allocator: rework alloc_delete

Added a switch case at start of alloc_delete to only run it on
container (read: heap allocated) types.

If adding to free vector, iterate through free vector first to ensure
we've not added it already.  Reset the object before adding it, so
reuse is trivial.

Makefile

@@ -5,21 +5,22 @@ OUT=$(DIST)/alisp.out
 TEST=$(DIST)/test.out
 
 LDFLAGS=
-GFLAGS=-Wall -Wextra -Wpedantic -Werror -std=c23 -I./include/
-DFLAGS=-ggdb -fsanitize=address -fsanitize=undefined -DVERBOSE_LOGS=1
+GFLAGS=-Wall -Wextra -Wswitch-enum -Wpedantic -Werror -std=c23 -I./include/
+DFLAGS=-ggdb -fsanitize=address -fsanitize=undefined
 RFLAGS=-O3
 
 MODE=release
 ifeq ($(MODE), release)
 CFLAGS=$(GFLAGS) $(RFLAGS)
 else ifeq ($(MODE), debug)
-CFLAGS=$(GFLAGS) $(DFLAGS)
+CFLAGS=$(GFLAGS) $(DFLAGS) -DVERBOSE_LOGS=1
 else ifeq ($(MODE), full)
-CFLAGS=$(GFLAGS) $(DFLAGS) -DTEST_VERBOSE=1
+CFLAGS=$(GFLAGS) $(DFLAGS) -DVERBOSE_LOGS=2 -DTEST_VERBOSE=1
 endif
 
 # Units to compile
-UNITS=src/sv.c src/vec.c src/stream.c src/symtable.c src/tag.c src/lisp.c src/reader.c
+UNITS=src/sv.c src/vec.c src/string.c src/stream.c src/symtable.c src/lisp.c \
+		src/allocator.c src/sys.c src/reader.c
 OBJECTS:=$(patsubst src/%.c, $(DIST)/%.o, $(UNITS))
 
 TEST_UNITS=test/main.c

alisp.org

@@ -84,7 +84,7 @@ Scheme doesn't have it.  Should we implement this?
 - Unmanaged objects are allocations we do as part of the runtime.
   These are things that we expect to have near infinite lifetimes
   (such as the symbol table, vector of allocated objects, etc).
-*** TODO Design an allocator
+*** DONE Design an allocator
 We'll need an allocator for all our managed objects.  Requirements:
 - Stable pointers (memory that has already been allocated should be
   free to utilise via the same pointer for the lifetime of the
@@ -92,14 +92,15 @@ We'll need an allocator for all our managed objects.  Requirements:
 - Able to tag allocations as unused (i.e. "free") and able to reuse
   these allocations
   - This will link into the garbage collector, which should yield a
-    sequence of objects that should be "freed".
+    sequence of objects that were previously tagged as unfree and
+    should be "freed".
 - Able to allocate all the managed types we have
-**** TODO Design allocation data structures
-**** TODO Design allocation methods for different lisp types
-- Conses
-- Vectors
+**** DONE Design allocation data structures
+**** DONE Design allocation methods for different lisp types
 - Strings (when implemented)
-**** TODO Design allocation freeing methods
+***** DONE Conses
+***** DONE Vectors
+**** DONE Design allocation freeing method
 *** TODO Design garbage collection scheme :gc:
 Really, regardless of what I do, we need to have some kind of garbage
 collection header on whatever managed objects we allocate.  We need to

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 +1,61 @@
+/* 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 padding : 56;
+  tag_t tag   : 8;
+  u64 references;
+} alloc_metadata_t;
+
+static_assert(sizeof(alloc_metadata_t) == 16,
+              "16 byte metadata required for alignment purposes");
+
+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_vec;
+} alloc_t;
+
+lisp_t *alloc_make(alloc_t *, tag_t type);
+void alloc_delete(alloc_t *, lisp_t *);
+u64 alloc_cost(alloc_t *);
+void alloc_free(alloc_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/>.
+
+ */

include/alisp/lisp.h

@@ -10,7 +10,7 @@
 
 #include <stdio.h>
 
-#include <alisp/symtable.h>
+#include <alisp/string.h>
 #include <alisp/vec.h>
 
 #define NIL 0
@@ -26,89 +26,50 @@ typedef struct
 /// Tagging system
 typedef enum Tag
 {
-  TAG_NIL  = 0b00000000, // Start of atomic types
-  TAG_INT  = 0b00000001, // Special tag so we can encode 63 bit integers
-  TAG_SYM  = 0b00000100,
-  TAG_CONS = 0b00000010, // Start of container types
-  TAG_VEC  = 0b00000110,
-  NUM_TAGS = 5,
+  TAG_SMI  = 0b00000001, // Atomic types
+  TAG_SYM  = 0b00000011,
+  TAG_NIL  = 0b00000000, // Container types (0 LSB)
+  TAG_CONS = 0b00000010,
+  TAG_VEC  = 0b00000100,
+  TAG_STR  = 0b00000110,
+  NUM_TAGS = 6,
 } tag_t;
 
