class RubyParser::Legacy::RubyLexer

# File lib/ruby_parser/legacy/ruby_lexer.rb, line 124
def initialize v = 18
  self.version = v
  @lex_state = :expr_none

  self.cond   = RubyParser::Legacy::RubyParserStuff::StackState.new(:cond, $DEBUG)
  self.cmdarg = RubyParser::Legacy::RubyParserStuff::StackState.new(:cmdarg, $DEBUG)

  reset
end

# File lib/ruby_parser/legacy/ruby_lexer.rb, line 134
def arg_ambiguous
  self.warning("Ambiguous first argument. make sure.")
end

# File lib/ruby_parser/legacy/ruby_lexer.rb, line 138
def arg_state
  in_arg_state? ? :expr_arg : :expr_beg
end

# File lib/ruby_parser/legacy/ruby_lexer.rb, line 142
def beginning_of_line?
  ss.bol?
end

# File lib/ruby_parser/legacy/ruby_lexer.rb, line 1052
def check re
  ss.check re
end

# File lib/ruby_parser/legacy/ruby_lexer.rb, line 147
def comments # TODO: remove this... maybe comment_string + attr_accessor
  c = @comments.join
  @comments.clear
  c
end

# File lib/ruby_parser/legacy/ruby_lexer.rb, line 1402
def d o
  $stderr.puts o.inspect
end

# File lib/ruby_parser/legacy/ruby_lexer.rb, line 241
def dedent_string(string, width)
  characters_skipped = 0
  indentation_skipped = 0

  string.chars.each do |char|
    break if indentation_skipped >= width
    if char == ' '
      characters_skipped += 1
      indentation_skipped += 1
    elsif char == "\t"
      proposed = TAB_WIDTH * (indentation_skipped / TAB_WIDTH + 1)
      break if (proposed > width)
      characters_skipped += 1
      indentation_skipped = proposed
    end
  end
  string[characters_skipped..-1]
end

# File lib/ruby_parser/legacy/ruby_lexer.rb, line 1056
def eat_whitespace
  r = scan(/\s+/)
  self.extra_lineno += r.count("\n") if r
  r
end

# File lib/ruby_parser/legacy/ruby_lexer.rb, line 153
def end_of_stream?
  ss.eos?
end

# File lib/ruby_parser/legacy/ruby_lexer.rb, line 157
def expr_dot?
  lex_state == :expr_dot
end

# File lib/ruby_parser/legacy/ruby_lexer.rb, line 161
def expr_fname?
  lex_state == :expr_fname
end

# File lib/ruby_parser/legacy/ruby_lexer.rb, line 165
def expr_result token, text
  cond.push false
  cmdarg.push false
  result :expr_beg, token, text
end

# File lib/ruby_parser/legacy/ruby_lexer.rb, line 1062
def fixup_lineno extra = 0
  self.lineno += self.extra_lineno + extra
  self.extra_lineno = 0
end

# File lib/ruby_parser/legacy/ruby_lexer.rb, line 171
def heredoc here # TODO: rewrite / remove
  _, eos, func, last_line = here

  indent         = (func & STR_FUNC_INDENT) != 0 ? "[ \t]*" : nil
  content_indent = (func & STR_FUNC_ICNTNT) != 0
  expand         = (func & STR_FUNC_EXPAND) != 0
  eos_re         = /#{indent}#{Regexp.escape eos}(\r*\n|\z)/
  err_msg        = "can't match #{eos_re.inspect} anywhere in "

  rb_compile_error err_msg if end_of_stream?

  if beginning_of_line? && scan(eos_re) then
    self.lineno += 1
    ss.unread_many last_line # TODO: figure out how to remove this
    return :tSTRING_END, eos
  end

  self.string_buffer = []

  if expand then
    case
    when scan(/#[$@]/) then
      ss.pos -= 1 # FIX omg stupid
      return :tSTRING_DVAR, matched
    when scan(/#[{]/) then
      return :tSTRING_DBEG, matched
    when scan(/#/) then
      string_buffer << '#'
    end

    begin
      c = tokadd_string func, "\n", nil

      rb_compile_error err_msg if
        c == RubyLexer::EOF

      if c != "\n" then
        return :tSTRING_CONTENT, string_buffer.join.delete("\r")
      else
        string_buffer << scan(/\n/)
      end

      rb_compile_error err_msg if end_of_stream?
    end until check(eos_re)
  else
    until check(eos_re) do
      string_buffer << scan(/.*(\n|\z)/)
      rb_compile_error err_msg if end_of_stream?
    end
  end

  self.lex_strterm = [:heredoc, eos, func, last_line]

  string_content = string_buffer.join.delete("\r")

  string_content = heredoc_dedent(string_content) if content_indent && ruby23plus?

  return :tSTRING_CONTENT, string_content
end

# File lib/ruby_parser/legacy/ruby_lexer.rb, line 231
def heredoc_dedent(string_content)
  width = string_content.scan(/^[ \t]*(?=\S)/).map do |whitespace|
    heredoc_whitespace_indent_size whitespace
  end.min || 0

  string_content.split("\n", -1).map do |line|
    dedent_string line, width
  end.join "\n"
end

# File lib/ruby_parser/legacy/ruby_lexer.rb, line 270
def heredoc_identifier # TODO: remove / rewrite
  term, func = nil, STR_FUNC_BORING
  self.string_buffer = []

  heredoc_indent_mods = '-'
  heredoc_indent_mods += '\~' if ruby23plus?

