1 files changed, 138 insertions, 0 deletions
diff --git a/actionpack/lib/action_dispatch/journey/nodes/node.rb b/actionpack/lib/action_dispatch/journey/nodes/node.rb
new file mode 100644
index 0000000000..2793c5668d
--- /dev/null
+++ b/actionpack/lib/action_dispatch/journey/nodes/node.rb
@@ -0,0 +1,138 @@
+require 'action_dispatch/journey/visitors'
+
+module ActionDispatch
+  module Journey # :nodoc:
+    module Nodes # :nodoc:
+      class Node # :nodoc:
+        include Enumerable
+
+        attr_accessor :left, :memo
+
+        def initialize(left)
+          @left = left
+          @memo = nil
+        end
+
+        def each(&block)
+          Visitors::Each::INSTANCE.accept(self, block)
+        end
+
+        def to_s
+          Visitors::String::INSTANCE.accept(self, '')
+        end
+
+        def to_dot
+          Visitors::Dot::INSTANCE.accept(self)
+        end
+
+        def to_sym
+          name.to_sym
+        end
+
+        def name
+          left.tr '*:'.freeze, ''.freeze
+        end
+
+        def type
+          raise NotImplementedError
+        end
+
+        def symbol?; false; end
+        def literal?; false; end
+        def terminal?; false; end
+        def star?; false; end
+        def cat?; false; end
+        def group?; false; end
+      end
+
+      class Terminal < Node # :nodoc:
+        alias :symbol :left
+        def terminal?; true; end
+      end
+
+      class Literal < Terminal # :nodoc:
+        def literal?; true; end
+        def type; :LITERAL; end
+      end
+
+      class Dummy < Literal # :nodoc:
+        def initialize(x = Object.new)
+          super
+        end
+
+        def literal?; false; end
+      end
+
+      %w{ Symbol Slash Dot }.each do |t|
+        class_eval <<-eoruby, __FILE__, __LINE__ + 1
+          class #{t} < Terminal;
+            def type; :#{t.upcase}; end
+          end
+        eoruby
+      end
+
+      class Symbol < Terminal # :nodoc:
+        attr_accessor :regexp
+        alias :symbol :regexp
+        attr_reader :name
+
+        DEFAULT_EXP = /[^\.\/\?]+/
+        def initialize(left)
+          super
+          @regexp = DEFAULT_EXP
+          @name = left.tr '*:'.freeze, ''.freeze
+        end
+
+        def default_regexp?
+          regexp == DEFAULT_EXP
+        end
+
+        def symbol?; true; end
+      end
+
+      class Unary < Node # :nodoc:
+        def children; [left] end
+      end
+
+      class Group < Unary # :nodoc:
+        def type; :GROUP; end
+        def group?; true; end
+      end
+
+      class Star < Unary # :nodoc:
+        def star?; true; end
+        def type; :STAR; end
+
+        def name
+          left.name.tr '*:', ''
+        end
+      end
+
+      class Binary < Node # :nodoc:
+        attr_accessor :right
+
+        def initialize(left, right)
+          super(left)
+          @right = right
+        end
+
+        def children; [left, right] end
+      end
+
+      class Cat < Binary # :nodoc:
+        def cat?; true; end
+        def type; :CAT; end
+      end
+
+      class Or < Node # :nodoc:
+        attr_reader :children
+
+        def initialize(children)
+          @children = children
+        end
+
+        def type; :OR; end
+      end
+    end
+  end
+end