-static_assert(NUM_TAGS == 5, "Expected NUM_TAGS == 5 for enum SHIFT");
-enum Shift
-{
-  SHIFT_INT  = 1,
-  SHIFT_SYM  = 8,
-  SHIFT_CONS = 8,
-  SHIFT_VEC  = 8,
-};
-
-static_assert(NUM_TAGS == 5, "Expected NUM_TAGS == 5 for enum MASK");
-enum Mask
-{
-  MASK_INT  = 0b00000001,
-  MASK_SYM  = 0b11111111,
-  MASK_CONS = 0b11111111,
-  MASK_VEC  = 0b11111111,
-};
-
 // Some helper macros for tagging
-#define TAG(PTR, TYPE)    ((lisp_t *)(((PTR) << SHIFT_##TYPE) | TAG_##TYPE))
-#define IS_TAG(PTR, TYPE) (((u64)(PTR) & MASK_##TYPE) == TAG_##TYPE)
-#define UNTAG(PTR, TYPE)  (((u64)PTR) >> SHIFT_##TYPE)
+#define SHIFT_TAG (8)
+#define MASK_TAG  ((1 << SHIFT_TAG) - 1)
 
-#define INT_MAX ((((i64)1) << 62) - 1)
-#define INT_MIN (-(((i64)1) << 62))
+#define TAG(PTR, TYPE)    ((lisp_t *)((((u64)(PTR)) << SHIFT_TAG) | TAG_##TYPE))
+#define UNTAG(PTR)        (((u64)PTR) >> SHIFT_TAG)
+#define GET_TAG(PTR)      ((tag_t)(((u64)(PTR)) & MASK_TAG))
+#define IS_TAG(PTR, TYPE) (GET_TAG(PTR) == TAG_##TYPE)
 
-tag_t get_tag(const lisp_t *);
-lisp_t *tag_int(const i64);
+#define INT_BITS ((sizeof(i64) * 8) - SHIFT_TAG)
+#define INT_MAX  ((((i64)1) << (INT_BITS - 1)) - 1)
+#define INT_MIN  (-(INT_MAX + 1))
+
+tag_t tag_get(const lisp_t *);
+u64 tag_sizeof(tag_t);
+u64 lisp_sizeof(lisp_t *);
+lisp_t *lisp_reset(lisp_t *);
+void lisp_print(FILE *, lisp_t *);
+
+lisp_t *tag_smi(const i64);
 lisp_t *tag_sym(const char *);
 lisp_t *tag_cons(const cons_t *);
 lisp_t *tag_vec(const vec_t *);
+lisp_t *tag_str(const str_t *);
+lisp_t *tag_generic(void *, tag_t);
 
-/// System context
-typedef struct
-{
-  vec_t conses;
-  vec_t vectors;
-  u64 num_conses, num_vectors;
-} sys_mem_t;
-
-typedef struct
-{
-  sys_mem_t memory;
-  sym_table_t symtable;
-} sys_t;
-
-void sys_init(sys_t *);
-lisp_t *sys_alloc(sys_t *, tag_t type);
-void sys_free(sys_t *);
-
-// Debugging function: provides total memory usage from system.
-u64 sys_cost(sys_t *);
-
-/// Constructors and destructors
-lisp_t *make_int(i64);
-lisp_t *make_vec(sys_t *, u64);
-lisp_t *intern(sys_t *, sv_t);
-lisp_t *cons(sys_t *, lisp_t *, lisp_t *);
-
-i64 as_int(lisp_t *);
+i64 as_smi(lisp_t *);
 char *as_sym(lisp_t *);
 cons_t *as_cons(lisp_t *);
 vec_t *as_vec(lisp_t *);
+str_t *as_str(lisp_t *);
 
 #define CAR(L) (as_cons(L)->car)
 #define CDR(L) (as_cons(L)->cdr)
 
-lisp_t *car(lisp_t *);
-lisp_t *cdr(lisp_t *);
-
-void lisp_free(lisp_t *);
-void lisp_free_rec(lisp_t *);
-
-void lisp_print(FILE *, lisp_t *);
-
 #endif
 
 /* Copyright (C) 2026 Aryadev Chavali

include/alisp/reader.h

@@ -8,8 +8,8 @@
 #ifndef READER_H
 #define READER_H
 
-#include <alisp/lisp.h>
 #include <alisp/stream.h>
+#include <alisp/sys.h>
 
 typedef enum
 {
@@ -17,6 +17,7 @@ typedef enum
   READ_ERR_EOF,
   READ_ERR_EXPECTED_CLOSED_BRACE,
   READ_ERR_EXPECTED_CLOSED_SQUARE_BRACKET,
+  READ_ERR_EXPECTED_CLOSING_SPEECHMARKS,
   READ_ERR_UNEXPECTED_CLOSED_BRACE,
   READ_ERR_UNEXPECTED_CLOSED_SQUARE_BRACKET,
   READ_ERR_UNKNOWN_CHAR,

include/alisp/string.h

@@ -0,0 +1,35 @@
+/* string.h: String library
+ * Created: 2026-03-05
+ * Author: Aryadev Chavali
+ * License: See end of file
+ * Commentary:
+ */
+
+#ifndef STRING_H
+#define STRING_H
+
+#include <alisp/sv.h>
+#include <alisp/vec.h>
+
+typedef struct
+{
+  vec_t data;
+} str_t;
+
+str_t string_make(sv_t sv);
+sv_t string_sv(str_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/>.
+
+ */