  case
  when scan(/([#{heredoc_indent_mods}]?)([\'\"\`])(.*?)\2/) then
    term = ss[2]
    func |= STR_FUNC_INDENT unless ss[1].empty?
    func |= STR_FUNC_ICNTNT if ss[1] == '~'
    func |= case term
            when "\'" then
              STR_SQUOTE
            when '"' then
              STR_DQUOTE
            else
              STR_XQUOTE
            end
    string_buffer << ss[3]
  when scan(/[#{heredoc_indent_mods}]?([\'\"\`])(?!\1*\Z)/) then
    rb_compile_error "unterminated here document identifier"
  when scan(/([#{heredoc_indent_mods}]?)(#{IDENT_CHAR}+)/) then
    term = '"'
    func |= STR_DQUOTE
    unless ss[1].empty? then
      func |= STR_FUNC_INDENT
      func |= STR_FUNC_ICNTNT if ss[1] == '~'
    end
    string_buffer << ss[2]
  else
    return nil
  end

  if scan(/.*\n/) then
    # TODO: think about storing off the char range instead
    line = matched
  else
    line = nil
  end

  self.lex_strterm = [:heredoc, string_buffer.join, func, line]

  if term == '`' then
    result nil, :tXSTRING_BEG, "`"
  else
    result nil, :tSTRING_BEG, "\""
  end
end

# File lib/ruby_parser/legacy/ruby_lexer.rb, line 260
def heredoc_whitespace_indent_size(whitespace)
  whitespace.chars.inject 0 do |size, char|
    if char == "\t"
      size + TAB_WIDTH
    else
      size + 1
    end
  end
end

# File lib/ruby_parser/legacy/ruby_lexer.rb, line 325
def in_arg_state? # TODO: rename is_after_operator?
  in_lex_state? :expr_fname, :expr_dot
end

# File lib/ruby_parser/legacy/ruby_lexer.rb, line 321
def in_fname?
  in_lex_state? :expr_fname
end

# File lib/ruby_parser/legacy/ruby_lexer.rb, line 329
def in_lex_state?(*states)
  states.include? lex_state
end

# File lib/ruby_parser/legacy/ruby_lexer.rb, line 333
def int_with_base base
  rb_compile_error "Invalid numeric format" if matched =~ /__/

  text = matched
  case
  when text.end_with?('ri')
    return result(:expr_end, :tIMAGINARY, Complex(0, Rational(text.chop.chop.to_i(base))))
  when text.end_with?('r')
    return result(:expr_end, :tRATIONAL, Rational(text.chop.to_i(base)))
  when text.end_with?('i')
    return result(:expr_end, :tIMAGINARY, Complex(0, text.chop.to_i(base)))
  else
    return result(:expr_end, :tINTEGER, text.to_i(base))
  end
end

# File lib/ruby_parser/legacy/ruby_lexer.rb, line 349
def is_arg?
  in_lex_state?(*EXPR_ARG_ANY)
end

# File lib/ruby_parser/legacy/ruby_lexer.rb, line 353
def is_beg?
  # TODO: in_lex_state?(*EXPR_BEG_ANY) || lex_state == [:expr_arg, :expr_labeled]
  in_lex_state?(*EXPR_BEG_ANY, :expr_value, :expr_labeled)
end

# File lib/ruby_parser/legacy/ruby_lexer.rb, line 358
def is_end?
  in_lex_state?(*EXPR_END_ANY)
end

# File lib/ruby_parser/legacy/ruby_lexer.rb, line 372
def is_label_possible?
  (in_lex_state?(:expr_beg, :expr_endfn) && !cmd_state) || is_arg?
end

# File lib/ruby_parser/legacy/ruby_lexer.rb, line 376
def is_label_suffix?
  check(/:(?!:)/)
end

# File lib/ruby_parser/legacy/ruby_lexer.rb, line 380
def is_space_arg? c = "x"
  is_arg? and space_seen and c !~ /\s/
end

# File lib/ruby_parser/legacy/ruby_lexer.rb, line 384
def lambda_beginning?
  lpar_beg && lpar_beg == paren_nest
end

# File lib/ruby_parser/legacy/ruby_lexer.rb, line 1406
def lineno= n
  self.old_lineno= n
  where = caller.first.split(/:/).first(2).join(":")
  d :lineno => [n, where, ss && ss.rest[0,40]]
end

# File lib/ruby_parser/legacy/ruby_lexer.rb, line 362
def lvar_defined? id
  # TODO: (dyna_in_block? && dvar_defined?(id)) || local_id?(id)
  self.parser.env[id.to_sym] == :lvar
end

# File lib/ruby_parser/legacy/ruby_lexer.rb, line 388
def matched
  ss.matched
end

# File lib/ruby_parser/legacy/ruby_lexer.rb, line 392
def not_end?
  not is_end?
end

# File lib/ruby_parser/legacy/ruby_lexer.rb, line 1281
def parse_quote # TODO: remove / rewrite
  beg, nnd, short_hand, c = nil, nil, false, nil

  if scan(/[a-z0-9]{1,2}/i) then # Long-hand (e.g. %Q{}).
    rb_compile_error "unknown type of %string" if ss.matched_size == 2
    c, beg, short_hand = matched, ss.getch, false
  else                               # Short-hand (e.g. %{, %., %!, etc)
    c, beg, short_hand = 'Q', ss.getch, true
  end

  if end_of_stream? or c == RubyLexer::EOF or beg == RubyLexer::EOF then
    rb_compile_error "unterminated quoted string meets end of file"
  end

