Class: KDL::Tokenizer

Inherits:
Object
  • Object
show all
Defined in:
lib/kdl/tokenizer.rb

Defined Under Namespace

Classes: Error, Token

Constant Summary collapse

SYMBOLS = 
{
  '{' => :LBRACE,
  '}' => :RBRACE,
  '=' => :EQUALS,
  '＝' => :EQUALS,
  ';' => :SEMICOLON
}
WHITEPACE = 
["\u0009", "\u0020", "\u00A0", "\u1680",
"\u2000", "\u2001", "\u2002", "\u2003",
"\u2004", "\u2005", "\u2006", "\u2007",
"\u2008", "\u2009", "\u200A", "\u202F",
"\u205F", "\u3000" ]
NEWLINES = 
["\u000A", "\u0085", "\u000C", "\u2028", "\u2029"]
NON_IDENTIFIER_CHARS = 
Regexp.escape "#{SYMBOLS.keys.join('')}()/\\<>[]\","
IDENTIFIER_CHARS = 
/[^#{NON_IDENTIFIER_CHARS}\x0-\x20]/
INITIAL_IDENTIFIER_CHARS = 
/[^#{NON_IDENTIFIER_CHARS}0-9\x0-\x20]/
ALLOWED_IN_TYPE = 
[:ident, :string, :rawstring]
NOT_ALLOWED_AFTER_TYPE = 
[:single_line_comment, :multi_line_comment]

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(str, start = 0) ⇒ Tokenizer

Returns a new instance of Tokenizer.



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# File 'lib/kdl/tokenizer.rb', line 59

def initialize(str, start = 0)
  @str = str
  @context = nil
  @rawstring_hashes = nil
  @index = start
  @buffer = ""
  @done = false
  @previous_context = nil
  @line = 1
  @column = 1
  @type_context = false
  @last_token = nil
end

Instance Attribute Details

#index ⇒ Object (readonly)

Returns the value of attribute index.



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# File 'lib/kdl/tokenizer.rb', line 34

def index
  @index
end

Instance Method Details

#next_token ⇒ Object 



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# File 'lib/kdl/tokenizer.rb', line 73