include/alisp/sys.h

@@ -0,0 +1,57 @@
+/* sys.h: System context and constructors
+ * Created: 2026-02-12
+ * Author: Aryadev Chavali
+ * License: See end of file
+ * Commentary:
+ */
+
+#ifndef SYS_H
+#define SYS_H
+
+#include <alisp/allocator.h>
+#include <alisp/lisp.h>
+#include <alisp/symtable.h>
+
+/// System context
+typedef struct
+{
+  alloc_t memory;
+  sym_table_t symtable;
+} sys_t;
+
+void sys_init(sys_t *);
+lisp_t *sys_alloc(sys_t *, tag_t type);
+void sys_delete(sys_t *, lisp_t *);
+void sys_free(sys_t *);
+
+// Debugging function: provides total memory usage from system.
+u64 sys_cost(sys_t *);
+
+/// Constructors and general Lisp API
+lisp_t *make_int(i64);
+lisp_t *intern(sys_t *, sv_t);
+lisp_t *cons(sys_t *, lisp_t *, lisp_t *);
+lisp_t *make_list(sys_t *, lisp_t **, u64);
+lisp_t *make_vec(sys_t *, u64);
+lisp_t *make_str(sys_t *, u64);
+
+lisp_t *car(lisp_t *);
+lisp_t *cdr(lisp_t *);
+
+void lisp_free(sys_t *, lisp_t *);
+void lisp_free_rec(sys_t *, lisp_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/>.
+
+ */

include/alisp/vec.h

@@ -31,12 +31,18 @@ static_assert(sizeof(vec_t) == 64, "vec_t has to be 64 bytes as part of SBO");
 
 #define VEC_GET(V, I, T) (((T *)vec_data(V))[I])
 #define VEC_SIZE(V, T)   ((V)->size / (sizeof(T)))
+#define FOR_VEC(INDEX, V, T) \
+  for (size_t INDEX = 0; INDEX < VEC_SIZE(V, T); ++INDEX)
 
 void vec_init(vec_t *, u64);
 void vec_free(vec_t *);
+void vec_reset(vec_t *);
 u8 *vec_data(vec_t *);
 
+// Append, possibly reallocating memory
 void vec_append(vec_t *, const void *const, u64);
+// Try to append without allocating memory
+bool vec_try_append(vec_t *, const void *const, u64);
 void vec_ensure_free(vec_t *, u64);
 void vec_clone(vec_t *, vec_t *);
 