  # Figure nnd-char.  "\0" is special to indicate beg=nnd and that no nesting?
  nnd = { "(" => ")", "[" => "]", "{" => "}", "<" => ">" }[beg]
  nnd, beg = beg, "\0" if nnd.nil?

  token_type, text = nil, "%#{c}#{beg}"
  token_type, string_type = case c
                            when 'Q' then
                              ch = short_hand ? nnd : c + beg
                              text = "%#{ch}"
                              [:tSTRING_BEG,   STR_DQUOTE]
                            when 'q' then
                              [:tSTRING_BEG,   STR_SQUOTE]
                            when 'W' then
                              eat_whitespace
                              [:tWORDS_BEG,    STR_DQUOTE | STR_FUNC_QWORDS]
                            when 'w' then
                              eat_whitespace
                              [:tQWORDS_BEG,   STR_SQUOTE | STR_FUNC_QWORDS]
                            when 'x' then
                              [:tXSTRING_BEG,  STR_XQUOTE]
                            when 'r' then
                              [:tREGEXP_BEG,   STR_REGEXP]
                            when 's' then
                              self.lex_state  = :expr_fname
                              [:tSYMBEG,       STR_SSYM]
                            when 'I' then
                              eat_whitespace
                              [:tSYMBOLS_BEG, STR_DQUOTE | STR_FUNC_QWORDS]
                            when 'i' then
                              eat_whitespace
                              [:tQSYMBOLS_BEG, STR_SQUOTE | STR_FUNC_QWORDS]
                            end

  rb_compile_error "Bad %string type. Expected [QqWwIixrs], found '#{c}'." if
    token_type.nil?

  raise "huh" unless string_type

  string string_type, nnd, beg

  return token_type, text
end

# File lib/ruby_parser/legacy/ruby_lexer.rb, line 1338
def parse_string quote # TODO: rewrite / remove
  _, string_type, term, open = quote

  space = false # FIX: remove these
  func = string_type
  paren = open
  term_re = @@regexp_cache[term]

  qwords = (func & STR_FUNC_QWORDS) != 0
  regexp = (func & STR_FUNC_REGEXP) != 0
  expand = (func & STR_FUNC_EXPAND) != 0

  unless func then # nil'ed from qwords below. *sigh*
    return :tSTRING_END, nil
  end

  space = true if qwords and eat_whitespace

  if self.string_nest == 0 && scan(/#{term_re}/) then
    if qwords then
      quote[1] = nil
      return :tSPACE, nil
    elsif regexp then
      return :tREGEXP_END, self.regx_options
    else
      return :tSTRING_END, term
    end
  end

  return :tSPACE, nil if space

  self.string_buffer = []

  if expand
    case
    when scan(/#(?=\$(-.|[a-zA-Z_0-9~\*\$\?!@\/\\;,\.=:<>\"\&\`\'+]))/) then
      # TODO: !ISASCII
      # ?! see parser_peek_variable_name
      return :tSTRING_DVAR, nil
    when scan(/#(?=\@\@?[a-zA-Z_])/) then
      # TODO: !ISASCII
      return :tSTRING_DVAR, nil
    when scan(/#[{]/) then
      self.command_start = true
      return :tSTRING_DBEG, nil
    when scan(/#/) then
      string_buffer << '#'
    end
  end

  if tokadd_string(func, term, paren) == RubyLexer::EOF then
    rb_compile_error "unterminated string meets end of file"
  end

  return :tSTRING_CONTENT, string_buffer.join
end

# File lib/ruby_parser/legacy/ruby_lexer.rb, line 789
def possibly_escape_string text, check
  content = match[1]

  if text =~ check then
    content.gsub(ESC) { unescape $1 }
  else
    content.gsub(/\\\\/, "\\").gsub(/\\'/, "'")
  end
end

# File lib/ruby_parser/legacy/ruby_lexer.rb, line 396
def process_amper text
  token = if is_arg? && space_seen && !check(/\s/) then
             warning("`&' interpreted as argument prefix")
             :tAMPER
           elsif in_lex_state? :expr_beg, :expr_mid then
             :tAMPER
           else
             :tAMPER2
           end

  return result(:arg_state, token, "&")
end

# File lib/ruby_parser/legacy/ruby_lexer.rb, line 409
def process_backref text
  token = ss[1].to_sym
  # TODO: can't do lineno hack w/ symbol
  result :expr_end, :tBACK_REF, token
end

# File lib/ruby_parser/legacy/ruby_lexer.rb, line 415
def process_begin text
  @comments << matched

  unless scan(/.*?\n=end( |\t|\f)*[^\n]*(\n|\z)/m) then
    @comments.clear
    rb_compile_error("embedded document meets end of file")
  end