def next_token
  @context = nil
  @previous_context = nil
  @line_at_start = @line
  @column_at_start = @column
  loop do
    c = @str[@index]
    case @context
    when nil
      case c
      when '"'
        self.context = :string
        @buffer = ''
        traverse(1)
      when 'r'
        if @str[@index + 1] == '"'
          self.context = :rawstring
          traverse(2)
          @rawstring_hashes = 0
          @buffer = ''
          next
        elsif @str[@index + 1] == '#'
          i = @index + 1
          @rawstring_hashes = 0
          while @str[i] == '#'
            @rawstring_hashes += 1
            i += 1
          end
          if @str[i] == '"'
            self.context = :rawstring
            @index = i + 1
            @buffer = ''
            next
          end
        end
        self.context = :ident
        @buffer = c
        traverse(1)
      when /[0-9\-+]/
        n = @str[@index + 1]
        if c == '0' && n =~ /[box]/
          traverse(2)
          @buffer = ''
          self.context = integer_context(n)
        elsif c == '-' && n == '0' && (n2 = @str[@index + 2]) =~ /[box]/
          traverse(3)
          @buffer = '-'
          self.context = integer_context(n2)
        else
          self.context = :decimal
          @buffer = c
          traverse(1)
        end
      when '\\'
        t = Tokenizer.new(@str, @index + 1)
        la = t.next_token
        if la[0] == :NEWLINE || la[0] == :EOF || (la[0] == :WS && (lan = t.next_token[0]) == :NEWLINE || lan == :EOF)
          @index = t.index
          new_line
          return token(:ESCLINE, "\\#{la[1].value}")
        else
          raise_error "Unexpected '\\' (#{la[0]})"
        end
      when *SYMBOLS.keys
        return token(SYMBOLS[c], c).tap { traverse(1) }
      when "\r"
        n = @str[@index + 1]
        if n == "\n"
          return token(:NEWLINE, "#{c}#{n}").tap do
            traverse(2)
            new_line
          end
        else
          return token(:NEWLINE, c).tap do
            traverse(1)
            new_line
          end
        end
      when *NEWLINES
        return token(:NEWLINE, c).tap do
          traverse(1)
          new_line
        end
      when "/"
        if @str[@index + 1] == '/'
          self.context = :single_line_comment
          traverse(2)
        elsif @str[@index + 1] == '*'
          self.context = :multi_line_comment
          @comment_nesting = 1
          traverse(2)
        elsif @str[@index + 1] == '-'
          return token(:SLASHDASH, '/-').tap { traverse(2) }
        else
          self.context = :ident
          @buffer = c
          traverse(1)
        end
      when *WHITEPACE
        self.context = :whitespace
        @buffer = c
        traverse(1)
      when nil
        return [false, token(:EOF, :EOF)[1]] if @done
        @done = true
        return token(:EOF, :EOF)
      when INITIAL_IDENTIFIER_CHARS
        self.context = :ident
        @buffer = c
        traverse(1)
      when '('
        @type_context = true
        return token(:LPAREN, c).tap { traverse(1) }
      when ')'
        @type_context = false
        return token(:RPAREN, c).tap { traverse(1) }
      else
        raise_error "Unexpected character #{c.inspect}"
      end
    when :ident
      case c
      when IDENTIFIER_CHARS
        traverse(1)
        @buffer += c
      else
        case @buffer
        when 'true'  then return token(:TRUE, true)
        when 'false' then return token(:FALSE, false)
        when 'null'  then return token(:NULL, nil)
        else return token(:IDENT, @buffer)
        end
      end
    when :string
      case c
      when '\\'
        @buffer += c
        @buffer += @str[@index + 1]
        traverse(2)
      when '"'
        return token(:STRING, convert_escapes(@buffer)).tap { traverse(1) }
      when nil
        raise_error "Unterminated string literal"
      else
        @buffer += c
        traverse(1)
      end
    when :rawstring
      raise_error "Unterminated rawstring literal" if c.nil?

      if c == '"'
        h = 0
        while @str[@index + 1 + h] == '#' && h < @rawstring_hashes
          h += 1
        end
        if h == @rawstring_hashes
          return token(:RAWSTRING, @buffer).tap { traverse(1 + h) }
        end
      end

      @buffer += c
      traverse(1)
    when :decimal
      case c
      when /[0-9.\-+_eE]/
        traverse(1)
        @buffer += c
      else
        return parse_decimal(@buffer)
      end
    when :hexadecimal
      case c
      when /[0-9a-fA-F_]/
        traverse(1)
        @buffer += c
      else
        return parse_hexadecimal(@buffer)
      end
    when :octal
      case c
      when /[0-7_]/
        traverse(1)
        @buffer += c
      else
        return parse_octal(@buffer)
      end
    when :binary
      case c
      when /[01_]/
        traverse(1)
        @buffer += c
      else
        return parse_binary(@buffer)
      end
    when :single_line_comment
      if NEWLINES.include?(c) || c == "\r"
        self.context = nil
        @column_at_start = @column
        next
      elsif c.nil?
        @done = true
        return token(:EOF, :EOF)
      else
        traverse(1)
      end
    when :multi_line_comment
      if c == '/' && @str[@index + 1] == '*'
        @comment_nesting += 1
        traverse(2)
      elsif c == '*' && @str[@index + 1] == '/'
        @comment_nesting -= 1
        traverse(2)
        if @comment_nesting == 0
          revert_context
        end
      else
        traverse(1)
      end
    when :whitespace
      if WHITEPACE.include?(c)
        traverse(1)
        @buffer += c
      elsif c == "/" && @str[@index + 1] == '*'
        self.context = :multi_line_comment
        @comment_nesting = 1
        traverse(2)
      else
        return token(:WS, @buffer)
      end
    end
  end
end