diff --git a/.dir-locals.el b/.dir-locals.el
index 0ee656d..9d8f3e0 100644
--- a/.dir-locals.el
+++ b/.dir-locals.el
@@ -1,7 +1,4 @@
-((c++-mode . ((eval . (company-clang-set-prefix "main.cpp"))
-            (eval . (flycheck-mode 0))
-            (eval . (rainbow-mode 0))))
- (nil . ((eval . (progn
+((nil . ((eval . (progn
                    (defvar context-mode-map (make-sparse-keymap)
                      "Keymap while context-mode is active.")
                    (define-minor-mode context-mode
@@ -34,4 +31,12 @@
                      ("o" browse-file-directory                  "open"  :color blue)
                      ("q" nil                                    "quit"  :color blue))
 
-                   (define-key context-mode-map (kbd "<f2>") 'hydra-context/body))))))
+                   (define-key context-mode-map (kbd "<f2>") 'hydra-context/body)
+
+                   (font-lock-add-keywords 'c++-mode
+                                           '(("\\<\\(if_debug\\|if_windows\\|if_linux\\)\\>" .
+                                              font-lock-keyword-face)))))))
+ (c++-mode . ((eval . (company-clang-set-prefix "main.cpp"))
+              (eval . (flycheck-mode 0))
+              (eval . (rainbow-mode 0))
+              )))
diff --git a/.gitignore b/.gitignore
index ca927bf..53f182a 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,10 +1,9 @@
-/lisp
+/vs/*/*
+/build
 *.ilk
 *.pdb
 *.exe
 *.user
-/vs/*/*
-/bin/slime
 *.psess
 *.vspx
 todo.html
diff --git a/bin/pre.slime b/bin/pre.slime
new file mode 100644
index 0000000..46a06b9
--- /dev/null
+++ b/bin/pre.slime
@@ -0,0 +1,241 @@
+(define-syntax when (condition :rest body)
+  "alsdkjalsk djalksdj alksjd lakjd"
+  `(if ,condition ,(pair prog body) nil))
+
+(define-syntax unless (condition :rest body)
+  `(if ,condition nil ,(pair prog body)))
+
+;; (define-syntax defun (name arguments :rest body)
+;;   ;; (type-assert arguments :pair)
+;;   ;; `(define ,name (lambda ,arguments ,body))
+;;   ;; TODO(Felix: I think we do not need to wrap the body of the lamba
+;;   ;; in a prog
+
+;;   ;; see if we have a docstring
+;;   (if (and (= (type (first body)) :string) (not (= (type (rest body)) :nil)))
+;;       (list 'define name (list 'lambda arguments (first body) (pair 'prog (rest body))))
+;;     (list 'define name (list 'lambda arguments (pair 'prog body)))))
+
+
+;; (define-syntax defspecial (name arguments :rest body)
+;;   ;; (type-assert arguments :pair)
+;;   ;; `(define ,name (lambda ,arguments ,body))
+
+;;   ;; see if we have a docstring
+;;   (if (and (= (type (first body)) :string) (not (= (type (rest body)) :nil)))
+;;       (list 'define name (list 'special-lambda arguments (first body) (pair 'prog (rest body))))
+;;     (list 'define name (list 'special-lambda arguments (pair 'prog body)))))
+
+;; (define (fib n))
+;; (define-syntax define (name :rest value)
+;;   (print name)
+;;   (print (type name))
+;;   (if (= (type name) :pair)
+;;       (prog
+;;        ;; (print `(define ,(first name) ,`(pair lambda (pair (rest name) value))))
+;;        ;; (print rest)
+;;        (print "\naa\n")
+;;        (list 'define (first name) (pair 'lambda (pair (rest name) value))))
+;;     (prog
+;;      ;; (print (pair 'define (pair name value)))
+;;      (print "\nbb\n")
+;;      (pair 'define (pair name value)))))
+
+;; (define-syntax cond (:rest clauses)
+;;   (define (rec clauses)
+;;     (if (= nil clauses)
+;;         nil
+;;       (list 'if (first (first clauses))
+;;             (pair 'prog (rest (first clauses)))
+;;             (rec (rest clauses)))))
+;;   (rec clauses))
+
+(define (nil? x)
+  "Checks if the argument is nil."
