Fresh start

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diff --git a/jni/ruby/lib/racc/parser.rb b/jni/ruby/lib/racc/parser.rb
new file mode 100644
index 0000000..f811ab6
--- /dev/null
+++ b/jni/ruby/lib/racc/parser.rb
@@ -0,0 +1,622 @@
+#--
+# $originalId: parser.rb,v 1.8 2006/07/06 11:42:07 aamine Exp $
+#
+# Copyright (c) 1999-2006 Minero Aoki
+#
+# This program is free software.
+# You can distribute/modify this program under the same terms of ruby.
+#
+# As a special exception, when this code is copied by Racc
+# into a Racc output file, you may use that output file
+# without restriction.
+#++
+
+module Racc
+  class ParseError < StandardError; end
+end
+unless defined?(::ParseError)
+  ParseError = Racc::ParseError
+end
+
+# Racc is a LALR(1) parser generator.
+# It is written in Ruby itself, and generates Ruby programs.
+#
+# == Command-line Reference
+#
+#     racc [-o<var>filename</var>] [--output-file=<var>filename</var>]
+#          [-e<var>rubypath</var>] [--embedded=<var>rubypath</var>]
+#          [-v] [--verbose]
+#          [-O<var>filename</var>] [--log-file=<var>filename</var>]
+#          [-g] [--debug]
+#          [-E] [--embedded]
+#          [-l] [--no-line-convert]
+#          [-c] [--line-convert-all]
+#          [-a] [--no-omit-actions]
+#          [-C] [--check-only]
+#          [-S] [--output-status]
+#          [--version] [--copyright] [--help] <var>grammarfile</var>
+#
+# [+filename+]
+#   Racc grammar file. Any extension is permitted.
+# [-o+outfile+, --output-file=+outfile+]
+#   A filename for output. default is <+filename+>.tab.rb
+# [-O+filename+, --log-file=+filename+]
+#   Place logging output in file +filename+.
+#   Default log file name is <+filename+>.output.
+# [-e+rubypath+, --executable=+rubypath+]
+#   output executable file(mode 755). where +path+ is the Ruby interpreter.
+# [-v, --verbose]
+#   verbose mode. create +filename+.output file, like yacc's y.output file.
+# [-g, --debug]
+#   add debug code to parser class. To display debugging information,
+#   use this '-g' option and set @yydebug true in parser class.
+# [-E, --embedded]
+#   Output parser which doesn't need runtime files (racc/parser.rb).
+# [-C, --check-only]
+#   Check syntax of racc grammar file and quit.
+# [-S, --output-status]
+#   Print messages time to time while compiling.
+# [-l, --no-line-convert]
+#   turns off line number converting.
+# [-c, --line-convert-all]
+#   Convert line number of actions, inner, header and footer.
+# [-a, --no-omit-actions]
+#   Call all actions, even if an action is empty.
+# [--version]
+#   print Racc version and quit.
+# [--copyright]
+#   Print copyright and quit.
+# [--help]
+#   Print usage and quit.
+#
+# == Generating Parser Using Racc
+#
+# To compile Racc grammar file, simply type:
+#
+#   $ racc parse.y
+#
+# This creates Ruby script file "parse.tab.y". The -o option can change the output filename.
+#
+# == Writing A Racc Grammar File
+#
+# If you want your own parser, you have to write a grammar file.
+# A grammar file contains the name of your parser class, grammar for the parser,
+# user code, and anything else.
+# When writing a grammar file, yacc's knowledge is helpful.
+# If you have not used yacc before, Racc is not too difficult.
+#
+# Here's an example Racc grammar file.
+#
+#   class Calcparser
+#   rule
+#     target: exp { print val[0] }
+#
+#     exp: exp '+' exp
+#        | exp '*' exp
+#        | '(' exp ')'
+#        | NUMBER
+#   end
+#
+# Racc grammar files resemble yacc files.
+# But (of course), this is Ruby code.
+# yacc's $$ is the 'result', $0, $1... is
+# an array called 'val', and $-1, $-2... is an array called '_values'.
+#
+# See the {Grammar File Reference}[rdoc-ref:lib/racc/rdoc/grammar.en.rdoc] for
+# more information on grammar files.
+#
+# == Parser
+#
+# Then you must prepare the parse entry method. There are two types of
+# parse methods in Racc, Racc::Parser#do_parse and Racc::Parser#yyparse
+#
+# Racc::Parser#do_parse is simple.
