Method: Lexer#scan

Defined in:
lib/xmk/lexer.rb

#scan ⇒ Object 



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# File 'lib/xmk/lexer.rb', line 20

def scan
  while (c = self.advance) != nil
    @start = @current
    case c
    when "#" # comment
      self.end_line
    when "+" # append/declaration
      if self.peek == "=" 
        @assignment_type = "append"
        @tokens.push(Token.new(Token::ADD, '+=', @line))
        self.advance(2)
        self.get_value(Token::VAL)
      end
    when "=" # declaration
      @assignment_type = "assign"
      @tokens.push(Token.new(Token::SET, '=', @line))
      self.advance
      self.get_value(Token::VAL)
    when "@" # target
      loop do
        c = self.advance
        c = self.handle_comment_backslash(c)
        break if self.terminates?(c)
      end
      @tokens.push(Token.new(Token::TAR, @string[@start+1 .. @current].strip,
        @line))
    when "$" # cmd
      self.get_value(Token::CMD)
    when "_" # label
      self.handle_label
    else 
      if self.terminates?(c)
        @in_label = false
        @tokens.push(Token.new(Token::LBR, c, @line))
      elsif c.match?(/[A-Z]/) # var
        loop do
          self.advance
          break unless self.peek.match?(/[A-Z_]/)
        end
        @tokens.push(Token.new(
          Token::VAR, @string[@start .. @current].strip, @line))
      elsif c.match?(/[a-z]/) # cmd / label / platform
        if @in_label # cmd
          self.get_value(Token::CMD)
        else # label || platform
          if self.find("@") # platform
            loop do
              self.advance
              break if self.peek == ":"
            end
            @tokens.push(Token.new(Token::PLAT, @string[@start .. @current],
              @line))
            parse_target = false
            loop do
              c = self.advance
              if c == "@"
                self.advance
                parse_target = true
                @start = @current
              end
              if (c == " " || self.terminates?(c)) && parse_target
                parse_target = false
                @tokens.push(Token.new(Token::TARLINK,
                  @string[@start .. @current-1], @line))
              end
              break if self.terminates?(c)
            end
          else 
            self.handle_label
          end
        end
      end
    end
  end
  @file.close
  @tokens.push(Token.new(Token::LBR, "", @line))
  @tokens.push(Token.new(Token::EOF, "end_of_file", @line))
  @tokens
end