  @comments << matched
  self.lineno += matched.count("\n")

  nil # TODO
end

# File lib/ruby_parser/legacy/ruby_lexer.rb, line 429
def process_brace_close text
  # matching compare/parse23.y:8561
  cond.lexpop
  cmdarg.lexpop

  case matched
  when "}" then
    self.brace_nest -= 1
    self.lex_state   = :expr_endarg # TODO: :expr_end ? Look at 2.6

    return :tSTRING_DEND, matched if brace_nest < 0 unless ruby18 || ruby19
    return :tRCURLY, matched
  when "]" then
    self.paren_nest -= 1
    self.lex_state   = :expr_endarg
    return :tRBRACK, matched
  when ")" then
    self.paren_nest -= 1
    self.lex_state   = :expr_endfn
    return :tRPAREN, matched
  else
    raise "Unknown bracing: #{matched.inspect}"
  end
end

# File lib/ruby_parser/legacy/ruby_lexer.rb, line 478
def process_brace_open text
  # matching compare/parse23.y:8694
  self.brace_nest += 1

  if lambda_beginning? then
    self.lpar_beg = nil
    self.paren_nest -= 1 # close arg list when lambda opens body

    return expr_result(:tLAMBEG, "{")
  end

  token = case lex_state
          when :expr_labeled then
            :tLBRACE     # hash
          when *EXPR_ARG_ANY, :expr_end, :expr_endfn then
            :tLCURLY     # block (primary)
          when :expr_endarg
            :tLBRACE_ARG # block (expr)
          else
            :tLBRACE     # hash
          end

  # TODO: self.lex_state |= :expr_label if token != :tLBRACE_ARG
  self.command_start = true if token != :tLBRACE

  return expr_result(token, "{")
end

# File lib/ruby_parser/legacy/ruby_lexer.rb, line 454
def process_colon1 text
  # ?: / then / when
  if is_end? || check(/\s/) then
    return result :expr_beg, :tCOLON, text
  end

  case
  when scan(/\'/) then
    string STR_SSYM
  when scan(/\"/) then
    string STR_DSYM
  end

  result :expr_fname, :tSYMBEG, text
end

# File lib/ruby_parser/legacy/ruby_lexer.rb, line 470
def process_colon2 text
  if is_beg? || in_lex_state?(:expr_class) || is_space_arg? then
    result :expr_beg, :tCOLON3, text
  else
    result :expr_dot, :tCOLON2, text
  end
end

# File lib/ruby_parser/legacy/ruby_lexer.rb, line 506
def process_float text
  rb_compile_error "Invalid numeric format" if text =~ /__/

  case
  when text.end_with?('ri')
    return result(:expr_end, :tIMAGINARY, Complex(0, Rational(text.chop.chop)))
  when text.end_with?('r')
    return result(:expr_end, :tRATIONAL, Rational(text.chop))
  when text.end_with?('i')
    return result(:expr_end, :tIMAGINARY, Complex(0, text.chop.to_f))
  else
    return result(:expr_end, :tFLOAT, text.to_f)
  end
end

# File lib/ruby_parser/legacy/ruby_lexer.rb, line 521
def process_gvar text
  text.lineno = self.lineno
  result(:expr_end, :tGVAR, text)
end

# File lib/ruby_parser/legacy/ruby_lexer.rb, line 526
def process_gvar_oddity text
  return result :expr_end, "$", "$" if text == "$" # TODO: wtf is this?
  rb_compile_error "#{text.inspect} is not allowed as a global variable name"
end

# File lib/ruby_parser/legacy/ruby_lexer.rb, line 531
def process_ivar text
  tok_id = text =~ /^@@/ ? :tCVAR : :tIVAR
  text.lineno = self.lineno
  return result(:expr_end, tok_id, text)
end

# File lib/ruby_parser/legacy/ruby_lexer.rb, line 825
def process_label text
  symbol = possibly_escape_string text, /^"/

  result(:expr_labeled, :tLABEL, [symbol, self.lineno]) # TODO: expr_arg|expr_labeled
end

# File lib/ruby_parser/legacy/ruby_lexer.rb, line 813
def process_label_or_string text
  if @was_label && text =~ /:\Z/ then
    @was_label = nil
    return process_label text
  elsif text =~ /:\Z/ then
    ss.pos -= 1 # put back ":"
    text = text[0..-2]
  end

  result :expr_end, :tSTRING, text[1..-2].gsub(/\\\\/, "\\").gsub(/\\'/, "'")
end

# File lib/ruby_parser/legacy/ruby_lexer.rb, line 537
def process_lchevron text
  if (!in_lex_state?(:expr_dot, :expr_class) &&
      !is_end? &&
      (!is_arg? || space_seen)) then # TODO: || in_state(:expr_labeled)
    tok = self.heredoc_identifier
    return tok if tok
  end

  if in_arg_state? then
    self.lex_state = :expr_arg
  else
    self.command_start = true if lex_state == :expr_class
    self.lex_state = :expr_beg
  end

  return result(lex_state, :tLSHFT, "\<\<")
end

# File lib/ruby_parser/legacy/ruby_lexer.rb, line 555
def process_newline_or_comment text
  c = matched
  hit = false

  if c == '#' then
    ss.pos -= 1

    # TODO: handle magic comments
    while scan(/\s*\#.*(\n+|\z)/) do
      hit = true
      self.lineno += matched.lines.to_a.size
      @comments << matched.gsub(/^ +#/, '#').gsub(/^ +$/, '')
    end

    return nil if end_of_stream?
  end

  self.lineno += 1 unless hit

  # Replace a string of newlines with a single one
  self.lineno += matched.lines.to_a.size if scan(/\n+/)

  # TODO: remove :expr_value -- audit all uses of it
  c = in_lex_state?(:expr_beg, :expr_value, :expr_class,
                    :expr_fname, :expr_dot) && !in_lex_state?(:expr_labeled)

