allocator: implement a basic allocator

include/alisp/alisp.h

@@ -8,6 +8,7 @@
 #ifndef ALISP_H
 #define ALISP_H
 
+#include <alisp/allocator.h>
 #include <alisp/base.h>
 #include <alisp/lisp.h>
 #include <alisp/reader.h>

include/alisp/allocator.h

@@ -0,0 +1,57 @@
+/* allocator.h: Lisp Allocator
+ * Created: 2026-02-12
+ * Author: Aryadev Chavali
+ * License: See end of file
+ * Commentary:
+ */
+
+#ifndef ALLOCATOR_H
+#define ALLOCATOR_H
+
+#include <alisp/lisp.h>
+#include <alisp/vec.h>
+
+#define ALLOC_PAGE_DEFAULT_SIZE 512
+
+typedef struct
+{
+  u64 references;
+  tag_t tag : 8;
+} alloc_metadata_t;
+
+typedef struct
+{
+  alloc_metadata_t metadata;
+  u8 data[];
+} alloc_node_t;
+
+typedef struct
+{
+  vec_t data;
+} page_t;
+
+typedef struct
+{
+  vec_t pages;
+  vec_t free_list;
+} arena_t;
+
+lisp_t *arena_make(arena_t *, tag_t type);
+void arena_delete(arena_t *, lisp_t *);
+u64 arena_cost(arena_t *);
+void arena_free(arena_t *);
+
+#endif
+
+/* 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/>.
+
+ */