class Sass::SCSS::StaticParser

def a_n_plus_b
  if (parity = tok(/even|odd/i))
    return parity
  end
  if tok(/[+-]?[0-9]+/)
    ss
    return true unless tok(/n/)
  else
    return unless tok(/[+-]?n/i)
  end
  ss
  return true unless tok(/[+-]/)
  ss
  @expected = "number"
  tok!(/[0-9]+/)
  true
end

def attrib
  return unless tok(/\[/)
  ss
  ns, name = attrib_name!
  ss
  op = tok(/=/) ||
       tok(INCLUDES) ||
       tok(DASHMATCH) ||
       tok(PREFIXMATCH) ||
       tok(SUFFIXMATCH) ||
       tok(SUBSTRINGMATCH)
  if op
    @expected = "identifier or string"
    ss
    val = ident || tok!(STRING)
    ss
  end
  flags = ident || tok(STRING)
  tok!(/\]/)
  Selector::Attribute.new(name, ns, op, val, flags)
end

def attrib_name!
  if (name_or_ns = ident)
    # E, E|E
    if tok(/\|(?!=)/)
      ns = name_or_ns
      name = ident
    else
      name = name_or_ns
    end
  else
    # *|E or |E
    ns = tok(/\*/) || ""
    tok!(/\|/)
    name = ident!
  end
  return ns, name
end

def class_selector
  return unless tok(/\./)
  @expected = "class name"
  Selector::Class.new(ident!)
end

def combinator
  tok(PLUS) || tok(GREATER) || tok(TILDE) || reference_combinator
end

def element_name
  ns, name = Sass::Util.destructure(qualified_name(:allow_star_name))
  return unless ns || name
  if name == '*'
    Selector::Universal.new(ns)
  else
    Selector::Element.new(name, ns)
  end
end

def id_selector
  return unless tok(/#(?!\{)/)
  @expected = "id name"
  Selector::Id.new(name!)
end

def initialize(str, filename, importer, line = 1, offset = 1, allow_parent_ref = true)
  super(str, filename, importer, line, offset)
  @allow_parent_ref = allow_parent_ref
end

def interp_ident; (s = ident) && [s]; end

def interp_string; (s = tok(STRING)) && [s]; end

def interp_uri; (s = tok(URI)) && [s]; end

def interpolation(warn_for_color = false); nil; end

def keyframes_selector
  ss
  str do
    return unless keyframes_selector_component
    ss
    while tok(/,/)
      ss
      expr!(:keyframes_selector_component)
      ss
    end
  end
end

def keyframes_selector_component
  ident || tok(PERCENTAGE)
end

def moz_document_function
  val = tok(URI) || tok(URL_PREFIX) || tok(DOMAIN) || function(false)
  return unless val
  ss
  [val]
end

def parent_selector
  return unless @allow_parent_ref && tok(/&/)
  Selector::Parent.new(name)
end

def parse_keyframes_selector
  init_scanner!
  sel = expr!(:keyframes_selector)
  expected("keyframes selector") unless @scanner.eos?
  sel
end

def parse_selector
  init_scanner!
  seq = expr!(:selector_comma_sequence)
  expected("selector") unless @scanner.eos?
  seq.line = @line
  seq.filename = @filename
  seq
end

def parse_static_at_root_query
  init_scanner!
  tok!(/\(/); ss
  type = tok!(/\b(without|with)\b/).to_sym; ss
  tok!(/:/); ss
  directives = expr!(:at_root_directive_list); ss
  tok!(/\)/)
  expected("@at-root query list") unless @scanner.eos?
  return type, directives
end

def placeholder_selector
  return unless tok(/%/)
  @expected = "placeholder name"
  Selector::Placeholder.new(ident!)
end

def prefixed_selector_pseudo
  prefix = str do
    expr = str {expr!(:a_n_plus_b)}
    ss
    return expr, nil unless tok(/of/)
    ss
  end
  return prefix, expr!(:selector_comma_sequence)
end

