* TODO =assert_equal_type= macro in testing
* Build-in forms

** DONE +
   CLOSED: [2018-09-18 Di 12:14]
** DONE -
   CLOSED: [2018-09-18 Di 12:14]
** DONE *
   CLOSED: [2018-09-18 Di 12:14]
** DONE /
   CLOSED: [2018-09-18 Di 12:14]
** TODO >
** TODO <
** TODO =

** DONE if
   CLOSED: [2018-09-18 Di 12:14]
** DONE and (short circuiting)
   CLOSED: [2018-10-05 Fr 22:21]
** DONE or
   CLOSED: [2018-10-05 Fr 22:21]
** DONE not
   CLOSED: [2018-10-05 Fr 22:21]
#+begin_src emacs-lisp
(not 1)                  ;; == (not . (1 . nil))
(not (expression 1 3))   ;; == (not . ((expression . (1 . (3 . nil))) . nil))
(not)                    ;; == (not . nil)
(not 1 2)                ;; == (not . (1 . (2 . nil)))
#+end_src

#+RESULTS:
: t

** TODO first  (car)
** TODO rest   (cdr)
** TODO pair   (cons)

** TODO load   (import)
** TODO define
** TODO lambda
** TODO progn
** TODO eval
** TODO quote
** TODO print
** TODO read
** TODO help

* Types
 - Symbol
 - Number
 - String
 - Cons-cell (list)
 - lambda function lambda
 - built-in function

* Arbeitsweise

 1) Parse to AST
 2) Start with namespace only containing the built-ins
 3) every AST node has its own namespace,
    inherting the one from its parent (pointer /
    references) because when a function sets a
    variable within an upper namespace it should
    infact change the environment even if the
    function exited