add support for symbol type

lib/kansen/mapper/note_parser.rb

@@ -2,17 +2,16 @@ module Kansen
   module Mapper
     module NoteParser
 
-      PARSERS =
-        { 'string'   => 'Null',
-          'integer'  => 'Integer',
-          'float'    => 'Float',
-          'constant' => 'Constant' }
+      PARSERS = {
+        'string'   => 'Null',
+        'integer'  => 'Integer',
+        'float'    => 'Float',
+        'constant' => 'Constant',
+        'symbol'   => 'Symbol'
+      }.freeze
 
       def self.parse(type, note)
-        Kernel.
-          const_get('Kansen').
-          const_get('Parser').
-          const_get(PARSERS[type]).parse(note)
+        Kernel.const_get('Kansen').const_get('Parser').const_get(PARSERS[type]).parse(note)
       rescue
         raise Kansen::MissingParser
       end

lib/kansen/mapper/note_type.rb

@@ -2,9 +2,9 @@ module Kansen
   module Mapper
     module NoteType
 
-      TYPES = %w{
-        string integer float constant
-      }
+      TYPES = %w[
+        string integer float constant symbol
+      ].freeze
 
       def self.perform(type)
         raise Kansen::WrongNoteType unless TYPES.include? type

lib/kansen/parser.rb

@@ -2,3 +2,4 @@
 require 'kansen/parser/integer'
 require 'kansen/parser/constant'
 require 'kansen/parser/null'
+require 'kansen/parser/symbol'

lib/kansen/parser/symbol.rb

@@ -0,0 +1,7 @@
+module Kansen::Parser
+  class Symbol
+    def self.parse(note)
+      note.to_sym
+    end
+  end
+end