src/allocator.c

@@ -0,0 +1,256 @@
+/* allocator.c: Allocator implementations
+ * Created: 2026-02-12
+ * Author: Aryadev Chavali
+ * License: See end of file
+ * Commentary:
+ */
+
+#include <stdlib.h>
+
+#include <alisp/allocator.h>
+#include <alisp/lisp.h>
+#include <alisp/vec.h>
+#include <string.h>
+
+page_t *make_page(u64 size)
+{
+  page_t *page = calloc(1, sizeof(*page));
+  vec_init(&page->data, MAX(size, ALLOC_PAGE_DEFAULT_SIZE));
+  return page;
+}
+
+alloc_node_t *make_node(page_t *page, tag_t type)
+{
+  alloc_node_t *node = NULL;
+  u64 size           = sizeof(*node);
+
+  static_assert(NUM_TAGS == 6);
+  switch (type)
+  {
+  case TAG_CONS:
+    size += sizeof(cons_t);
+    break;
+  case TAG_VEC:
+    size += sizeof(vec_t);
+    break;
+  case TAG_STR:
+    size += sizeof(str_t);
+    break;
+  case TAG_NIL:
+  case TAG_SMI:
+  case TAG_SYM:
+  default:
+    FAIL("Unreachable");
+    return node;
+  }
+
+  // We must ensure size is a multiple of 8 for alignment purposes
+  size = (size & 0b111) == 0 ? size : size + (8 - (size & 0b111));
+
+  if (!vec_try_append(&page->data, NULL, size))
+    return NULL;
+  node = (alloc_node_t *)(vec_data(&page->data) + page->data.size - size);
+  node->metadata = (alloc_metadata_t){.references = 0, .tag = type};
+  return node;
+}
+
+alloc_node_t *lisp_to_node(lisp_t *lisp)
+{
+  void *raw_ptr = NULL;
+
+  static_assert(NUM_TAGS == 6);
+  switch (tag_get(lisp))
+  {
+  case TAG_CONS:
+    raw_ptr = as_cons(lisp);
+    break;
+  case TAG_VEC:
+    raw_ptr = as_vec(lisp);
+    break;
+  case TAG_STR:
+    raw_ptr = as_str(lisp);
+    break;
+  case TAG_NIL: // These shouldn't be allocated
+  case TAG_SMI:
+  case TAG_SYM:
+  default:
+    FAIL("Unreachable");
+    return NIL;
+  }
+
+  alloc_node_t *node = raw_ptr;
+  return &node[-1];
+}
+
+lisp_t *alloc_make(alloc_t *alloc, tag_t type)
+{
+  static_assert(NUM_TAGS == 6);
+  switch (type)
+  {
+  case TAG_CONS:
+  case TAG_VEC:
+  case TAG_STR:
+    break;
+  case TAG_NIL: // These shouldn't be allocated
+  case TAG_SMI:
+  case TAG_SYM:
+  default:
+    FAIL("Unreachable");
+    return NIL;
+  }
+
+  // We want to try to fill this node with an allocation of this type.
+  alloc_node_t *node = NULL;
+
+  // Try to get something from the free vector
+  u64 free_vec_size = VEC_SIZE(&alloc->free_vec, alloc_node_t *);
+  for (u64 i = 0; i < free_vec_size; ++i)
+  {
+    alloc_node_t **nodeptr = &VEC_GET(&alloc->free_vec, i, alloc_node_t *);
+
+    // Skip any nodes that don't have the right type.
+    if (nodeptr[0]->metadata.tag != type)
+      continue;
+
+    assert("Expected free node to have no references" &&
+           nodeptr[0]->metadata.references == 0);
+
+    // Pop this node off the free vector by swapping it with the last item and
+    // decrementing the size of the vector.
+
+    alloc_node_t **lastptr =
+        &VEC_GET(&alloc->free_vec, free_vec_size - 1, alloc_node_t *);
+    alloc_node_t *val = *nodeptr;
+    *nodeptr          = *lastptr;
+    *lastptr          = val;
+
+    // Decrement the size of the free vector
+    alloc->free_vec.size -= sizeof(val);
+
+    // Then use that valid (and now unused) node as our return.
+    node = *lastptr;
+
+    goto end;
+  }
+
+  // We couldn't get anything from the free vector, so try to allocate a fresh
+  // one against one of the pages.
+  FOR_VEC(i, &alloc->pages, page_t *)
+  {
+    page_t *page = VEC_GET(&alloc->pages, i, page_t *);
+    node         = make_node(page, type);
+    if (node)
+      goto end;
+  }
+
+  // There aren't any pages we can allocate against, so we need to make a new
+  // page.
+  page_t *page = make_page(0);
+  vec_append(&alloc->pages, &page, sizeof(page));
+  node = make_node(page, type);
+
+end:
+  if (!node)
+    FAIL("Unexpected issue with allocating to a verifiably good page");
+
+  return tag_generic(node->data, type);
+}
+
+void alloc_delete(alloc_t *alloc, lisp_t *lisp)
+{
+  switch (tag_get(lisp))
+  {
+  case TAG_CONS:
+  case TAG_VEC:
+  case TAG_STR:
+    break;
+  case TAG_NIL: // These can't be deleted (not allocated)
+  case TAG_SMI:
+  case TAG_SYM:
+  default:
+    FAIL("Unreachable");
+    return;
+  }
+
+  alloc_node_t *node = lisp_to_node(lisp);
+  assert(node && node->metadata.references == 0);
+
+  // If already present in the free vector, stop.
+  FOR_VEC(i, &alloc->free_vec, alloc_node_t *)
+  {
+    alloc_node_t *other = VEC_GET(&alloc->pages, i, alloc_node_t *);
+    if (other == node)
+    {
+      return;
+    }
+  }
+
+  // Otherwise, add to the free vector.
+  lisp_reset(lisp);
+  vec_append(&alloc->free_vec, &node, sizeof(node));
+}
+
+u64 alloc_cost(alloc_t *alloc)
+{
+  u64 total_size = alloc->pages.size;
+  FOR_VEC(i, &alloc->pages, page_t *)
+  {
+    page_t *page = VEC_GET(&alloc->pages, i, page_t *);
+    total_size += page->data.size;
+  }
+  return total_size;
+}
+
+void alloc_free(alloc_t *alloc)
+{
+  FOR_VEC(i, &alloc->pages, page_t *)
+  {
+    page_t *page = VEC_GET(&alloc->pages, i, page_t *);
+    // Iterate through every alloc_node in this page (dynamic walk)
+    for (u64 j = 0; j < VEC_SIZE(&page->data, u8);)
+    {
+      alloc_node_t *node = (alloc_node_t *)(vec_data(&page->data) + j);
+      u64 next           = sizeof(*node) + tag_sizeof(node->metadata.tag);
+
+      static_assert(NUM_TAGS == 6);
+      switch (node->metadata.tag)
+      {
+      case TAG_CONS:
+        // Do nothing - will be cleaned by overall vec free anyway
+        break;
+      case TAG_VEC:
+        vec_free((vec_t *)node->data);
+        break;
+      case TAG_STR:
+        vec_free(&((str_t *)node->data)->data);
+        break;
+      case TAG_NIL:
+      case TAG_SMI:
+      case TAG_SYM:
+      default:
+        FAIL("Unreachable");
+      }
+      j += next;
+    }
+
+    // Each page was allocated on the heap.
+    vec_free(&page->data);
+    free(page);
+  }
+  vec_free(&alloc->pages);
+  vec_free(&alloc->free_vec);
+  memset(alloc, 0, sizeof(*alloc));
+}
+
+/* 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/>.
+
+ */

src/lisp.c

@@ -10,207 +10,123 @@
 
 #include <alisp/lisp.h>
 
-void sys_init(sys_t *sys)
+lisp_t *tag_smi(i64 i)
 {
-  memset(sys, 0, sizeof(*sys));
+  return TAG(i, SMI);
 }
 
-lisp_t *sys_alloc(sys_t *sys, tag_t type)
+lisp_t *tag_sym(const char *str)
 {
+  return TAG(str, SYM);
+}
+
+lisp_t *tag_vec(const vec_t *vec)
+{
+  return TAG(vec, VEC);
+}
+
+lisp_t *tag_str(const str_t *str)
+{
+  return TAG(str, STR);
+}
+
+lisp_t *tag_cons(const cons_t *cons)
+{
+  return TAG(cons, CONS);
+}
+
+lisp_t *tag_generic(void *ptr, tag_t type)
+{
+  static_assert(NUM_TAGS == 6);
   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:
+    return TAG(ptr, NIL);
+  case TAG_SMI:
+    return tag_smi((i64)ptr);
   case TAG_SYM:
+    return tag_sym(ptr);
+  case TAG_CONS:
+    return tag_cons(ptr);
+  case TAG_VEC:
+    return tag_vec(ptr);
+  case TAG_STR:
+    return tag_str(ptr);
   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)
+tag_t tag_get(const lisp_t *lisp)
 {
-  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);
+  return GET_TAG(lisp);
 }
 
