Global generation

src/list.c

@@ -16,6 +16,14 @@ intptr_t list_length(LispVal *list) {
     return length;
 }
 
+bool list_length_eq(LispVal *list, intptr_t size) {
+    assert(LISTP(list));
+    while (size-- && CONSP(list)) {
+        list = XCDR(list);
+    }
+    return size == 0;
+}
+
 DEFUN(cons, "cons", (LispVal * car, LispVal *cdr), "(car cdr)",
       "Construct a new cons object from CAR and CDR.") {
     return CONS(car, cdr);
@@ -25,3 +33,21 @@ DEFUN(length, "length", (LispVal * list), "(list)", "") {
     // TODO type check
     return MAKE_FIXNUM(list_length(list));
 }
+
+DEFUN(length_eq, "length=", (LispVal * list, LispVal *length), "(list length)",
+      "Return non-nil if LIST's length is LENGTH.") {
+    // TODO type check
+    return list_length_eq(list, XFIXNUM(length)) ? Qt : Qnil;
+}
+
+DEFUN(nreverse, "nreverse", (LispVal * list), "(list)", "") {
+    // TODO type checking
+    LispVal *rev = Qnil;
+    while (!NILP(list)) {
+        LispVal *next = XCDR(list);
+        RPLACD(list, rev);
+        rev = list;
+        list = next;
+    }
+    return rev;
+}