+  (= x nil))
+
+(define (number? x)
+  "Checks if the argument is a number."
+  (= (type x) :number))
+
+(define (symbol? x)
+  "Checks if the argument is a symbol."
+  (= (type x) :symbol))
+
+(define (keyword? x)
+  "Checks if the argument is a keyword."
+  (= (type x) :keyword))
+
+(define (pair? x)
+  "Checks if the argument is a pair."
+  (= (type x) :pair))
+
+(define (string? x)
+  "Checks if the argument is a string."
+  (= (type x) :string))
+
+(define (lambda? x)
+  "Checks if the argument is a function."
+  (= (type x) :dynamic-function))
+
+(define (special-lambda? x)
+  "Checks if the argument is a macro."
+  (= (type x) :dynamic-macro))
+
+(define (built-n-function? x)
+  "Checks if the argument is a built-in function."
+  (= (type x) :built-in-function))
+
+(define (apply fun seq)
+  "Applies the funciton to the sequence, as in calls the function with
+ithe sequence as arguemens."
+  (eval (pair fun seq)))
+
+(define (end seq)
+  "Returns the last pair in the sqeuence."
+  (if (or (nil? seq) (not (pair? (rest seq))))
+      seq
+    (end (rest seq))))
+
+(define (last seq)
+  "Returns the (first) of the last (pair) of the given sequence."
+  (first (end seq)))
+
+(define (extend seq elem)
+  "Extends a list with the given element, by putting it in
+the (rest) of the last element of the sequence."
+  (if (pair? seq)
+      (prog
+        (define e (end seq))
+        (mutate e (pair (first e) elem))
+        seq)
+    elem))
+
+(define (append seq elem)
+  "Appends an element to a sequence, by extendeing the list
+with (pair elem nil)."
+  (extend seq (pair elem nil)))
+
+(define-syntax extend! (seq elem)
+  "test"
+  `(mutate ,seq (extend ,seq ,elem)))
+
+(define-syntax append! (seq elem)
+  `(mutate ,seq (append ,seq ,elem)))
+
+(define (length seq)
+  "Returns the length of the given sequence."
+  (if (nil? seq)
+      0
+    (+ 1 (length (rest seq)))))
+
+(define (increment val)
+  "Adds one to the argument."
+  (+ val 1))
+
+(define (decrement val)
+  "Subtracts one from the argument."
+  (- val 1))
+
+;; (defmacro n-times (@times @action)
+;;   "Executes @action @times times."
+;;   (unless (<= (eval @times) 0)
+;;     (eval @action)
+;;     (apply n-times (list (list - @times 1) @action))))
+
+;; (defmacro for (@symbol @from @to :rest @for-body)
+;;   "Designed to resemble a C style for loop. It takes a symbol as
+;; well as its starting number and end number and executes the
+;; @for-body with the defined symbol for all numbers between @from
+;; to @to, where @to is exclusive."
+;;   (if (< (eval @from) (eval @to))
+;;       (macro-define @op incr)
+;;     (if (> (eval @from) (eval @to))
+;;         (macro-define @op decr)
+;;       (macro-define @op nil)))
+;;   (when @op
+;;      (macro-define (eval @symbol) (eval @from))
+;;      (eval (pair prog @for-body))
+;;      (eval (extend (list for @symbol (@op @from) @to) @for-body))))
+
+(define (range :keys from :defaults-to 0 to)
+  "Returns a sequence of numbers starting with the number defined
+by the key 'from' and ends with the number defined in 'to'."
+  (when (< from to)
+      (pair from (range :from (+ 1 from) :to to))))
+
+(define (range-while :keys from :defaults-to 0 to)
+  "Returns a sequence of numbers starting with the number defined
+by the key 'from' and ends with the number defined in 'to'."
+  (define result (list (copy from)))
+  (define head result)
+  (mutate from (increment from))
+  (while (< from to)
+    (prog
+     (mutate head (pair (first head) (pair (copy from) nil)))
+     (define head (rest head))
+     (mutate from (increment from))))
+  result)
+
+(define (map fun seq)
+  "Takes a function and a sequence as arguments and returns a new
+sequence which contains the results of using the first sequences
+elemens as argument to that function."