-  // 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)
+i64 as_smi(lisp_t *obj)
 {
-    lisp_t *allocated = VEC_GET(&sys->memory.vectors, i, lisp_t *);
-    lisp_free(allocated);
+  assert(IS_TAG(obj, SMI));
+  u64 raw_obj = UNTAG(obj);
+  u64 msb     = (NTH_BYTE(raw_obj, 6) & 0x80) >> 7;
+  msb         = ((1LU << 8) - msb) << 56;
+  return (i64)(raw_obj | msb);
 }
 
-  // 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));
+char *as_sym(lisp_t *obj)
+{
+  assert(IS_TAG(obj, SYM));
+  return (char *)UNTAG(obj);
 }
 
-lisp_t *make_int(i64 i)
+cons_t *as_cons(lisp_t *obj)
 {
-  return tag_int(i);
+  assert(IS_TAG(obj, CONS));
+  return (cons_t *)UNTAG(obj);
 }
 
-lisp_t *cons(sys_t *sys, lisp_t *car, lisp_t *cdr)
+str_t *as_str(lisp_t *obj)
 {
-  lisp_t *cons = sys_alloc(sys, TAG_CONS);
-  CAR(cons)    = car;
-  CDR(cons)    = cdr;
-  return cons;
+  assert(IS_TAG(obj, STR));
+  return (str_t *)UNTAG(obj);
 }
 
-lisp_t *make_vec(sys_t *sys, u64 capacity)
+vec_t *as_vec(lisp_t *obj)
 {
-  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;
-  }
+  assert(IS_TAG(obj, VEC));
+  return (vec_t *)UNTAG(obj);
 }
 
 void lisp_print(FILE *fp, lisp_t *lisp)
 {
   if (!fp)
     return;
-  switch (get_tag(lisp))
+  static_assert(NUM_TAGS == 6);
+  switch (tag_get(lisp))
   {
   case TAG_NIL:
     fprintf(fp, "NIL");
     break;
-  case TAG_INT:
-#if VERBOSE_LOGS
+  case TAG_SMI:
+#if VERBOSE_LOGS == 2
     fprintf(fp, "INT[");
 #endif
-    fprintf(fp, "%ld", as_int(lisp));
-#if VERBOSE_LOGS
+    fprintf(fp, "%ld", as_smi(lisp));
+#if VERBOSE_LOGS == 2
     fprintf(fp, "]");
 #endif
     break;
   case TAG_SYM:
-#if VERBOSE_LOGS
+#if VERBOSE_LOGS == 2
     fprintf(fp, "SYM[");
 #endif
     fprintf(fp, "%s", as_sym(lisp));
-#if VERBOSE_LOGS
+#if VERBOSE_LOGS == 2
     fprintf(fp, "]");
 #endif
     break;
   case TAG_CONS:
   {
-#if VERBOSE_LOGS
+#if VERBOSE_LOGS == 2
     fprintf(fp, "LIST[");
 #else
     fprintf(fp, "(");
@@ -238,7 +154,7 @@ void lisp_print(FILE *fp, lisp_t *lisp)
         break;
       }
     }
-#if VERBOSE_LOGS
+#if VERBOSE_LOGS == 2
     fprintf(fp, "]");
 #else
     fprintf(fp, ")");
@@ -247,37 +163,115 @@ void lisp_print(FILE *fp, lisp_t *lisp)
   }
   case TAG_VEC:
   {
-#if VERBOSE_LOGS
+#if VERBOSE_LOGS == 2
     fprintf(fp, "VEC[");
 #else
     fprintf(fp, "[");
 #endif
 
     vec_t *vec = as_vec(lisp);
-    for (u64 i = 1; i <= VEC_SIZE(vec, lisp_t *); ++i)
+    FOR_VEC(i, vec, lisp_t *)
     {
-      lisp_t *item = VEC_GET(vec, i - 1, lisp_t *);
+      lisp_t *item = VEC_GET(vec, i, lisp_t *);
       lisp_print(fp, item);
-      if (i != VEC_SIZE(vec, lisp_t *))
+      if (i < VEC_SIZE(vec, lisp_t *) - 1)
       {
         fprintf(fp, " ");
       }
     }
 
-#if VERBOSE_LOGS
+#if VERBOSE_LOGS == 2
     fprintf(fp, "]");
 #else
     fprintf(fp, "]");
 #endif
     break;
   }
-  case NUM_TAGS:
+  case TAG_STR:
+  {
+#if VERBOSE_LOGS == 2
+    fprintf(fp, "STR[");
+#else
+    fprintf(fp, "\"");
+#endif
+
+    sv_t sv = string_sv(as_str(lisp));
+    fprintf(fp, PR_SV, SV_FMT(sv));
+
+#if VERBOSE_LOGS == 2
+    fprintf(fp, "]");
+#else
+    fprintf(fp, "\"");
+#endif
+    break;
+  }
   default:
     FAIL("Unreachable");
     break;
   }
 }
 
+u64 tag_sizeof(tag_t tag)
+{
+  static_assert(NUM_TAGS == 6);
+  switch (tag)
+  {
+  case TAG_NIL:
+    return 0;
+  case TAG_SMI:
+  case TAG_SYM:
+    return sizeof(lisp_t *);
+  case TAG_CONS:
+    return sizeof(cons_t);
+  case TAG_VEC:
+    return sizeof(vec_t);
+  case TAG_STR:
+    return sizeof(str_t);
+  default:
+    FAIL("Unreachable");
+    return 0;
+  }
+}
+
+u64 lisp_sizeof(lisp_t *lisp)
+{
+  return tag_sizeof(tag_get(lisp));
+}
+
+lisp_t *lisp_reset(lisp_t *lisp)
+{
+  switch (tag_get(lisp))
+  {
+  case TAG_NIL:
+  case TAG_SMI:
+  case TAG_SYM:
+    // Nothing to "reset" here.
+    return lisp;
+  case TAG_CONS:
+  {
+    // Make `car` and `cons` NIL
+    CAR(lisp) = NIL;
+    CDR(lisp) = NIL;
+    return lisp;
+  }
+  case TAG_VEC:
+  {
+    vec_reset(as_vec(lisp));
+    return lisp;
+  }
+  case TAG_STR:
+  {
+    vec_reset(&as_str(lisp)->data);
+    return lisp;
+  }
+  default:
+  {
+    FAIL("Unreachable");
+    return lisp;
+  }
+  }
+}
+
 /* Copyright (C) 2025, 2026 Aryadev Chavali
 
