file, and an RDoc::Options object. The scan method is then called
+  # to return an appropriately parsed TopLevel code object.
+
+  # The ParseFactory is used to redirect to the correct parser given a filename
+  # extension. This magic works because individual parsers have to register 
+  # themselves with us as they are loaded in. The do this using the following
+  # incantation
+  #
+  #
+  #    require "rdoc/parsers/parsefactory"
+  #    
+  #    module RDoc
+  #    
+  #      class XyzParser
+  #        extend ParseFactory                  <<<<
+  #        parse_files_matching /\.xyz$/        <<<<
+  #    
+  #        def initialize(file_name, body, options)
+  #          ...
+  #        end
+  #    
+  #        def scan
+  #          ...
+  #        end
+  #      end
+  #    end
+
+
+
+  module ParserFactory
+
+    @@parsers = []
+
+    Parsers = Struct.new(:regexp, :parser)
+
+    # Record the fact that a particular class parses files that
+    # match a given extension
+
+    def parse_files_matching(regexp)
+      @@parsers.unshift Parsers.new(regexp, self)
+    end
+
+    # Return a parser that can handle a particular extension
+
+    def ParserFactory.can_parse(file_name)
+      @@parsers.find {|p| p.regexp.match(file_name) }
+    end
+
+    # Alias an extension to another extension. After this call,
+    # files ending "new_ext" will be parsed using the same parser
+    # as "old_ext"
+
+    def ParserFactory.alias_extension(old_ext, new_ext)
+      parser = ParserFactory.can_parse("xxx.#{old_ext}")
+      return false unless parser
+      @@parsers.unshift Parsers.new(Regexp.new("\\.#{new_ext}$"), parser.parser)
+      true
+    end
+
+    # Find the correct parser for a particular file name. Return a 
+    # SimpleParser for ones that we don't know
+
+    def ParserFactory.parser_for(top_level, file_name, body, options)
+      parser_description = can_parse(file_name)
+      if parser_description
+        parser = parser_description.parser 
+      else
+        parser = SimpleParser
+      end
+      parser.new(top_level, file_name, body, options)
+    end
+  end
+end