  # TODO: figure out what token_seen is for
  # TODO: if c || self.lex_state == [:expr_beg, :expr_labeled] then
  if c || self.lex_state == :expr_labeled then
    # ignore if !fallthrough?
    if !c && parser.in_kwarg then
      # normal newline
      return result(:expr_beg, :tNL, nil)
    else
      return # skip
    end
  end

  if scan(/([\ \t\r\f\v]*)(\.|&)/) then
    self.space_seen = true unless ss[1].empty?

    ss.pos -= 1
    return unless check(/\.\./)
  end

  self.command_start = true

  return result(:expr_beg, :tNL, nil)
end

# File lib/ruby_parser/legacy/ruby_lexer.rb, line 605
def process_nthref text
  # TODO: can't do lineno hack w/ number
  result :expr_end, :tNTH_REF, ss[1].to_i
end

# File lib/ruby_parser/legacy/ruby_lexer.rb, line 610
def process_paren text
  token = if ruby18 then
            process_paren18
          else
            process_paren19
          end

  self.paren_nest += 1

  # TODO: add :expr_label to :expr_beg (set in expr_result below)
  return expr_result(token, "(")
end

# File lib/ruby_parser/legacy/ruby_lexer.rb, line 623
def process_paren18
  self.command_start = true
  token = :tLPAREN2

  if in_lex_state? :expr_beg, :expr_mid then
    token = :tLPAREN
  elsif space_seen then
    if in_lex_state? :expr_cmdarg then
      token = :tLPAREN_ARG
    elsif in_lex_state? :expr_arg then
      warning "don't put space before argument parentheses"
    end
  else
    # not a ternary -- do nothing?
  end

  token
end

# File lib/ruby_parser/legacy/ruby_lexer.rb, line 642
def process_paren19
  if is_beg? then
    :tLPAREN
  elsif is_space_arg? then
    :tLPAREN_ARG
  else
    :tLPAREN2 # plain '(' in parse.y
  end
end

# File lib/ruby_parser/legacy/ruby_lexer.rb, line 652
def process_percent text
  return parse_quote if is_beg?

  return result(:expr_beg, :tOP_ASGN, "%") if scan(/\=/)

  return parse_quote if is_arg? && space_seen && ! check(/\s/)

  return result(:arg_state, :tPERCENT, "%")
end

# File lib/ruby_parser/legacy/ruby_lexer.rb, line 662
def process_plus_minus text
  sign = matched
  utype, type = if sign == "+" then
                  [:tUPLUS, :tPLUS]
                else
                  [:tUMINUS, :tMINUS]
                end

  if in_arg_state? then
    if scan(/@/) then
      return result(:expr_arg, utype, "#{sign}@")
    else
      return result(:expr_arg, type, sign)
    end
  end

  return result(:expr_beg, :tOP_ASGN, sign) if scan(/\=/)

  if (is_beg? || (is_arg? && space_seen && !check(/\s/))) then
    arg_ambiguous if is_arg?

    if check(/\d/) then
      return nil if utype == :tUPLUS
      return result(:expr_beg, :tUMINUS_NUM, sign)
    end

    return result(:expr_beg, utype, sign)
  end

  return result(:expr_beg, type, sign)
end

# File lib/ruby_parser/legacy/ruby_lexer.rb, line 694
def process_questionmark text
  if is_end? then
    state = ruby18 ? :expr_beg : :expr_value # HACK?
    return result(state, :tEH, "?")
  end

  if end_of_stream? then
    rb_compile_error "incomplete character syntax: parsed #{text.inspect}"
  end

  if check(/\s|\v/) then
    unless is_arg? then
      c2 = { " " => 's',
            "\n" => 'n',
            "\t" => 't',
            "\v" => 'v',
            "\r" => 'r',
            "\f" => 'f' }[matched]

      if c2 then
        warning("invalid character syntax; use ?\\" + c2)
      end
    end

    # ternary
    state = ruby18 ? :expr_beg : :expr_value # HACK?
    return result(state, :tEH, "?")
  elsif check(/\w(?=\w)/) then # ternary, also
    return result(:expr_beg, :tEH, "?")
  end

  c = if scan(/\\/) then
        self.read_escape
      else
        ss.getch
      end

  if version == 18 then
    return result(:expr_end, :tINTEGER, c[0].ord & 0xff)
  else
    return result(:expr_end, :tSTRING, c)
  end
end