+  (if (nil? seq)
+      seq
+    (pair (fun (first seq))
+          (map fun (rest seq)))))
+
+(define (reduce fun seq)
+  "Takes a function and a sequence as arguments and applies the
+function to the argument sequence. This only works correctly if
+the given function accepts a variable amount of parameters. If
+your funciton is limited to two arguments, use `reduce-binary'
+instead."
+  (apply fun seq))
+
+(define (reduce-binary fun seq)
+  "Takes a function and a sequence as arguments and applies the
+function to the argument sequence. reduce-binary applies the
+arguments `pair-wise' which means it works with binary functions
+as compared to `reduce'."
+  (if (nil? (rest seq))
+      (first seq)
+    (fun (first seq)
+         (reduce-binary fun (rest seq)))))
+
+(define (filter fun seq)
+  "Takes a function and a sequence as arguments and applies the
+function to every value in the sequence. If the result of that
+funciton application returns a truthy value, the original value is
+added to a list, which in the end is returned."
+  (when seq
+    (if (fun (first seq))
+        (pair (first seq)
+              (filter fun (rest seq)))
+      (filter fun (rest seq)))))
+
+(define (zip l1 l2)
+  (if (and (nil? l1) (nil? l2))
+      nil
+    (pair (list (first l1) (first l2)) (zip (rest l1) (rest l2)))))
+
+(define (printf :keys sep :defaults-to " " end :defaults-to "\n" :rest args)
+  "A wrapper for the built-in (print) that accepts a variable number
+of arguments and also provides keywords for specifying the printed
+separators between the arguments and what should be printed after the
+las argument."
+  (define printf-quoted (special-lambda (:keys @sep @end :rest @args)
+    (if (nil? @args)
+        (prog (print (eval @end)) nil)
+      (prog
+       (print (first @args))
+       (unless (nil? (rest @args))
+         (print (eval @sep)))
+       (eval (pair printf-quoted
+              (extend (list :@sep (eval @sep) :@end (eval @end)) (rest @args))))))))
+
+  (eval (pair printf-quoted (extend (list :@sep (eval sep) :@end (eval end)) args))))
+
+(define-syntax pe (expr)
+  `(printf ,expr "evaluates to" (eval ,expr)))
diff --git a/bin/pre.slime.expanded b/bin/pre.slime.expanded
new file mode 100644
index 0000000..b12fc6c
--- /dev/null
+++ b/bin/pre.slime.expanded
@@ -0,0 +1,71 @@
+(define (nil? x) "Checks if the argument is nil." (= x nil))
+
+(define (number? x) "Checks if the argument is a number." (= (type x) :number))
+
+(define (symbol? x) "Checks if the argument is a symbol." (= (type x) :symbol))
+
+(define (keyword? x) "Checks if the argument is a keyword." (= (type x) :keyword))
+
+(define (pair? x) "Checks if the argument is a pair." (= (type x) :pair))
+
+(define (string? x) "Checks if the argument is a string." (= (type x) :string))
+
+(define (lambda? x) "Checks if the argument is a function." (= (type x) :dynamic-function))
+
+(define (special-lambda? x) "Checks if the argument is a macro." (= (type x) :dynamic-macro))
+
+(define (built-n-function? x) "Checks if the argument is a built-in function." (= (type x) :built-in-function))
+
+(define (apply fun seq) "Applies the funciton to the sequence, as in calls the function with
+ithe sequence as arguemens." (eval (pair fun seq)))
+
+(define (end seq) "Returns the last pair in the sqeuence." (if (or (nil? seq) (not (pair? (rest seq)))) seq (end (rest seq))))
+
+(define (last seq) "Returns the (first) of the last (pair) of the given sequence." (first (end seq)))
+
+(define (extend seq elem) "Extends a list with the given element, by putting it in
+the (rest) of the last element of the sequence." (if (pair? seq) (prog (define e (end seq)) (mutate e (pair (first e) elem)) seq) elem))
+
+(define (append seq elem) "Appends an element to a sequence, by extendeing the list
+with (pair elem nil)." (extend seq (pair elem nil)))
+
+(define (length seq) "Returns the length of the given sequence." (if (nil? seq) 0.000000 (+ 1.000000 (length (rest seq)))))