+#
+# It's yyparse() of yacc, and Racc::Parser#next_token is yylex().
+# This method must returns an array like [TOKENSYMBOL, ITS_VALUE].
+# EOF is [false, false].
+# (TOKENSYMBOL is a Ruby symbol (taken from String#intern) by default.
+# If you want to change this, see the grammar reference.
+#
+# Racc::Parser#yyparse is little complicated, but useful.
+# It does not use Racc::Parser#next_token, instead it gets tokens from any iterator.
+#
+# For example, <code>yyparse(obj, :scan)</code> causes
+# calling +obj#scan+, and you can return tokens by yielding them from +obj#scan+.
+#
+# == Debugging
+#
+# When debugging, "-v" or/and the "-g" option is helpful.
+#
+# "-v" creates verbose log file (.output).
+# "-g" creates a "Verbose Parser".
+# Verbose Parser prints the internal status when parsing.
+# But it's _not_ automatic.
+# You must use -g option and set +@yydebug+ to +true+ in order to get output.
+# -g option only creates the verbose parser.
+#
+# === Racc reported syntax error.
+#
+# Isn't there too many "end"?
+# grammar of racc file is changed in v0.10.
+#
+# Racc does not use '%' mark, while yacc uses huge number of '%' marks..
+#
+# === Racc reported "XXXX conflicts".
+#
+# Try "racc -v xxxx.y".
+# It causes producing racc's internal log file, xxxx.output.
+#
+# === Generated parsers does not work correctly
+#
+# Try "racc -g xxxx.y".
+# This command let racc generate "debugging parser".
+# Then set @yydebug=true in your parser.
+# It produces a working log of your parser.
+#
+# == Re-distributing Racc runtime
+#
+# A parser, which is created by Racc, requires the Racc runtime module;
+# racc/parser.rb.
+#
+# Ruby 1.8.x comes with Racc runtime module,
+# you need NOT distribute Racc runtime files.
+#
+# If you want to include the Racc runtime module with your parser.
+# This can be done by using '-E' option:
+#
+#   $ racc -E -omyparser.rb myparser.y
+#
+# This command creates myparser.rb which `includes' Racc runtime.
+# Only you must do is to distribute your parser file (myparser.rb).
+#
+# Note: parser.rb is LGPL, but your parser is not.
+# Your own parser is completely yours.
+module Racc
+
+  unless defined?(Racc_No_Extensions)
+    Racc_No_Extensions = false # :nodoc:
+  end
+
+  class Parser
+
+    Racc_Runtime_Version = '1.4.6'
+    Racc_Runtime_Revision = %w$originalRevision: 1.8 $[1]
+
+    Racc_Runtime_Core_Version_R = '1.4.6'
+    Racc_Runtime_Core_Revision_R = %w$originalRevision: 1.8 $[1]
+    begin
+      require 'racc/cparse'
+    # Racc_Runtime_Core_Version_C  = (defined in extension)
+      Racc_Runtime_Core_Revision_C = Racc_Runtime_Core_Id_C.split[2]
+      unless new.respond_to?(:_racc_do_parse_c, true)
+        raise LoadError, 'old cparse.so'
+      end
+      if Racc_No_Extensions
+        raise LoadError, 'selecting ruby version of racc runtime core'
+      end
+
+      Racc_Main_Parsing_Routine    = :_racc_do_parse_c # :nodoc:
+      Racc_YY_Parse_Method         = :_racc_yyparse_c # :nodoc:
+      Racc_Runtime_Core_Version    = Racc_Runtime_Core_Version_C # :nodoc:
+      Racc_Runtime_Core_Revision   = Racc_Runtime_Core_Revision_C # :nodoc:
+      Racc_Runtime_Type            = 'c' # :nodoc:
+    rescue LoadError
+      Racc_Main_Parsing_Routine    = :_racc_do_parse_rb
+      Racc_YY_Parse_Method         = :_racc_yyparse_rb
+      Racc_Runtime_Core_Version    = Racc_Runtime_Core_Version_R
+      Racc_Runtime_Core_Revision   = Racc_Runtime_Core_Revision_R
+      Racc_Runtime_Type            = 'ruby'
+    end
+
+    def Parser.racc_runtime_type # :nodoc:
+      Racc_Runtime_Type
+    end
+
+    def _racc_setup
+      @yydebug = false unless self.class::Racc_debug_parser
+      @yydebug = false unless defined?(@yydebug)
+      if @yydebug
+        @racc_debug_out = $stderr unless defined?(@racc_debug_out)
+        @racc_debug_out ||= $stderr
+      end
+      arg = self.class::Racc_arg
+      arg[13] = true if arg.size < 14
+      arg
+    end
+
+    def _racc_init_sysvars
+      @racc_state  = [0]
+      @racc_tstack = []
+      @racc_vstack = []
+
+      @racc_t = nil
+      @racc_val = nil
+
+      @racc_read_next = true
+
+      @racc_user_yyerror = false
+      @racc_error_status = 0
+    end
+
+    # The entry point of the parser. This method is used with #next_token.
