kernel: append + reverse + 11 tests [nothing]

Variadic append concatenates lists; reverse is unary. 307 tests total.

lib/kernel/runtime.sx

@@ -490,6 +490,48 @@
     "pair?"
     (fn (v) (and (list? v) (> (length v) 0)))))
 
+(define knl-append-step
+  (fn (xs ys)
+    (cond
+      ((or (nil? xs) (= (length xs) 0)) ys)
+      (:else (cons (first xs) (knl-append-step (rest xs) ys))))))
+
+(define knl-all-lists?
+  (fn (xs)
+    (cond
+      ((or (nil? xs) (= (length xs) 0)) true)
+      ((list? (first xs)) (knl-all-lists? (rest xs)))
+      (:else false))))
+
+(define knl-append-all
+  (fn (lists)
+    (cond
+      ((or (nil? lists) (= (length lists) 0)) (list))
+      ((= (length lists) 1) (first lists))
+      (:else
+        (knl-append-step (first lists)
+                         (knl-append-all (rest lists)))))))
+
+(define kernel-append-applicative
+  (kernel-make-primitive-applicative
+    (fn (args)
+      (cond
+        ((knl-all-lists? args) (knl-append-all args))
+        (:else (error "append: all arguments must be lists"))))))
+
+(define knl-reverse-step
+  (fn (xs acc)
+    (cond
+      ((or (nil? xs) (= (length xs) 0)) acc)
+      (:else (knl-reverse-step (rest xs) (cons (first xs) acc))))))
+
+(define kernel-reverse-applicative
+  (knl-unary-app "reverse"
+    (fn (xs)
+      (cond
+        ((not (list? xs)) (error "reverse: argument must be a list"))
+        (:else (knl-reverse-step xs (list)))))))
+
 (define kernel-not-applicative (knl-unary-app "not" (fn (v) (not v))))
 
 (define kernel-eq?-applicative (knl-bin-app "eq?" (fn (a b) (= a b))))
@@ -816,7 +858,9 @@
       (kernel-env-bind! env "map"    kernel-map-applicative)
       (kernel-env-bind! env "filter" kernel-filter-applicative)
       (kernel-env-bind! env "reduce" kernel-reduce-applicative)
-      (kernel-env-bind! env "apply"  kernel-apply-applicative)
+      (kernel-env-bind! env "apply"   kernel-apply-applicative)
+      (kernel-env-bind! env "append"  kernel-append-applicative)
+      (kernel-env-bind! env "reverse" kernel-reverse-applicative)
       (kernel-env-bind! env "not" kernel-not-applicative)
       (kernel-env-bind! env "make-encapsulation-type"
                             kernel-make-encap-type-applicative)