  * This program is distributed in the hope that it will be useful, but WITHOUT

src/main.c

@@ -45,10 +45,10 @@ int main(int argc, char *argv[])
       VEC_SIZE(&ast, lisp_t *) == 1 ? "expr" : "exprs");
 
   {
-    for (u64 i = 0; i < VEC_SIZE(&ast, lisp_t *); ++i)
+    FOR_VEC(i, &ast, lisp_t *)
     {
-      lisp_t *expr = VEC_GET(&ast, i, lisp_t *);
 #if VERBOSE_LOGS
+      lisp_t *expr = VEC_GET(&ast, i, lisp_t *);
       printf("\t[%lu]: ", i);
       lisp_print(stdout, expr);
       printf("\n");

src/reader.c

@@ -20,11 +20,12 @@ const char *read_err_to_cstr(read_err_t err)
     return "EOF";
   case READ_ERR_UNKNOWN_CHAR:
     return "UNKNOWN_CHAR";
-    break;
   case READ_ERR_EXPECTED_CLOSED_BRACE:
     return "EXPECTED_CLOSED_BRACE";
   case READ_ERR_EXPECTED_CLOSED_SQUARE_BRACKET:
     return "EXPECTED_CLOSED_SQUARE_BRACKET";
+  case READ_ERR_EXPECTED_CLOSING_SPEECHMARKS:
+    return "EXPECTED_CLOSING_SPEECHMARKS";
   case READ_ERR_UNEXPECTED_CLOSED_BRACE:
     return "UNEXPECTED_CLOSED_BRACE";
   case READ_ERR_UNEXPECTED_CLOSED_SQUARE_BRACKET:
@@ -37,7 +38,7 @@ const char *read_err_to_cstr(read_err_t err)
 // Accepted characters for symbols.
 static const char *SYMBOL_CHARS =
     "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz!$%&*+,-./"
-    ":<=>?@\\^_`{|}~0123456789";
+    ":<=>?@\\^_{|}~0123456789";
 
 // Little predicate using SYMBOL_CHARS
 bool is_sym(char c)
@@ -76,9 +77,9 @@ read_err_t read_int(sys_t *sys, stream_t *stream, lisp_t **ret)
     return read_sym(sys, stream, ret);
   }
 
-  if (digits_sv.size > 19)
+  if (digits_sv.size >= 18)
   {
-    TODO("alisp doesn't support big integers (bigger than 63 bits) yet");
+    TODO("alisp doesn't support big integers (bigger than 56 bits) yet");
   }
 
   i64 n = 0;
@@ -92,7 +93,7 @@ read_err_t read_int(sys_t *sys, stream_t *stream, lisp_t **ret)
     // => i > (INT_MAX - digit) / 10
     if (n > (INT_MAX - digit) / 10)
     {
-      TODO("alisp doesn't support big integers (bigger than 63 bits) yet");
+      TODO("alisp doesn't support big integers (bigger than 56 bits) yet");
     }
 
     n *= 10;
@@ -111,9 +112,7 @@ read_err_t read_negative(sys_t *sys, stream_t *stream, lisp_t **ret)
     read_err_t err = read_int(sys, stream, ret);
     if (err)
       return err;
-    i64 n = as_int(*ret);
-    n *= -1;
-    *ret = make_int(n);
+    *ret = make_int(as_smi(*ret) * -1);
     return READ_ERR_OK;
   }
   else if (is_sym(c) || isspace(c))
@@ -122,11 +121,14 @@ read_err_t read_negative(sys_t *sys, stream_t *stream, lisp_t **ret)
     return read_sym(sys, stream, ret);
   }
   else
+  {
     return READ_ERR_UNKNOWN_CHAR;
   }
+}
 
 read_err_t read_list(sys_t *sys, stream_t *stream, lisp_t **ret)
 {
+  u64 old_pos = stream->position;
   // skip past the open parentheses '('
   (void)stream_next(stream);
 
@@ -138,7 +140,7 @@ read_err_t read_list(sys_t *sys, stream_t *stream, lisp_t **ret)
     read_err_t err = read(sys, stream, &item);
     if (err == READ_ERR_EOF)
     {
-      return READ_ERR_EXPECTED_CLOSED_BRACE;
+      goto no_close_brace;
     }
     else if (err)
     {
@@ -157,16 +159,23 @@ read_err_t read_list(sys_t *sys, stream_t *stream, lisp_t **ret)
   }
 
   if (stream_peek(stream) != ')')
-    return READ_ERR_EXPECTED_CLOSED_BRACE;
+  {
+    goto no_close_brace;
+  }
 
   stream_next(stream);
   *ret = top;
   return READ_ERR_OK;
+no_close_brace:
+  stream->position = old_pos;
+  return READ_ERR_EXPECTED_CLOSED_BRACE;
 }
 