+
+(define (increment val) "Adds one to the argument." (+ val 1.000000))
+
+(define (decrement val) "Subtracts one from the argument." (- val 1.000000))
+
+(define (range :keys from :defaults-to 0.000000 to) "Returns a sequence of numbers starting with the number defined
+by the key 'from' and ends with the number defined in 'to'." (if (< from to) ([C-function] (pair from (range :from (+ 1.000000 from) :to to))) nil))
+
+(define (range-while :keys from :defaults-to 0.000000 to) "Returns a sequence of numbers starting with the number defined
+by the key 'from' and ends with the number defined in 'to'." (define result (list (copy from))) (define head result) (mutate from (increment from)) (while (< from to) (prog (mutate head (pair (first head) (pair (copy from) nil))) (define head (rest head)) (mutate from (increment from)))) result)
+
+(define (map fun seq) "Takes a function and a sequence as arguments and returns a new
+sequence which contains the results of using the first sequences
+elemens as argument to that function." (if (nil? seq) seq (pair (fun (first seq)) (map fun (rest seq)))))
+
+(define (reduce fun seq) "Takes a function and a sequence as arguments and applies the
+function to the argument sequence. This only works correctly if
+the given function accepts a variable amount of parameters. If
+your funciton is limited to two arguments, use `reduce-binary'
+instead." (apply fun seq))
+
+(define (reduce-binary fun seq) "Takes a function and a sequence as arguments and applies the
+function to the argument sequence. reduce-binary applies the
+arguments `pair-wise' which means it works with binary functions
+as compared to `reduce'." (if (nil? (rest seq)) (first seq) (fun (first seq) (reduce-binary fun (rest seq)))))
+
+(define (filter fun seq) "Takes a function and a sequence as arguments and applies the
+function to every value in the sequence. If the result of that
+funciton application returns a truthy value, the original value is
+added to a list, which in the end is returned." (if seq ([C-function] (if (fun (first seq)) (pair (first seq) (filter fun (rest seq))) (filter fun (rest seq)))) nil))
+
+(define (zip l1 l2) (if (and (nil? l1) (nil? l2)) nil (pair (list (first l1) (first l2)) (zip (rest l1) (rest l2)))))
+
+(define (printf :keys sep :defaults-to " " end :defaults-to "
+" :rest args) "A wrapper for the built-in (print) that accepts a variable number
+of arguments and also provides keywords for specifying the printed
+separators between the arguments and what should be printed after the
+las argument." (define printf-quoted (special-lambda (:keys @sep @end :rest @args) (if (nil? @args) (prog (print (eval @end)) nil) (prog (print (first @args)) (if (nil? (rest @args)) nil ([C-function] (print (eval @sep)))) (eval (pair printf-quoted (extend (list :@sep (eval @sep) :@end (eval @end)) (rest @args)))))))) (eval (pair printf-quoted (extend (list :@sep (eval sep) :@end (eval end)) args))))
+
diff --git a/src/forward_decls.cpp b/src/forward_decls.cpp
index 8d73078..1959475 100644
--- a/src/forward_decls.cpp
+++ b/src/forward_decls.cpp
@@ -1,10 +1,10 @@
+proc assert_type(Lisp_Object*, Lisp_Object_Type) -> void;
 proc built_in_load(String*, Environment*) -> Lisp_Object*;
-proc print_environment(Environment*) -> void;
+proc create_error(Error_Type, Source_Code_Location*) -> void;
 proc eval_arguments(Lisp_Object*, Environment*, int*) -> Lisp_Object*;
 proc eval_expr(Lisp_Object*, Environment*) -> Lisp_Object*;
 proc is_truthy (Lisp_Object*, Environment*) -> bool;
 proc list_length(Lisp_Object*) -> int;
 proc load_built_ins_into_environment(Environment*) -> void;
 proc parse_argument_list(Lisp_Object*, Function*) -> void;
-proc create_error(Error_Type type, Source_Code_Location* location) -> void;
-proc assert_type(Lisp_Object* node, Lisp_Object_Type type) -> void;
+proc print_environment(Environment*) -> void;