+    # If Racc wants to get token (and its value), calls next_token.
+    #
+    # Example:
+    #     def parse
+    #       @q = [[1,1],
+    #             [2,2],
+    #             [3,3],
+    #             [false, '$']]
+    #       do_parse
+    #     end
+    #
+    #     def next_token
+    #       @q.shift
+    #     end
+    def do_parse
+      __send__(Racc_Main_Parsing_Routine, _racc_setup(), false)
+    end
+
+    # The method to fetch next token.
+    # If you use #do_parse method, you must implement #next_token.
+    #
+    # The format of return value is [TOKEN_SYMBOL, VALUE].
+    # +token-symbol+ is represented by Ruby's symbol by default, e.g. :IDENT
+    # for 'IDENT'.  ";" (String) for ';'.
+    #
+    # The final symbol (End of file) must be false.
+    def next_token
+      raise NotImplementedError, "#{self.class}\#next_token is not defined"
+    end
+
+    def _racc_do_parse_rb(arg, in_debug)
+      action_table, action_check, action_default, action_pointer,
+      _,            _,            _,              _,
+      _,            _,            token_table,    _,
+      _,            _,            * = arg
+
+      _racc_init_sysvars
+      tok = act = i = nil
+
+      catch(:racc_end_parse) {
+        while true
+          if i = action_pointer[@racc_state[-1]]
+            if @racc_read_next
+              if @racc_t != 0   # not EOF
+                tok, @racc_val = next_token()
+                unless tok      # EOF
+                  @racc_t = 0
+                else
+                  @racc_t = (token_table[tok] or 1)   # error token
+                end
+                racc_read_token(@racc_t, tok, @racc_val) if @yydebug
+                @racc_read_next = false
+              end
+            end
+            i += @racc_t
+            unless i >= 0 and
+                   act = action_table[i] and
+                   action_check[i] == @racc_state[-1]
+              act = action_default[@racc_state[-1]]
+            end
+          else
+            act = action_default[@racc_state[-1]]
+          end
+          while act = _racc_evalact(act, arg)
+            ;
+          end
+        end
+      }
+    end
+
+    # Another entry point for the parser.
+    # If you use this method, you must implement RECEIVER#METHOD_ID method.
+    #
+    # RECEIVER#METHOD_ID is a method to get next token.
+    # It must 'yield' the token, which format is [TOKEN-SYMBOL, VALUE].
+    def yyparse(recv, mid)
+      __send__(Racc_YY_Parse_Method, recv, mid, _racc_setup(), true)
+    end
+
+    def _racc_yyparse_rb(recv, mid, arg, c_debug)
+      action_table, action_check, action_default, action_pointer,
+      _,             _,            _,              _,
+      _,            _,            token_table,    _,
+      _,            _,            * = arg
+
+      _racc_init_sysvars
+      act = nil
+      i = nil
+
+      catch(:racc_end_parse) {
+        until i = action_pointer[@racc_state[-1]]
+          while act = _racc_evalact(action_default[@racc_state[-1]], arg)
+            ;
+          end
+        end
+        recv.__send__(mid) do |tok, val|
+          unless tok
+            @racc_t = 0
+          else
+            @racc_t = (token_table[tok] or 1)   # error token
+          end
+          @racc_val = val
+          @racc_read_next = false
+
+          i += @racc_t
+          unless i >= 0 and
+                 act = action_table[i] and
+                 action_check[i] == @racc_state[-1]
+            act = action_default[@racc_state[-1]]
+          end
+          while act = _racc_evalact(act, arg)
+            ;
+          end
+
+          while not(i = action_pointer[@racc_state[-1]]) or
+                not @racc_read_next or
+                @racc_t == 0   # $
+            unless i and i += @racc_t and
+                   i >= 0 and
+                   act = action_table[i] and
+                   action_check[i] == @racc_state[-1]
+              act = action_default[@racc_state[-1]]
+            end
+            while act = _racc_evalact(act, arg)
+              ;
+            end