 read_err_t read_vec(sys_t *sys, stream_t *stream, lisp_t **ret)
 {
+  u64 old_pos = stream->position;
   (void)stream_next(stream);
+
   lisp_t *container = make_vec(sys, 0);
   while (!stream_eoc(stream) && stream_peek(stream) != ']')
   {
@@ -174,7 +183,7 @@ read_err_t read_vec(sys_t *sys, stream_t *stream, lisp_t **ret)
     read_err_t err = read(sys, stream, &item);
     if (err == READ_ERR_EOF)
     {
-      return READ_ERR_EXPECTED_CLOSED_BRACE;
+      goto no_close_square_bracket;
     }
     else if (err)
     {
@@ -187,10 +196,33 @@ read_err_t read_vec(sys_t *sys, stream_t *stream, lisp_t **ret)
   }
 
   if (stream_peek(stream) != ']')
-    return READ_ERR_EXPECTED_CLOSED_SQUARE_BRACKET;
+    goto no_close_square_bracket;
+
   stream_next(stream);
   *ret = container;
   return READ_ERR_OK;
+no_close_square_bracket:
+  stream->position = old_pos;
+  return READ_ERR_EXPECTED_CLOSED_SQUARE_BRACKET;
+}
+
+read_err_t read_str(sys_t *sys, stream_t *stream, lisp_t **ret)
+{
+  u64 old_pos = stream->position;
+
+  (void)stream_next(stream);
+  sv_t contents = stream_till(stream, "\"");
+  if (stream_eoc(stream) || stream_peek(stream) != '\"')
+  {
+    stream->position = old_pos;
+    return READ_ERR_EXPECTED_CLOSING_SPEECHMARKS;
+  }
+
+  stream_next(stream);
+  lisp_t *lisp = make_str(sys, contents.size);
+  vec_append(&as_str(lisp)->data, contents.data, contents.size);
+  *ret = lisp;
+  return READ_ERR_OK;
 }
 
 read_err_t read_quote(sys_t *sys, stream_t *stream, lisp_t **ret)
@@ -200,8 +232,8 @@ read_err_t read_quote(sys_t *sys, stream_t *stream, lisp_t **ret)
   read_err_t err = read(sys, stream, &to_quote);
   if (err)
     return err;
-  *ret = cons(sys, to_quote, NIL);
-  *ret = cons(sys, intern(sys, SV_AUTO("quote")), *ret);
+  lisp_t *items[] = {intern(sys, SV_AUTO("quote")), to_quote};
+  *ret            = make_list(sys, items, ARRSIZE(items));
   return READ_ERR_OK;
 }
 
@@ -243,6 +275,8 @@ read_err_t read(sys_t *sys, stream_t *stream, lisp_t **ret)
     return read_vec(sys, stream, ret);
   else if (c == ']')
     return READ_ERR_UNEXPECTED_CLOSED_SQUARE_BRACKET;
+  else if (c == '\"')
+    return read_str(sys, stream, ret);
 
   return READ_ERR_UNKNOWN_CHAR;
 }

src/string.c

@@ -0,0 +1,44 @@
+/* string.c: String library implementation
+ * Created: 2026-03-05
+ * Author: Aryadev Chavali
+ * License: See end of file
+ * Commentary:
+ */
+
+#include <string.h>
+
+#include <alisp/string.h>
+
+str_t string_make(sv_t sv)
+{
+  str_t string = {0};
+  if (sv.size)
+  {
+    vec_init(&string.data, sv.size);
+    if (sv.data)
+    {
+      memcpy(vec_data(&string.data), sv.data, sv.size);
+    }
+  }
+  return string;
+}
+
+sv_t string_sv(str_t *str)
+{
+  if (!str)
+    return SV(NULL, 0);
+  return SV((char *)vec_data(&str->data), str->data.size);
+}
+
+/* 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/>.
+
+ */

src/sys.c

@@ -0,0 +1,180 @@
+/* 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)
+{
+  static_assert(NUM_TAGS == 6);
+  switch (type)
+  {
+  case TAG_CONS:
+  case TAG_VEC:
+  case TAG_STR:
+    return alloc_make(&sys->memory, type);
+  // Shouldn't be allocated
+  case TAG_NIL:
+  case TAG_SMI:
+  case TAG_SYM:
+  default:
+    FAIL("Unreachable");
+  }
+  return NIL;
+}
+
+void sys_delete(sys_t *sys, lisp_t *lisp)
+{
+  alloc_delete(&sys->memory, lisp);
+}
+
+u64 sys_cost(sys_t *sys)
+{
+  return alloc_cost(&sys->memory) + sym_table_cost(&sys->symtable);
+}
+
+void sys_free(sys_t *sys)
+{
+  sym_table_free(&sys->symtable);
+  alloc_free(&sys->memory);
+  memset(sys, 0, sizeof(*sys));
+}
+
+lisp_t *make_int(i64 i)
+{
+  return tag_smi(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_list(sys_t *sys, lisp_t **lisps, u64 size)
+{
+  lisp_t *root = NIL;
+  for (u64 i = size; i > 0; --i)
+  {
+    lisp_t *node = lisps[i - 1];
+    root         = cons(sys, node, root);
+  }
+  return root;
+}
+
+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 *make_str(sys_t *sys, u64 capacity)
+{
+  lisp_t *str = sys_alloc(sys, TAG_STR);
+  vec_init(&as_str(str)->data, capacity);
+  return str;
+}
+
+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(sys_t *sys, lisp_t *lisp)
+{
+  static_assert(NUM_TAGS == 6);
+  switch (tag_get(lisp))
+  {
+  case TAG_STR:
+  case TAG_VEC:
+  case TAG_CONS:
+    // Delete the underlying data
+    alloc_delete(&sys->memory, lisp);
+    break;
+  case TAG_NIL:
+  case TAG_SMI:
+  case TAG_SYM:
+    // shouldn't be dealt with (either constant or dealt with elsewhere)
+    break;
+  }
+}
+
+void lisp_free_rec(sys_t *sys, lisp_t *item)
+{
+  static_assert(NUM_TAGS == 6);
+  switch (tag_get(item))
+  {
+  case TAG_CONS:
+  {
+    lisp_free_rec(sys, car(item));
+    lisp_free_rec(sys, cdr(item));
+    lisp_free(sys, item);
+    break;
+  }
+  case TAG_VEC:
+  {
+    vec_t *vec = as_vec(item);
+    FOR_VEC(i, vec, lisp_t *)
+    {
+      lisp_t *allocated = VEC_GET(vec, i, lisp_t *);
+      lisp_free_rec(sys, allocated);
+    }
+    lisp_free(sys, item);
+    break;
+  }
+  case TAG_STR:
+  {
+    lisp_free(sys, item);
+    break;
+  }
+  case TAG_NIL:
+  case TAG_SMI:
+  case TAG_SYM:
+    // 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/>.
+
+ */

