# File lib/parser/lexer.rb, line 10847
  def reset(reset_state=true)
    # Ragel state:
    if reset_state
      # Unit tests set state prior to resetting lexer.
      @cs     = self.class.lex_en_line_begin

      @cond   = StackState.new('cond')
      @cmdarg = StackState.new('cmdarg')
      @cond_stack   = []
      @cmdarg_stack = []
    end

    @force_utf32   = false # Set to true by some tests

    @source_pts    = nil # @source as a codepoint array

    @p             = 0   # stream position (saved manually in #advance)
    @ts            = nil # token start
    @te            = nil # token end
    @act           = 0   # next action

    @stack         = []  # state stack
    @top           = 0   # state stack top pointer

    # Lexer state:
    @token_queue   = []
    @literal_stack = []

    @eq_begin_s    = nil # location of last encountered =begin
    @sharp_s       = nil # location of last encountered #

    @newline_s     = nil # location of last encountered newline

    @num_base      = nil # last numeric base
    @num_digits_s  = nil # starting position of numeric digits
    @num_suffix_s  = nil # starting position of numeric suffix
    @num_xfrm      = nil # numeric suffix-induced transformation

    @escape_s      = nil # starting position of current sequence
    @escape        = nil # last escaped sequence, as string

    @herebody_s    = nil # starting position of current heredoc line

    # Ruby 1.9 ->() lambdas emit a distinct token if do/{ is
    # encountered after a matching closing parenthesis.
    @paren_nest    = 0
    @lambda_stack  = []

    # After encountering the closing line of <<~SQUIGGLY_HEREDOC,
    # we store the indentation level and give it out to the parser
    # on request. It is not possible to infer indentation level just
    # from the AST because escape sequences such as `\ ` or `\t` are
    # expanded inside the lexer, but count as non-whitespace for
    # indentation purposes.
    @dedent_level  = nil

    # If the lexer is in `command state' (aka expr_value)
    # at the entry to #advance, it will transition to expr_cmdarg
    # instead of expr_arg at certain points.
    @command_state = false

    # True at the end of "def foo a:"
    @in_kwarg      = false
  end