+          end
+        end
+      }
+    end
+
+    ###
+    ### common
+    ###
+
+    def _racc_evalact(act, arg)
+      action_table, action_check, _, action_pointer,
+      _,   _, _, _,
+      _,   _, _, shift_n,  reduce_n,
+      _,   _, * = arg
+
+      if act > 0 and act < shift_n
+        #
+        # shift
+        #
+        if @racc_error_status > 0
+          @racc_error_status -= 1 unless @racc_t == 1   # error token
+        end
+        @racc_vstack.push @racc_val
+        @racc_state.push act
+        @racc_read_next = true
+        if @yydebug
+          @racc_tstack.push @racc_t
+          racc_shift @racc_t, @racc_tstack, @racc_vstack
+        end
+
+      elsif act < 0 and act > -reduce_n
+        #
+        # reduce
+        #
+        code = catch(:racc_jump) {
+          @racc_state.push _racc_do_reduce(arg, act)
+          false
+        }
+        if code
+          case code
+          when 1 # yyerror
+            @racc_user_yyerror = true   # user_yyerror
+            return -reduce_n
+          when 2 # yyaccept
+            return shift_n
+          else
+            raise '[Racc Bug] unknown jump code'
+          end
+        end
+
+      elsif act == shift_n
+        #
+        # accept
+        #
+        racc_accept if @yydebug
+        throw :racc_end_parse, @racc_vstack[0]
+
+      elsif act == -reduce_n
+        #
+        # error
+        #
+        case @racc_error_status
+        when 0
+          unless arg[21]    # user_yyerror
+            on_error @racc_t, @racc_val, @racc_vstack
+          end
+        when 3
+          if @racc_t == 0   # is $
+            throw :racc_end_parse, nil
+          end
+          @racc_read_next = true
+        end
+        @racc_user_yyerror = false
+        @racc_error_status = 3
+        while true
+          if i = action_pointer[@racc_state[-1]]
+            i += 1   # error token
+            if  i >= 0 and
+                (act = action_table[i]) and
+                action_check[i] == @racc_state[-1]
+              break
+            end
+          end
+          throw :racc_end_parse, nil if @racc_state.size <= 1
+          @racc_state.pop
+          @racc_vstack.pop
+          if @yydebug
+            @racc_tstack.pop
+            racc_e_pop @racc_state, @racc_tstack, @racc_vstack
+          end
+        end
+        return act
+
+      else
+        raise "[Racc Bug] unknown action #{act.inspect}"
+      end
+
+      racc_next_state(@racc_state[-1], @racc_state) if @yydebug
+
+      nil
+    end
+
+    def _racc_do_reduce(arg, act)
+      _, _, _, _,
+      goto_table,   goto_check,   goto_default,   goto_pointer,
+      nt_base,      reduce_table, _,    _,
+      _,     use_result,   * = arg
+      state = @racc_state
+      vstack = @racc_vstack
+      tstack = @racc_tstack
+
+      i = act * -3
+      len       = reduce_table[i]
+      reduce_to = reduce_table[i+1]
+      method_id = reduce_table[i+2]
+      void_array = []
+
+      tmp_t = tstack[-len, len] if @yydebug
+      tmp_v = vstack[-len, len]
+      tstack[-len, len] = void_array if @yydebug
+      vstack[-len, len] = void_array
+      state[-len, len]  = void_array
+
+      # tstack must be updated AFTER method call
+      if use_result
+        vstack.push __send__(method_id, tmp_v, vstack, tmp_v[0])
+      else
+        vstack.push __send__(method_id, tmp_v, vstack)
+      end
+      tstack.push reduce_to
+
+      racc_reduce(tmp_t, reduce_to, tstack, vstack) if @yydebug
+
+      k1 = reduce_to - nt_base
+      if i = goto_pointer[k1]
+        i += state[-1]
+        if i >= 0 and (curstate = goto_table[i]) and goto_check[i] == k1
+          return curstate
+        end
+      end
+      goto_default[k1]
+    end
+
+    # This method is called when a parse error is found.
+    #
+    # ERROR_TOKEN_ID is an internal ID of token which caused error.
+    # You can get string representation of this ID by calling
+    # #token_to_str.
+    #
+    # ERROR_VALUE is a value of error token.
+    #
+    # value_stack is a stack of symbol values.
+    # DO NOT MODIFY this object.
