if-not and when-not

d-.scm

@@ -3,6 +3,8 @@
   #:export
   (~>
    ~>>
+   if-not
+   when-not
    partial
    argmin))
 
@@ -18,6 +20,12 @@
     [(_ v (fn args ...) more ...) (~> (fn args ... v) more ...)]
     [(_ v fn more ...) (~> (fn v) more ...)]))
 
+(define-syntax-rule (if-not pred body ...)
+  (if (not pred) body ...))
+
+(define-syntax-rule (when-not pred body ...)
+  (when (not pred) body ...))
+
 (define (partial fn . args)
   (lambda x (apply fn (append args x))))