class RDoc::RubyLex

def lex_init()
  @OP = IRB::SLex.new
  @OP.def_rules("\0", "\004", "\032") do |op, io|
    Token(TkEND_OF_SCRIPT)
  end
  @OP.def_rules(" ", "\t", "\f", "\r", "\13") do |op, io|
    @space_seen = true
    str = op
    while (ch = getc) =~ /[ \t\f\r\13]/ do
      str << ch
    end
    ungetc
    Token TkSPACE, str
  end
  @OP.def_rule("#") do |op, io|
    identify_comment
  end
  @OP.def_rule("=begin",
               proc{|op, io| @prev_char_no == 0 && peek(0) =~ /\s/}) do
    |op, io|
    @ltype = "="
    res = ''
    until (ch = getc) == "\n" do res << ch end
    until peek_equal?("=end") && peek(4) =~ /\s/ do
      until (ch = getc) == "\n" do res << ch end
    end
    res << gets
    @ltype = nil
    Token(TkRD_COMMENT, res)
  end
  @OP.def_rule("\n") do |op, io|
    print "\\n\n" if RDoc::RubyLex.debug?
    case @lex_state
    when EXPR_BEG, EXPR_FNAME, EXPR_DOT
      @continue = true
    else
      @continue = false
      @lex_state = EXPR_BEG
      until (@indent_stack.empty? ||
             [TkLPAREN, TkLBRACK, TkLBRACE,
               TkfLPAREN, TkfLBRACK, TkfLBRACE].include?(@indent_stack.last))
        @indent_stack.pop
      end
    end
    @here_header = false
    @here_readed = []
    Token(TkNL)
  end
  @OP.def_rules("*", "**",
                "=", "==", "===",
                "=~", "<=>",
                "<", "<=",
                ">", ">=", ">>") do
    |op, io|
    case @lex_state
    when EXPR_FNAME, EXPR_DOT
      @lex_state = EXPR_ARG
    else
      @lex_state = EXPR_BEG
    end
    Token(op)
  end
  @OP.def_rules("!", "!=", "!~") do
    |op, io|
    @lex_state = EXPR_BEG
    Token(op)
  end
  @OP.def_rules("<<") do
    |op, io|
    tk = nil
    if @lex_state != EXPR_END && @lex_state != EXPR_CLASS &&
      (@lex_state != EXPR_ARG || @space_seen)
      c = peek(0)
      if /\S/ =~ c && (/["'`]/ =~ c || /\w/ =~ c || c == "-")
        tk = identify_here_document
      end
    end
    unless tk
      tk = Token(op)
      case @lex_state
      when EXPR_FNAME, EXPR_DOT
        @lex_state = EXPR_ARG
      else
        @lex_state = EXPR_BEG
      end
    end
    tk
  end
  @OP.def_rules("'", '"') do
    |op, io|
    identify_string(op)
  end
  @OP.def_rules("`") do
    |op, io|
    if @lex_state == EXPR_FNAME
      @lex_state = EXPR_END
      Token(op)
    else
      identify_string(op)
    end
  end
  @OP.def_rules('?') do
    |op, io|
    if @lex_state == EXPR_END
      @lex_state = EXPR_BEG
      Token(TkQUESTION)
    else
      ch = getc
      if @lex_state == EXPR_ARG && ch =~ /\s/
        ungetc
        @lex_state = EXPR_BEG;
        Token(TkQUESTION)
      else
        str = ch
        if ch == '\\'
          str << read_escape
        end
        @lex_state = EXPR_END
        str << (ch.respond_to?(:ord) ? ch.ord : ch[0])
        Token(TkINTEGER, str)
      end
    end
  end
  @OP.def_rules("&", "&&", "|", "||") do
    |op, io|
    @lex_state = EXPR_BEG
    Token(op)
  end
  @OP.def_rules("+=", "-=", "*=", "**=",
                "&=", "|=", "^=", "<<=", ">>=", "||=", "&&=") do
    |op, io|
    @lex_state = EXPR_BEG
    op =~ /^(.*)=$/
    Token(TkOPASGN, $1)
  end
  @OP.def_rule("+@", proc{|op, io| @lex_state == EXPR_FNAME}) do
    |op, io|
    @lex_state = EXPR_ARG
    Token(op)
  end
  @OP.def_rule("-@", proc{|op, io| @lex_state == EXPR_FNAME}) do
    |op, io|
    @lex_state = EXPR_ARG
    Token(op)
  end
  @OP.def_rules("+", "-") do
    |op, io|
    catch(:RET) do
      if @lex_state == EXPR_ARG
        if @space_seen and peek(0) =~ /[0-9]/
          throw :RET, identify_number
        else
          @lex_state = EXPR_BEG
        end
      elsif @lex_state != EXPR_END and peek(0) =~ /[0-9]/
        throw :RET, identify_number
      else
        @lex_state = EXPR_BEG
      end
      Token(op)
    end
  end
  @OP.def_rule(".") do
    |op, io|
    @lex_state = EXPR_BEG
    if peek(0) =~ /[0-9]/
      ungetc
      identify_number
    else
      # for "obj.if" etc.
      @lex_state = EXPR_DOT
      Token(TkDOT)
    end
  end
  @OP.def_rules("..", "...") do
    |op, io|
    @lex_state = EXPR_BEG
    Token(op)
  end
  lex_int2
end