# File lib/ruby_parser/legacy/ruby_lexer.rb, line 738
def process_slash text
  if is_beg? then
    string STR_REGEXP

    return result(nil, :tREGEXP_BEG, "/")
  end

  if scan(/\=/) then
    return result(:expr_beg, :tOP_ASGN, "/")
  end

  if is_arg? && space_seen then
    unless scan(/\s/) then
      arg_ambiguous
      string STR_REGEXP, "/"
      return result(nil, :tREGEXP_BEG, "/")
    end
  end

  return result(:arg_state, :tDIVIDE, "/")
end

# File lib/ruby_parser/legacy/ruby_lexer.rb, line 760
def process_square_bracket text
  self.paren_nest += 1

  token = nil

  if in_arg_state? then
    case
    when scan(/\]\=/) then
      self.paren_nest -= 1 # HACK? I dunno, or bug in MRI
      return result(:expr_arg, :tASET, "[]=")
    when scan(/\]/) then
      self.paren_nest -= 1 # HACK? I dunno, or bug in MRI
      return result(:expr_arg, :tAREF, "[]")
    else
      rb_compile_error "unexpected '['"
    end
  elsif is_beg? then
    token = :tLBRACK
  elsif is_arg? && space_seen then
    token = :tLBRACK
  else
    token = :tLBRACK2
  end

  # TODO: this is done by expr_result except "|EXPR_LABEL")
  # SET_LEX_STATE(EXPR_BEG|EXPR_LABEL);
  expr_result token, "["
end

# File lib/ruby_parser/legacy/ruby_lexer.rb, line 1252
def process_string # TODO: rewrite / remove
  # matches top of parser_yylex in compare/parse23.y:8113
  token = if lex_strterm[0] == :heredoc then
            self.heredoc lex_strterm
          else
            self.parse_string lex_strterm
          end

  token_type, c = token

  # matches parser_string_term
  if ruby22plus? && token_type == :tSTRING_END && ["'", '"'].include?(c) then
    if (([:expr_beg, :expr_endfn].include?(lex_state) &&
         !cond.is_in_state) || is_arg?) &&
        is_label_suffix? then
      scan(/:/)
      token_type = token[0] = :tLABEL_END
    end
  end

  if [:tSTRING_END, :tREGEXP_END, :tLABEL_END].include? token_type then
    self.lex_strterm = nil
    # TODO: :expr_beg|:expr_label
    self.lex_state   = (token_type == :tLABEL_END) ? :expr_label : :expr_end
  end

  return token
end

# File lib/ruby_parser/legacy/ruby_lexer.rb, line 799
def process_symbol text
  symbol = possibly_escape_string text, /^:"/

  rb_compile_error "symbol cannot contain '\\0'" if
    ruby18 && symbol =~ /\0/

  return result(:expr_end, :tSYMBOL, symbol)
end

# File lib/ruby_parser/legacy/ruby_lexer.rb, line 831
def process_token text
  # matching: parse_ident in compare/parse23.y:7989
  # TODO: make this always return [token, lineno]
  self.last_state = lex_state

  token = self.token = text
  token << matched if scan(/[\!\?](?!=)/)

  tok_id =
    case
    when token =~ /[!?]$/ then
      :tFID
    when in_lex_state?(:expr_fname) && scan(/=(?:(?![~>=])|(?==>))/) then
      # ident=, not =~ => == or followed by =>
      # TODO test lexing of a=>b vs a==>b
      token << matched
      :tIDENTIFIER
    when token =~ /^[A-Z]/ then
      :tCONSTANT
    else
      :tIDENTIFIER
    end

  if !ruby18 and is_label_possible? and is_label_suffix? then
    scan(/:/)
    # TODO: :expr_arg|:expr_labeled
    return result :expr_labeled, :tLABEL, [token, self.lineno]
  end

  # TODO: mb == ENC_CODERANGE_7BIT && !in_lex_state?(:expr_dot)
  unless in_lex_state? :expr_dot then
    # See if it is a reserved word.
    keyword = if ruby18 then # REFACTOR need 18/19 lexer subclasses
                RubyParser::Legacy::RubyParserStuff::Keyword.keyword18 token
              else
                RubyParser::Legacy::RubyParserStuff::Keyword.keyword19 token
              end

    return process_token_keyword keyword if keyword
  end # unless in_lex_state? :expr_dot

  # matching: compare/parse23.y:8079
  state = if is_beg? or is_arg? or in_lex_state? :expr_dot then
            cmd_state ? :expr_cmdarg : :expr_arg
          elsif not ruby18 and in_lex_state? :expr_fname then
            :expr_endfn
          else
            :expr_end
          end

  if not [:expr_dot, :expr_fname].include? last_state and
      (tok_id == :tIDENTIFIER) and # not :expr_fname, not attrasgn
      lvar_defined?(token) then
    state = :expr_end # TODO: EXPR_END|EXPR_LABEL
  end

  token.lineno = self.lineno # yes, on a string. I know... I know...

  return result(state, tok_id, token)
end

# File lib/ruby_parser/legacy/ruby_lexer.rb, line 892
def process_token_keyword keyword
  # matching MIDDLE of parse_ident in compare/parse23.y:8046
  state = lex_state
  self.lex_state = keyword.state

  value = [token, self.lineno]

  return result(lex_state, keyword.id0, value) if state == :expr_fname

  self.command_start = true if lex_state == :expr_beg

  case
  when keyword.id0 == :kDO then
    case
    when lambda_beginning? then
      self.lpar_beg = nil # lambda_beginning? == FALSE in the body of "-> do ... end"
      self.paren_nest -= 1
      result(lex_state, :kDO_LAMBDA, value)
    when cond.is_in_state then
      result(lex_state, :kDO_COND, value)
    when cmdarg.is_in_state && state != :expr_cmdarg then
      result(lex_state, :kDO_BLOCK, value)
    when [:expr_beg, :expr_endarg].include?(state) then
      result(lex_state, :kDO_BLOCK, value)
    else
      result(lex_state, :kDO, value)
    end
  when [:expr_beg, :expr_labeled].include?(state) then
    result(lex_state, keyword.id0, value)
  when keyword.id0 != keyword.id1 then
    result(:expr_beg, keyword.id1, value) # TODO: :expr_beg|:expr_label
  else
    result(lex_state, keyword.id1, value)
  end
end

