class CodeRay::Scanners::JavaScript

def scan_tokens encoder, options
  
  state = :initial
  string_delimiter = nil
  value_expected = true
  key_expected = false
  function_expected = false
  
  until eos?
    
    case state
      
    when :initial
      
      if match = scan(/ \s+ | \\\n /x)
        value_expected = true if !value_expected && match.index(?\n)
        encoder.text_token match, :space
        
      elsif match = scan(%r! // [^\n\\]* (?: \\. [^\n\\]* )* | /\* (?: .*? \*/ | .* ) !mx)
        value_expected = true
        encoder.text_token match, :comment
        
      elsif check(/\.?\d/)
        key_expected = value_expected = false
        if match = scan(/0[xX][0-9A-Fa-f]+/)
          encoder.text_token match, :hex
        elsif match = scan(/(?>0[0-7]+)(?![89.eEfF])/)
          encoder.text_token match, :octal
        elsif match = scan(/\d+[fF]|\d*\.\d+(?:[eE][+-]?\d+)?[fF]?|\d+[eE][+-]?\d+[fF]?/)
          encoder.text_token match, :float
        elsif match = scan(/\d+/)
          encoder.text_token match, :integer
        end
        
      elsif value_expected && match = scan(/<([[:alpha:]]\w*) (?: [^\/>]*\/> | .*?<\/\1>)/xim)
        # TODO: scan over nested tags
        xml_scanner.tokenize match, :tokens => encoder
        value_expected = false
        next
        
      elsif match = scan(/ [-+*=<>?:;,!&^|(\[{~%]+ | \.(?!\d) /x)
        value_expected = true
        last_operator = match[-1]
        key_expected = (last_operator == ?{) || (last_operator == ?,)
        function_expected = false
        encoder.text_token match, :operator
        
      elsif match = scan(/ [)\]}]+ /x)
        function_expected = key_expected = value_expected = false
        encoder.text_token match, :operator
        
      elsif match = scan(/ [$a-zA-Z_][A-Za-z_0-9$]* /x)
        kind = IDENT_KIND[match]
        value_expected = (kind == :keyword) && KEYWORDS_EXPECTING_VALUE[match]
        # TODO: labels
        if kind == :ident
          if match.index(?$)  # $ allowed inside an identifier
            kind = :predefined
          elsif function_expected
            kind = :function
          elsif check(/\s*[=:]\s*function\b/)
            kind = :function
          elsif key_expected && check(/\s*:/)
            kind = :key
          end
        end
        function_expected = (kind == :keyword) && (match == 'function')
        key_expected = false
        encoder.text_token match, kind
        
      elsif match = scan(/["']/)
        if key_expected && check(KEY_CHECK_PATTERN[match])
          state = :key
        else
          state = :string
        end
        encoder.begin_group state
        string_delimiter = match
        encoder.text_token match, :delimiter
        
      elsif value_expected && (match = scan(/\//))
        encoder.begin_group :regexp
        state = :regexp
        string_delimiter = '/'
        encoder.text_token match, :delimiter
        
      elsif match = scan(/ \/ /x)
        value_expected = true
        key_expected = false
        encoder.text_token match, :operator
        
      else
        encoder.text_token getch, :error
        
      end
      
    when :string, :regexp, :key
      if match = scan(STRING_CONTENT_PATTERN[string_delimiter])
        encoder.text_token match, :content
      elsif match = scan(/["'\/]/)
        encoder.text_token match, :delimiter
        if state == :regexp
          modifiers = scan(/[gim]+/)
          encoder.text_token modifiers, :modifier if modifiers && !modifiers.empty?
        end
        encoder.end_group state
        string_delimiter = nil
        key_expected = value_expected = false
        state = :initial
      elsif state != :regexp && (match = scan(/ \\ (?: #{ESCAPE} | #{UNICODE_ESCAPE} ) /mox))
        if string_delimiter == "'" && !(match == "\\\\" || match == "\\'")
          encoder.text_token match, :content
        else
          encoder.text_token match, :char
        end
      elsif state == :regexp && match = scan(/ \\ (?: #{ESCAPE} | #{REGEXP_ESCAPE} | #{UNICODE_ESCAPE} ) /mox)
        encoder.text_token match, :char
      elsif match = scan(/\\./m)
        encoder.text_token match, :content
      elsif match = scan(/ \\ | $ /x)
        encoder.end_group state
        encoder.text_token match, :error
        key_expected = value_expected = false
        state = :initial
      else
        raise_inspect "else case \" reached; %p not handled." % peek(1), encoder
      end
      
    else
      raise_inspect 'Unknown state', encoder
      
    end
    
  end
  
  if [:string, :regexp].include? state
    encoder.end_group state
  end
  
  encoder
end