+    #
+    # This method raises ParseError by default.
+    #
+    # If this method returns, parsers enter "error recovering mode".
+    def on_error(t, val, vstack)
+      raise ParseError, sprintf("\nparse error on value %s (%s)",
+                                val.inspect, token_to_str(t) || '?')
+    end
+
+    # Enter error recovering mode.
+    # This method does not call #on_error.
+    def yyerror
+      throw :racc_jump, 1
+    end
+
+    # Exit parser.
+    # Return value is Symbol_Value_Stack[0].
+    def yyaccept
+      throw :racc_jump, 2
+    end
+
+    # Leave error recovering mode.
+    def yyerrok
+      @racc_error_status = 0
+    end
+
+    # For debugging output
+    def racc_read_token(t, tok, val)
+      @racc_debug_out.print 'read    '
+      @racc_debug_out.print tok.inspect, '(', racc_token2str(t), ') '
+      @racc_debug_out.puts val.inspect
+      @racc_debug_out.puts
+    end
+
+    def racc_shift(tok, tstack, vstack)
+      @racc_debug_out.puts "shift   #{racc_token2str tok}"
+      racc_print_stacks tstack, vstack
+      @racc_debug_out.puts
+    end
+
+    def racc_reduce(toks, sim, tstack, vstack)
+      out = @racc_debug_out
+      out.print 'reduce '
+      if toks.empty?
+        out.print ' <none>'
+      else
+        toks.each {|t| out.print ' ', racc_token2str(t) }
+      end
+      out.puts " --> #{racc_token2str(sim)}"
+
+      racc_print_stacks tstack, vstack
+      @racc_debug_out.puts
+    end
+
+    def racc_accept
+      @racc_debug_out.puts 'accept'
+      @racc_debug_out.puts
+    end
+
+    def racc_e_pop(state, tstack, vstack)
+      @racc_debug_out.puts 'error recovering mode: pop token'
+      racc_print_states state
+      racc_print_stacks tstack, vstack
+      @racc_debug_out.puts
+    end
+
+    def racc_next_state(curstate, state)
+      @racc_debug_out.puts  "goto    #{curstate}"
+      racc_print_states state
+      @racc_debug_out.puts
+    end
+
+    def racc_print_stacks(t, v)
+      out = @racc_debug_out
+      out.print '        ['
+      t.each_index do |i|
+        out.print ' (', racc_token2str(t[i]), ' ', v[i].inspect, ')'
+      end
+      out.puts ' ]'
+    end
+
+    def racc_print_states(s)
+      out = @racc_debug_out
+      out.print '        ['
+      s.each {|st| out.print ' ', st }
+      out.puts ' ]'
+    end
+
+    def racc_token2str(tok)
+      self.class::Racc_token_to_s_table[tok] or
+          raise "[Racc Bug] can't convert token #{tok} to string"
+    end
+
+    # Convert internal ID of token symbol to the string.
+    def token_to_str(t)
+      self.class::Racc_token_to_s_table[t]
+    end
+
+  end
+
+end
diff --git a/jni/ruby/lib/racc/rdoc/grammar.en.rdoc b/jni/ruby/lib/racc/rdoc/grammar.en.rdoc
new file mode 100644
index 0000000..a154246
--- /dev/null
+++ b/jni/ruby/lib/racc/rdoc/grammar.en.rdoc
@@ -0,0 +1,219 @@
+= Racc Grammar File Reference
+
+== Global Structure
+
+== Class Block and User Code Block
+
+There are two blocks on toplevel. One is 'class' block, another is 'user code'
+block. 'user code' block MUST be placed after 'class' block.
+
+== Comments
+
+You can insert comments about all places. Two style comments can be used, Ruby style '#.....' and C style '/\*......*\/'.
+
+== Class Block
+
+The class block is formed like this:
+
+  class CLASS_NAME
+    [precedance table]
+    [token declarations]
+    [expected number of S/R conflicts]
+    [options]
+    [semantic value convertion]
+    [start rule]
+  rule
+    GRAMMARS
+
+CLASS_NAME is a name of parser class. This is the name of generating parser
+class.
+
+If CLASS_NAME includes '::', Racc outputs module clause. For example, writing
+"class M::C" causes creating the code bellow:
+
+  module M
+    class C
+      :
+      :
+    end
+  end
+
+== Grammar Block
+
+The grammar block describes grammar which is able to be understood by parser.