def pseudo
  s = tok(/::?/)
  return unless s
  @expected = "pseudoclass or pseudoelement"
  name = ident!
  if tok(/\(/)
    ss
    deprefixed = deprefix(name)
    if s == ':' && SELECTOR_PSEUDO_CLASSES.include?(deprefixed)
      sel = selector_comma_sequence
    elsif s == ':' && PREFIXED_SELECTOR_PSEUDO_CLASSES.include?(deprefixed)
      arg, sel = prefixed_selector_pseudo
    elsif s == '::' && SELECTOR_PSEUDO_ELEMENTS.include?(deprefixed)
      sel = selector_comma_sequence
    else
      arg = expr!(:declaration_value).join
    end
    tok!(/\)/)
  end
  Selector::Pseudo.new(s == ':' ? :class : :element, name, arg, sel)
end

def qualified_name(allow_star_name = false)
  name = ident || tok(/\*/) || (tok?(/\|/) && "")
  return unless name
  return nil, name unless tok(/\|/)
  return name, ident! unless allow_star_name
  @expected = "identifier or *"
  return name, ident || tok!(/\*/)
end

def reference_combinator
  return unless tok(%r{/})
  res = '/'
  ns, name = expr!(:qualified_name)
  res << ns << '|' if ns
  res << name << tok!(%r{/})
  location = " of #{@filename}" if @filename
  Sass::Util.sass_warn <<MESSAGE
ATION WARNING on line #{@line}, column #{@offset}#{location}:
ference combinator #{res} is deprecated and will be removed in a future release.
E
  res
end

def script_value; nil; end

def selector
  start_pos = source_position
  # The combinator here allows the "> E" hack
  val = combinator || simple_selector_sequence
  return unless val
  nl = str {ss}.include?("\n")
  res = []
  res << val
  res << "\n" if nl
  while (val = combinator || simple_selector_sequence)
    res << val
    res << "\n" if str {ss}.include?("\n")
  end
  seq = Selector::Sequence.new(res.compact)
  if seq.members.any? {|sseq| sseq.is_a?(Selector::SimpleSequence) && sseq.subject?}
    location = " of #{@filename}" if @filename
    Sass::Util.sass_warn <<MESSAGE
ATION WARNING on line #{start_pos.line}, column #{start_pos.offset}#{location}:
bject selector operator "!" is deprecated and will be removed in a future release.
perator has been replaced by ":has()" in the CSS spec.
ample: #{seq.subjectless}
E
  end
  seq
end

def selector_comma_sequence
  sel = selector
  return unless sel
  selectors = [sel]
  ws = ''
  while tok(/,/)
    ws << str {ss}
    next unless (sel = selector)
    selectors << sel
    if ws.include?("\n")
      selectors[-1] = Selector::Sequence.new(["\n"] + selectors.last.members)
    end
    ws = ''
  end
  Selector::CommaSequence.new(selectors)
end

def selector_string
  sel = selector
  return unless sel
  sel.to_s
end

def simple_selector_sequence
  start_pos = source_position
  e = element_name || id_selector || class_selector || placeholder_selector || attrib ||
      pseudo || parent_selector
  return unless e
  res = [e]
  # The tok(/\*/) allows the "E*" hack
  while (v = id_selector || class_selector || placeholder_selector ||
             attrib || pseudo || (tok(/\*/) && Selector::Universal.new(nil)))
    res << v
  end
  pos = @scanner.pos
  line = @line
  if (sel = str? {simple_selector_sequence})
    @scanner.pos = pos
    @line = line
    begin
      # If we see "*E", don't force a throw because this could be the
      # "*prop: val" hack.
      expected('"{"') if res.length == 1 && res[0].is_a?(Selector::Universal)
      throw_error {expected('"{"')}
    rescue Sass::SyntaxError => e
      e.message << "\n\n\"#{sel}\" may only be used at the beginning of a compound selector."
      raise e
    end
  end
  Selector::SimpleSequence.new(res, tok(/!/), range(start_pos))
end

def special_directive(name, start_pos)
  return unless %w(media import charset -moz-document).include?(name)
  super
end

def use_css_import?; true; end

def var_expr; nil; end

def variable; nil; end