Method: Formula#parse_tokens

Defined in:
lib/WriteExcel/formula.rb

#parse_tokens(tokens) ⇒ Object

parse_tokens()

Convert each token or token pair to its Excel ‘ptg’ equivalent.



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# File 'lib/WriteExcel/formula.rb', line 66

def parse_tokens(tokens)
  parse_str   = ''
  last_type   = ''
  modifier    = ''
  num_args    = 0
  _class      = 0
  _classary   = [1]
  args        = tokens.dup
  # A note about the class modifiers used below. In general the class,
  # "reference" or "value", of a function is applied to all of its operands.
  # However, in certain circumstances the operands can have mixed classes,
  # e.g. =VLOOKUP with external references. These will eventually be dealt
  # with by the parser. However, as a workaround the class type of a token
  # can be changed via the repeat_formula interface. Thus, a _ref2d token can
  # be changed by the user to _ref2dA or _ref2dR to change its token class.
  #
  while (!args.empty?)
    token = args.shift

    if (token == '_arg')
      num_args = args.shift
    elsif (token == '_class')
      token = args.shift
      _class = @functions[token][2]
      # If _class is undef then it means that the function isn't valid.
      exit "Unknown function #{token}() in formula\n" if _class.nil?
      _classary.push(_class)
    elsif (token == '_vol')
      parse_str = parse_str + convert_volatile()
    elsif (token == 'ptgBool')
      token = args.shift
      parse_str = parse_str + convert_bool(token)
    elsif (token == '_num')
      token = args.shift
      parse_str = parse_str + convert_number(token)
    elsif (token == '_str')
      token = args.shift
      parse_str = parse_str + convert_string(token)
    elsif (token =~ /^_ref2d/)
      modifier  = token.sub(/_ref2d/, '')
      _class      = _classary[-1]
      _class      = 0 if modifier == 'R'
      _class      = 1 if modifier == 'V'
      token      = args.shift
      parse_str = parse_str + convert_ref2d(token, _class)
    elsif (token =~ /^_ref3d/)
      modifier  = token.sub(/_ref3d/,'')
      _class      = _classary[-1]
      _class      = 0 if modifier == 'R'
      _class      = 1 if modifier == 'V'
      token      = args.shift
      parse_str = parse_str + convert_ref3d(token, _class)
    elsif (token =~ /^_range2d/)
      modifier  = token.sub(/_range2d/,'')
      _class      = _classary[-1]
      _class      = 0 if modifier == 'R'
      _class      = 1 if modifier == 'V'
      token      = args.shift
      parse_str = parse_str + convert_range2d(token, _class)
    elsif (token =~ /^_range3d/)
      modifier  = token.sub(/_range3d/,'')
      _class      = _classary[-1]
      _class      = 0 if modifier == 'R'
      _class      = 1 if modifier == 'V'
      token      = args.shift
      parse_str = parse_str + convert_range3d(token, _class)
    elsif (token == '_func')
      token = args.shift
      parse_str = parse_str + convert_function(token, num_args.to_i)
      _classary.pop
      num_args = 0 # Reset after use
    elsif @ptg[token]
      parse_str = parse_str + [@ptg[token]].pack("C")
    else
      # Unrecognised token
      return nil
    end
  end


  return parse_str
end