some things

bin/pre.slime

@@ -1,18 +1,24 @@
 (define-syntax when (condition :rest body)
-  (list 'if condition (pair 'prog body) nil))
+  ;; (break)
+  `(if ,condition ,(pair prog body) nil))
+  ;; (list 'if condition (pair 'prog body) nil))
 
 (define-syntax unless (condition :rest body)
-  (list 'if condition nil (pair 'prog 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))
@@ -52,7 +58,7 @@
 
 (defun pair? (x)
   "Checks if the argument is a pair."
-  (or (= (type x) :pair) (= (type x) :nil)))
+  (= (type x) :pair))
 
 (defun string? (x)
   "Checks if the argument is a string."
@@ -191,6 +197,11 @@ added to a list, which in the end is returned."
               (filter fun (rest seq)))
       (filter fun (rest seq)))))
 
+(defun zip (l1 l2)
+  (if (and (nil? l1) (nil? l2))
+      nil
+    (pair (list (first l1) (first l2)) (zip (rest l1) (rest l2)))))
+
 (defun 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
@@ -208,5 +219,5 @@ las argument."
 
   (eval (pair printf-quoted (extend (list :@sep (eval sep) :@end (eval end)) args))))
 
-;; (defmacro pe (@expr)
-;;   (printf @expr "evaluates to" (eval @expr)))
+(defspecial pe (@expr)
+  (printf @expr "evaluates to" (eval @expr)))