identify_number

# File lib/rdoc/parser/ruby.rb, line 1129
  def identify_number(start)
    str = start.dup

    if start == "+" or start == "-" or start == ""
      start = getc
      str << start
    end

    @lex_state = EXPR_END

    if start == "0"
      if peek(0) == "x"
        ch = getc
        str << ch
        match = /[0-9a-f_]/
      else
        match = /[0-7_]/
      end
      while ch = getc
        if ch !~ match
          ungetc
          break
        else
          str << ch
        end
      end
      return Token(TkINTEGER).set_text(str)
    end

    type = TkINTEGER
    allow_point = TRUE
    allow_e = TRUE
    while ch = getc
      case ch
      when /[0-9_]/
        str << ch

      when allow_point && "."
        type = TkFLOAT
        if peek(0) !~ /[0-9]/
          ungetc
          break
        end
        str << ch
        allow_point = false

      when allow_e && "e", allow_e && "E"
        str << ch
        type = TkFLOAT
        if peek(0) =~ /[+-]/
          str << getc
        end
        allow_e = false
        allow_point = false
      else
        ungetc
        break
      end
    end
    Token(type).set_text(str)
  end