# File lib/ruby_parser/legacy/ruby_lexer.rb, line 928
def process_underscore text
  ss.unscan # put back "_"

  if beginning_of_line? && scan(/\__END__(\r?\n|\Z)/) then
    return [RubyLexer::EOF, RubyLexer::EOF]
  elsif scan(/\_\w*/) then
    return process_token matched
  end
end

# File lib/ruby_parser/legacy/ruby_lexer.rb, line 938
def rb_compile_error msg
  msg += ". near line #{self.lineno}: #{ss.rest[/^.*/].inspect}"
  raise RubyParser::SyntaxError, msg
end

# File lib/ruby_parser/legacy/ruby_lexer.rb, line 943
def read_escape # TODO: remove / rewrite
  case
  when scan(/\\/) then                  # Backslash
    '\\'
  when scan(/n/) then                   # newline
    self.extra_lineno -= 1
    "\n"
  when scan(/t/) then                   # horizontal tab
    "\t"
  when scan(/r/) then                   # carriage-return
    "\r"
  when scan(/f/) then                   # form-feed
    "\f"
  when scan(/v/) then                   # vertical tab
    "\13"
  when scan(/a/) then                   # alarm(bell)
    "\007"
  when scan(/e/) then                   # escape
    "\033"
  when scan(/b/) then                   # backspace
    "\010"
  when scan(/s/) then                   # space
    " "
  when scan(/[0-7]{1,3}/) then          # octal constant
    (matched.to_i(8) & 0xFF).chr
  when scan(/x([0-9a-fA-F]{1,2})/) then # hex constant
    ss[1].to_i(16).chr
  when check(/M-\\[\\MCc]/) then
    scan(/M-\\/) # eat it
    c = self.read_escape
    c[0] = (c[0].ord | 0x80).chr
    c
  when scan(/M-(.)/) then
    c = ss[1]
    c[0] = (c[0].ord | 0x80).chr
    c
  when check(/(C-|c)\\[\\MCc]/) then
    scan(/(C-|c)\\/) # eat it
    c = self.read_escape
    c[0] = (c[0].ord & 0x9f).chr
    c
  when scan(/C-\?|c\?/) then
    127.chr
  when scan(/(C-|c)(.)/) then
    c = ss[2]
    c[0] = (c[0].ord & 0x9f).chr
    c
  when scan(/^[89]/i) then # bad octal or hex... MRI ignores them :(
    matched
  when scan(/u([0-9a-fA-F]{2,4}|\{[0-9a-fA-F]{2,6}\})/) then
    [ss[1].delete("{}").to_i(16)].pack("U")
  when scan(/[McCx0-9]/) || end_of_stream? then
    rb_compile_error("Invalid escape character syntax")
  else
    ss.getch
  end.dup
end

# File lib/ruby_parser/legacy/ruby_lexer.rb, line 1001
def regx_options # TODO: rewrite / remove
  good, bad = [], []

  if scan(/[a-z]+/) then
    good, bad = matched.split(//).partition { |s| s =~ /^[ixmonesu]$/ }
  end

  unless bad.empty? then
    rb_compile_error("unknown regexp option%s - %s" %
                     [(bad.size > 1 ? "s" : ""), bad.join.inspect])
  end

  return good.join
end

# File lib/ruby_parser/legacy/ruby_lexer.rb, line 1016
def reset
  self.brace_nest    = 0
  self.command_start = true
  self.comments      = []
  self.lex_state     = :expr_none
  self.lex_strterm   = nil
  self.lineno        = 1
  self.lpar_beg      = nil
  self.paren_nest    = 0
  self.space_seen    = false
  self.string_nest   = 0
  self.token         = nil
  self.extra_lineno  = 0

  self.cond.reset
  self.cmdarg.reset
end

# File lib/ruby_parser/legacy/ruby_lexer.rb, line 1040
def ruby18
  RubyParser::V18 === parser
end

# File lib/ruby_parser/legacy/ruby_lexer.rb, line 1044
def ruby19
  RubyParser::V19 === parser
end

# File lib/ruby_parser/legacy/ruby_lexer.rb, line 368
def ruby22_label?
  ruby22plus? and is_label_possible?
end

# File lib/ruby_parser/legacy/ruby_lexer.rb, line 1244
def ruby22plus?
  parser.class.version >= 22
end

# File lib/ruby_parser/legacy/ruby_lexer.rb, line 1248
def ruby23plus?
  parser.class.version >= 23
end

# File lib/ruby_parser/legacy/ruby_lexer.rb, line 1048
def scan re
  ss.scan re
end

# File lib/ruby_parser/legacy/ruby_lexer.rb, line 1067
def scanner_class # TODO: design this out of oedipus_lex. or something.
  RPStringScanner
end

