Extend and test lists lib

Makefile

@@ -35,6 +35,7 @@ test: arcana-lisp
 	$(CAT) tests/arithm_ops.scm         | ./arcana-lisp $(LIBS)
 	$(CAT) tests/basic_data_structs.scm | ./arcana-lisp $(LIBS)
 	$(CAT) tests/equiv.scm              | ./arcana-lisp $(LIBS)
+	$(CAT) tests/lists.scm              | ./arcana-lisp $(LIBS)
 	$(CAT) tests/logic_ops.scm          | ./arcana-lisp $(LIBS)
 	$(CAT) tests/syntax.scm             | ./arcana-lisp $(LIBS)
 	$(CAT) tests/type_conv.scm          | ./arcana-lisp $(LIBS)

lib/lists.scm

@@ -1,3 +1,12 @@
+(define (first  x) (car   x))
+(define (second x) (cadr  x))
+(define (third  x) (caddr x))
+
+(define (last x)
+  (if (null? (cdr x))
+      (car x)
+      (last (cdr x))))
+
 (define (caar x) (car (car x)))
 (define (cadr x) (car (cdr x)))
 (define (cdar x) (cdr (car x)))

tests/lists.scm

@@ -0,0 +1,66 @@
+;;; first ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+(assert-equal 'a (first '(a)))
+(assert-equal 'a (first '(a b)))
+(assert-equal 'a (first '(a b c)))
+(assert-equal 'a (first '(a b c d)))
+
+;;; second ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+(assert-equal 'b (second '(a b)))
+(assert-equal 'b (second '(a b c)))
+(assert-equal 'b (second '(a b c d)))
+
+;;; third ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+(assert-equal 'c (third '(a b c)))
+(assert-equal 'c (third '(a b c d)))
+
+;;; last ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+(assert-equal 'a (last '(a)))
+(assert-equal 'b (last '(a b)))
+(assert-equal 'c (last '(a b c)))
+(assert-equal 'd (last '(a b c d)))
+
+;;; c(a|d){2}r ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+(let
+  ([lst
+     '((a b) c d)])
+  (begin
+    (assert-equal 'a   (caar lst))
+    (assert-equal '(b) (cdar lst))
+    (assert-equal 'c   (cadr lst))
+    (assert-equal '(d) (cddr lst))))
+
+;;; c(a|d){3}r ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+(let
+  ([lst
+     '(((a b) c d) (e f) g h)])
+  (begin
+    (assert-equal 'a   (caaar lst))
+    (assert-equal '(b) (cdaar lst))
+    (assert-equal 'c   (cadar lst))
+    (assert-equal '(d) (cddar lst))
+    (assert-equal 'e   (caadr lst))
+    (assert-equal '(f) (cdadr lst))
+    (assert-equal 'g   (caddr lst))
+    (assert-equal '(h) (cdddr lst))))
+
+;;; c(a|d){4}r ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+(let
+  ([lst
+     '((((a b) c d) (e f) g h) ((i j) k l) (m n) o p)])
+  (begin
+    (assert-equal 'a   (caaaar lst))
+    (assert-equal '(b) (cdaaar lst))
+    (assert-equal 'c   (cadaar lst))
+    (assert-equal '(d) (cddaar lst))
+    (assert-equal 'e   (caadar lst))
+    (assert-equal '(f) (cdadar lst))
+    (assert-equal 'g   (caddar lst))
+    (assert-equal '(h) (cdddar lst))
+    (assert-equal 'i   (caaadr lst))
+    (assert-equal '(j) (cdaadr lst))
+    (assert-equal 'k   (cadadr lst))
+    (assert-equal '(l) (cddadr lst))
+    (assert-equal 'm   (caaddr lst))
+    (assert-equal '(n) (cdaddr lst))
+    (assert-equal 'o   (cadddr lst))
+    (assert-equal '(p) (cddddr lst))))