+Syntax is:
+
+  (token): (token) (token) (token).... (action)
+
+  (token): (token) (token) (token).... (action)
+         | (token) (token) (token).... (action)
+         | (token) (token) (token).... (action)
+
+(action) is an action which is executed when its (token)s are found.
+(action) is a ruby code block, which is surrounded by braces:
+
+  { print val[0]
+    puts val[1] }
+
+Note that you cannot use '%' string, here document, '%r' regexp in action.
+
+Actions can be omitted. When it is omitted, '' (empty string) is used.
+
+A return value of action is a value of left side value ($$). It is value of
+result, or returned value by `return` statement.
+
+Here is an example of whole grammar block.
+
+  rule
+    goal: definition rules source { result = val }
+
+    definition: /* none */   { result = [] }
+      | definition startdesig  { result[0] = val[1] }
+      | definition
+               precrule   # this line continues from upper line
+        {
+          result[1] = val[1]
+        }
+
+    startdesig: START TOKEN
+
+You can use the following special local variables in action:
+
+* result ($$)
+
+The value of left-hand side (lhs). A default value is val[0].
+
+* val ($1,$2,$3...)
+
+An array of value of right-hand side (rhs).
+
+* _values (...$-2,$-1,$0)
+
+A stack of values. DO NOT MODIFY this stack unless you know what you are doing.
+
+== Operator Precedence
+
+This function is equal to '%prec' in yacc.
+To designate this block:
+
+  prechigh
+    nonassoc '++'
+    left     '*' '/'
+    left     '+' '-'
+    right    '='
+  preclow
+
+`right` is yacc's %right, `left` is yacc's %left.
+
+`=` + (symbol) means yacc's %prec:
+
+  prechigh
+    nonassoc UMINUS
+    left '*' '/'
+    left '+' '-'
+  preclow
+
+  rule
+    exp: exp '*' exp
+       | exp '-' exp
+       | '-' exp       =UMINUS   # equals to "%prec UMINUS"
+           :
+           :
+
+== expect
+
+Racc has bison's "expect" directive.
+
+  # Example
+
+  class MyParser
+  rule
+    expect 3
+      :
+      :
+
+This directive declares "expected" number of shift/reduce conflicts. If
+"expected" number is equal to real number of conflicts, Racc does not print
+conflict warning message.
+
+== Declaring Tokens
+
+By declaring tokens, you can avoid many meaningless bugs. If declared token
+does not exist or existing token does not decleared, Racc output warnings.
+Declaration syntax is:
+
+  token TOKEN_NAME AND_IS_THIS
+        ALSO_THIS_IS AGAIN_AND_AGAIN THIS_IS_LAST
+
+== Options
+
+You can write options for Racc command in your Racc file.
+
+  options OPTION OPTION ...
+
+Options are:
+
+* omit_action_call
+
+omits empty action call or not.
+
+* result_var
+
+uses local variable "result" or not.
+
+You can use 'no_' prefix to invert their meanings.
+
+== Converting Token Symbol
+
+Token symbols are, as default,
+
+  * naked token string in Racc file (TOK, XFILE, this_is_token, ...)
+    --> symbol (:TOK, :XFILE, :this_is_token, ...)
+  * quoted string (':', '.', '(', ...)
+    --> same string (':', '.', '(', ...)
+
+You can change this default by "convert" block.
+Here is an example:
+
+  convert
+    PLUS 'PlusClass'      # We use PlusClass for symbol of `PLUS'
+    MIN  'MinusClass'     # We use MinusClass for symbol of `MIN'
+  end
+
+We can use almost all ruby value can be used by token symbol,
+except 'false' and 'nil'.  These cause unexpected parse error.
+
+If you want to use String as token symbol, special care is required.
+For example:
+
+  convert
+    class '"cls"'            # in code, "cls"
+    PLUS '"plus\n"'          # in code, "plus\n"
+    MIN  "\"minus#{val}\""   # in code, \"minus#{val}\"
+  end
+
+== Start Rule
+
+'%start' in yacc. This changes start rule.
+
+  start real_target
+
+== User Code Block
+
+"User Code Block" is a Ruby source code which is copied to output. There are
+three user code blocks, "header" "inner" and "footer".
+
+Format of user code is like this:
+
+  ---- header
+    ruby statement
+    ruby statement
+    ruby statement
+
+  ---- inner
+    ruby statement
+       :
+       :
+
+If four '-' exist on line head, Racc treat it as beginning of user code block.
+The name of user code block must be one word.