lisp: split lisp into lisp and sys

Generic definition of tagged pointers, along with simple
constructor/destructors should be in lisp.h for use by other headers.

sys.h on the other hand contains all the general system methods.

src/sys.c

@@ -0,0 +1,195 @@
+/* sys.c: System implementation
+ * Created: 2026-02-12
+ * Author: Aryadev Chavali
+ * License: See end of file
+ * Commentary:
+ */
+
+#include <stdlib.h>
+#include <string.h>
+
+#include <alisp/sys.h>
+
+void sys_init(sys_t *sys)
+{
+  memset(sys, 0, sizeof(*sys));
+}
+
+lisp_t *sys_alloc(sys_t *sys, tag_t type)
+{
+  switch (type)
+  {
+  case TAG_CONS:
+  {
+    cons_t *cons = calloc(1, sizeof(*cons));
+    lisp_t *lisp = tag_cons(cons);
+    vec_append(&sys->memory.conses, &lisp, sizeof(&lisp));
+    sys->memory.num_conses++;
+    return lisp;
+  }
+  case TAG_VEC:
+  {
+    vec_t *vec   = calloc(1, sizeof(*vec));
+    lisp_t *lisp = tag_vec(vec);
+    vec_append(&sys->memory.vectors, &lisp, sizeof(&lisp));
+    sys->memory.num_vectors++;
+    return lisp;
+  }
+  // Shouldn't be registered
+  case TAG_NIL:
+  case TAG_INT:
+  case TAG_SYM:
+  default:
+    FAIL("Unreachable");
+  }
+  return NIL;
+}
+
+u64 sys_cost(sys_t *sys)
+{
+  u64 vec_capacity = 0;
+  for (u64 i = 0; i < sys->memory.num_vectors; ++i)
+  {
+    lisp_t *vec = VEC_GET(&sys->memory.vectors, i, lisp_t *);
+    vec_capacity += as_vec(vec)->capacity;
+  }
+  return sym_table_cost(&sys->symtable) +
+         (sys->memory.num_conses * sizeof(cons_t)) + vec_capacity;
+}
+
+void sys_free(sys_t *sys)
+{
+  sym_table_free(&sys->symtable);
+
+  // Iterate through each cell of memory currently allocated and free them
+  for (size_t i = 0; i < VEC_SIZE(&sys->memory.conses, lisp_t **); ++i)
+  {
+    lisp_t *allocated = VEC_GET(&sys->memory.conses, i, lisp_t *);
+    lisp_free(allocated);
+  }
+
+  // Iterate through each cell of memory currently allocated and free them
+  for (size_t i = 0; i < VEC_SIZE(&sys->memory.vectors, lisp_t **); ++i)
+  {
+    lisp_t *allocated = VEC_GET(&sys->memory.vectors, i, lisp_t *);
+    lisp_free(allocated);
+  }
+
+  // Free the containers
+  vec_free(&sys->memory.conses);
+  vec_free(&sys->memory.vectors);
+
+  // Ensure no one treats this as active in any sense
+  memset(sys, 0, sizeof(*sys));
+}
+
+lisp_t *make_int(i64 i)
+{
+  return tag_int(i);
+}
+
+lisp_t *cons(sys_t *sys, lisp_t *car, lisp_t *cdr)
+{
+  lisp_t *cons = sys_alloc(sys, TAG_CONS);
+  CAR(cons)    = car;
+  CDR(cons)    = cdr;
+  return cons;
+}
+
+lisp_t *make_vec(sys_t *sys, u64 capacity)
+{
+  lisp_t *vec = sys_alloc(sys, TAG_VEC);
+  vec_init(as_vec(vec), capacity);
+  return vec;
+}
+
+lisp_t *intern(sys_t *sys, sv_t sv)
+{
+  const char *str = sym_table_find(&sys->symtable, sv);
+  return tag_sym(str);
+}
+
+lisp_t *car(lisp_t *lsp)
+{
+  if (!IS_TAG(lsp, CONS))
+    return NIL;
+  else
+    return CAR(lsp);
+}
+
+lisp_t *cdr(lisp_t *lsp)
+{
+  if (!IS_TAG(lsp, CONS))
+    return NIL;
+  else
+    return CDR(lsp);
+}
+
+void lisp_free(lisp_t *item)
+{
+  switch (get_tag(item))
+  {
+  case TAG_CONS:
+    // Delete the cons
+    free(as_cons(item));
+    break;
+  case TAG_VEC:
+  {
+    vec_t *vec = as_vec(item);
+    vec_free(vec);
+    free(vec);
+    break;
+  }
+  case TAG_NIL:
+  case TAG_INT:
+  case TAG_SYM:
+  case NUM_TAGS:
+    // shouldn't be dealt with (either constant or dealt with elsewhere)
+    break;
+  }
+}
+
+void lisp_free_rec(lisp_t *item)
+{
+  switch (get_tag(item))
+  {
+  case TAG_CONS:
+  {
+    lisp_free_rec(car(item));
+    lisp_free_rec(cdr(item));
+    free(as_cons(item));
+    break;
+  }
+  case TAG_VEC:
+  {
+    vec_t *vec = as_vec(item);
+    for (size_t i = 0; i < VEC_SIZE(vec, lisp_t **); ++i)
+    {
+      lisp_t *allocated = VEC_GET(vec, i, lisp_t *);
+      lisp_free_rec(allocated);
+    }
+    vec_free(vec);
+    free(vec);
+    break;
+  }
+  case TAG_NIL:
+  case TAG_INT:
+  case TAG_SYM:
+  case NUM_TAGS:
+    // shouldn't be dealt with (either constant or dealt with elsewhere)
+    break;
+  }
+}
+
+/* Copyright (C) 2026 Aryadev Chavali
+
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+ * FOR A PARTICULAR PURPOSE.  See the GNU General Public License Version 2 for
+ * details.
+
+ * You may distribute and modify this code under the terms of the GNU General
+ * Public License Version 2, which you should have received a copy of along with
+ * this program.  If not, please go to <https://www.gnu.org/licenses/>.
+
+ */