src/tag.c

@@ -1,82 +0,0 @@
-/* tag.c: Pointer tagging
- * Created: 2025-08-19
- * Author: Aryadev Chavali
- * License: See end of file
- * Commentary:
- */
-
-#include <assert.h>
-#include <stdlib.h>
-
-#include <alisp/lisp.h>
-
-lisp_t *tag_int(i64 i)
-{
-  return TAG((u64)i, INT);
-}
-
-lisp_t *tag_sym(const char *str)
-{
-  return TAG((u64)str, SYM);
-}
-
-lisp_t *tag_vec(const vec_t *vec)
-{
-  return TAG((u64)vec, VEC);
-}
-
-lisp_t *tag_cons(const cons_t *cons)
-{
-  return TAG((u64)cons, CONS);
-}
-
-tag_t get_tag(const lisp_t *lisp)
-{
-  static_assert(NUM_TAGS == 5);
-  if (!lisp)
-    return TAG_NIL;
-  else if (IS_TAG(lisp, INT))
-    return TAG_INT;
-
-  return (u64)lisp & 0xFF;
-}
-
-i64 as_int(lisp_t *obj)
-{
-  assert(IS_TAG(obj, INT));
-  u64 p_obj = (u64)obj;
-  return UNTAG(p_obj, INT) |               // Delete the tag
-         (NTH_BYTE(p_obj, 7) & 0x80) << 56 // duplicate the MSB (preserve sign)
-      ;
-}
-
-char *as_sym(lisp_t *obj)
-{
-  assert(IS_TAG(obj, SYM));
-  return (char *)UNTAG(obj, SYM);
-}
-
-cons_t *as_cons(lisp_t *obj)
-{
-  assert(IS_TAG(obj, CONS));
-  return (cons_t *)UNTAG(obj, CONS);
-}
-
-vec_t *as_vec(lisp_t *obj)
-{
-  assert(IS_TAG(obj, VEC));
-  return (vec_t *)UNTAG(obj, VEC);
-}
-
-/* Copyright (C) 2025, 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/>.
-
- */

src/vec.c

@@ -38,6 +38,14 @@ void vec_free(vec_t *vec)
   memset(vec, 0, sizeof(*vec));
 }
 
+void vec_reset(vec_t *vec)
+{
+  if (!vec)
+    return;
+  memset(vec_data(vec), 0, vec->capacity);
+  vec->size = 0;
+}
+
 u8 *vec_data(vec_t *vec)
 {
   return vec->not_inlined ? vec->ptr : vec->inlined;
@@ -81,10 +89,24 @@ void vec_append(vec_t *vec, const void *const ptr, u64 size)
   if (!vec)
     return;
   vec_ensure_free(vec, size);
+  if (ptr)
     memcpy(vec_data(vec) + vec->size, ptr, size);
   vec->size += size;
 }
 
+bool vec_try_append(vec_t *vec, const void *const ptr, u64 size)
+{
+  if (!vec || vec->capacity - vec->size < size)
+    return false;
+  if (ptr)
+  {
+    void *newptr = vec_data(vec) + vec->size;
+    memcpy(newptr, ptr, size);
+  }
+  vec->size += size;
+  return true;
+}
+
 void vec_clone(vec_t *dest, vec_t *src)
 {
   if (!src || !dest)

test/test_lisp_api.c

@@ -23,7 +23,7 @@ void smi_test(void)
   {
     i64 in       = ints[i];
     lisp_t *lisp = make_int(in);
-    i64 out      = as_int(lisp);
+    i64 out      = as_smi(lisp);
 
     TEST(in == out, "%ld == %ld", in, out);
   }
@@ -47,7 +47,7 @@ void smi_oob_test(void)
   {
     i64 in       = ints[i];
     lisp_t *lisp = make_int(in);
-    i64 out      = as_int(lisp);
+    i64 out      = as_smi(lisp);
 
     TEST(in != out, "%ld != %ld", in, out);
   }

test/test_stream.c

@@ -54,7 +54,7 @@ void stream_test_prologue(void)
 
 void stream_test_epilogue(void)
 {
-  TEST_INFO("Freeing resources and deleting file `%s`\n", valid_filename);
+  TEST_INFO("Deleting file `%s`\n", valid_filename);
   assert(valid_fp);
   fclose(valid_fp);
   remove(valid_filename);