feature checkpoints
      -------------------

      o = nope
      0 = yes

      #1 = implemented in the barest sense?
      #2 = written & passing tests?
      #3 = f u l l y    o p t i m i z e d ?

      as usually occurs when programming, it's
      inevitable that the path of bugfixing will
      be /very/ nonlinear -- so this will change
      in a nonlinear manner.

      the list of features will also wax and wane.

      # 123
      - ooo : lexer
      - ooo : parser