# File lib/ruby_parser/legacy/ruby_lexer.rb, line 1071
def space_vs_beginning space_type, beg_type, fallback
  if is_space_arg? check(/./m) then
    warning "`**' interpreted as argument prefix"
    space_type
  elsif is_beg? then
    beg_type
  else
    # TODO: warn_balanced("**", "argument prefix");
    fallback
  end
end

# File lib/ruby_parser/legacy/ruby_lexer.rb, line 1083
def string type, beg = matched, nnd = "\0"
  self.lex_strterm = [:strterm, type, beg, nnd]
end

# File lib/ruby_parser/legacy/ruby_lexer.rb, line 1093
def tokadd_escape term # TODO: rewrite / remove
  case
  when scan(/\\\n/) then
    # just ignore
  when scan(/\\([0-7]{1,3}|x[0-9a-fA-F]{1,2})/) then
    self.string_buffer << matched
  when scan(/\\([MC]-|c)(?=\\)/) then
    self.string_buffer << matched
    self.tokadd_escape term
  when scan(/\\([MC]-|c)(.)/) then
    self.string_buffer << matched
  when scan(/\\[McCx]/) then
    rb_compile_error "Invalid escape character syntax"
  when scan(/\\(.)/m) then
    chr = ss[1]
    prev = self.string_buffer.last
    if term == chr && prev && prev.end_with?("(?") then
      self.string_buffer << chr
    else
      self.string_buffer << matched
    end
  else
    rb_compile_error "Invalid escape character syntax"
  end
end

# File lib/ruby_parser/legacy/ruby_lexer.rb, line 1119
def tokadd_string(func, term, paren) # TODO: rewrite / remove
  qwords = (func & STR_FUNC_QWORDS) != 0
  escape = (func & STR_FUNC_ESCAPE) != 0
  expand = (func & STR_FUNC_EXPAND) != 0
  regexp = (func & STR_FUNC_REGEXP) != 0
  symbol = (func & STR_FUNC_SYMBOL) != 0

  paren_re = @@regexp_cache[paren]
  term_re  = @@regexp_cache[term]

  until end_of_stream? do
    c = nil
    handled = true

    case
    when paren_re && scan(paren_re) then
      self.string_nest += 1
    when scan(term_re) then
      if self.string_nest == 0 then
        ss.pos -= 1
        break
      else
        self.string_nest -= 1
      end
    when expand && scan(/#(?=[\$\@\{])/) then
      ss.pos -= 1
      break
    when qwords && scan(/\s/) then
      ss.pos -= 1
      break
    when expand && scan(/#(?!\n)/) then
      # do nothing
    when check(/\\/) then
      case
      when qwords && scan(/\\\n/) then
        string_buffer << "\n"
        next
      when qwords && scan(/\\\s/) then
        c = ' '
      when expand && scan(/\\\n/) then
        next
      when regexp && check(/\\/) then
        self.tokadd_escape term
        next
      when expand && scan(/\\/) then
        c = self.read_escape
      when scan(/\\\n/) then
        # do nothing
      when scan(/\\\\/) then
        string_buffer << '\\' if escape
        c = '\\'
      when scan(/\\/) then
        unless scan(term_re) || paren.nil? || scan(paren_re) then
          string_buffer << "\\"
        end
      else
        handled = false
      end # inner /\\/ case
    else
      handled = false
    end # top case

    unless handled then
      t = Regexp.escape term
      x = Regexp.escape(paren) if paren && paren != "\000"
      re = if qwords then
             if HAS_ENC then
               /[^#{t}#{x}\#\0\\\s]+|./ # |. to pick up whatever
             else
               /[^#{t}#{x}\#\0\\\s\v]+|./ # argh. 1.8's \s doesn't pick up \v
             end
           else
             /[^#{t}#{x}\#\0\\]+|./
           end

      scan re
      c = matched

      rb_compile_error "symbol cannot contain '\\0'" if symbol && c =~ /\0/
    end # unless handled

    c ||= matched
    string_buffer << c
  end # until

  c ||= matched
  c = RubyLexer::EOF if end_of_stream?

  return c
end

# File lib/ruby_parser/legacy/ruby_lexer.rb, line 1210
def unescape s
  r = ESCAPES[s]

  self.extra_lineno += 1 if s == "\n"     # eg backslash newline strings
  self.extra_lineno -= 1 if r && s == "n" # literal \n, not newline

  return r if r

  x = case s
      when /^[0-7]{1,3}/ then
        ($&.to_i(8) & 0xFF).chr
      when /^x([0-9a-fA-F]{1,2})/ then
        $1.to_i(16).chr
      when /^M-(.)/ then
        ($1[0].ord | 0x80).chr
      when /^(C-|c)(.)/ then
        ($2[0].ord & 0x9f).chr
      when /^[89a-f]/i then # bad octal or hex... ignore? that's what MRI does :(
        s
      when /^[McCx0-9]/ then
        rb_compile_error("Invalid escape character syntax")
      when /u([0-9a-fA-F]{2,4}|\{[0-9a-fA-F]{2,6}\})/ then
        [$1.delete("{}").to_i(16)].pack("U")
      else
        s
      end
  x.force_encoding "UTF-8" if HAS_ENC
  x
end

# File lib/ruby_parser/legacy/ruby_lexer.rb, line 1240
def warning s
  # do nothing for now
end

# File lib/ruby_parser/legacy/ruby_lexer.rb, line 808
def was_label?
  @was_label = ruby22_label?
  true
end