Make conses a vector, add VEC_SIZE macro

Easier to iterate through, O(1) amortized registering just like the
Linked List.

VEC_SIZE just makes it easier to iterate through a vector of specially
typed elements.

alisp.h

@@ -76,7 +76,8 @@ typedef struct Vector
 
 static_assert(sizeof(vec_t) == 64, "vec_t has to be 64 bytes as part of SBO");
 
-#define VEC_GET(V, T) ((T *)vec_data(V))
+#define VEC_GET(V, T)  ((T *)vec_data(V))
+#define VEC_SIZE(V, T) ((V)->size / (sizeof(T)))
 
 void vec_init(vec_t *, u64);
 void vec_free(vec_t *);
@@ -183,7 +184,7 @@ typedef struct
 /// System context
 typedef struct
 {
-  lisp_t *conses;
+  vec_t conses;
   sym_table_t symtable;
 } sys_t;
 

runtime/sys.c

@@ -25,11 +25,8 @@ void sys_init(sys_t *sys)
 
 void sys_register(sys_t *sys, lisp_t *ptr)
 {
-  // Generate an unmanaged cons
-  cons_t *cons = calloc(1, sizeof(*cons));
-  cons->car    = ptr;
-  cons->cdr    = sys->conses;
-  sys->conses  = tag_cons(cons);
+  // Simply append it to the list of currently active conses
+  vec_append(&sys->conses, ptr, sizeof(ptr));
 }
 
 void sys_cleanup(sys_t *sys)
@@ -37,18 +34,13 @@ void sys_cleanup(sys_t *sys)
   static_assert(NUM_TAGS == 5);
 
   sym_table_cleanup(&sys->symtable);
-
-  if (!sys->conses)
+  if (sys->conses.size == 0)
     return;
 
-  // Iterate through each element of memory
-  for (lisp_t *cell = sys->conses, *next = cdr(cell); cell;
-       cell = next, next = cdr(next))
+  // Iterate through each cons currently allocated and free them
+  for (size_t i = 0; i < VEC_SIZE(&sys->conses, lisp_t **); ++i)
   {
-    // Only reason allocated exists is because we had to allocate memory on the
-    // heap for it.  It's therefore enough to deal with only the allocated
-    // types.
-    lisp_t *allocated = car(cell);
+    lisp_t *allocated = VEC_GET(&sys->conses, lisp_t *)[i];
     switch (get_tag(allocated))
     {
     case TAG_CONS:
@@ -69,9 +61,11 @@ void sys_cleanup(sys_t *sys)
       // shouldn't be dealt with (either constant or dealt with elsewhere)
       break;
     }
-
-    // Then free the current cell
-    free(as_cons(cell));
   }
+
+  // Free the container
+  vec_free(&sys->conses);
+
+  // Ensure no one treats this as active in any sense
   memset(sys, 0, sizeof(*sys));
 }