avoid is_a? checks

add another predicate method so we can avoid is_a checks

actionpack/lib/action_dispatch/journey/nodes/node.rb

@@ -40,6 +40,7 @@ module ActionDispatch
         def symbol?; false; end
         def literal?; false; end
         def terminal?; false; end
+        def star?; false; end
       end
 
       class Terminal < Node # :nodoc:
@@ -94,6 +95,7 @@ module ActionDispatch
       end
 
       class Star < Unary # :nodoc:
+        def star?; true; end
         def type; :STAR; end
 
         def name

actionpack/lib/action_dispatch/journey/path/pattern.rb

@@ -32,12 +32,12 @@ module ActionDispatch
         end
 
         def ast
-          @spec.grep(Nodes::Symbol).each do |node|
+          @spec.find_all(&:symbol?).each do |node|
             re = @requirements[node.to_sym]
             node.regexp = re if re
           end
 
-          @spec.grep(Nodes::Star).each do |node|
+          @spec.find_all(&:star?).each do |node|
             node = node.left
             node.regexp = @requirements[node.to_sym] || /(.+)/
           end