diff --git a/include/chibi/sexp.h b/include/chibi/sexp.h
index b5713356..45778bbb 100755
--- a/include/chibi/sexp.h
+++ b/include/chibi/sexp.h
@@ -276,7 +276,7 @@ struct sexp_type_struct {
   unsigned short size_scale;
   short weak_base, weak_len_base, weak_len_off, weak_len_scale, weak_len_extra;
   short depth;
-  sexp name, cpl, slots, dl, id, print;
+  sexp name, cpl, slots, getters, setters, dl, id, print;
   sexp_proc2 finalize;
 };
 
@@ -1159,6 +1159,8 @@ SEXP_API sexp sexp_symbol_table[SEXP_SYMBOL_TABLE_SIZE];
 #define sexp_type_name(x)              (sexp_field(x, type, SEXP_TYPE, name))
 #define sexp_type_cpl(x)               (sexp_field(x, type, SEXP_TYPE, cpl))
 #define sexp_type_slots(x)             (sexp_field(x, type, SEXP_TYPE, slots))
+#define sexp_type_getters(x)           (sexp_field(x, type, SEXP_TYPE, getters))
+#define sexp_type_setters(x)           (sexp_field(x, type, SEXP_TYPE, setters))
 #define sexp_type_finalize(x)          (sexp_field(x, type, SEXP_TYPE, finalize))
 #define sexp_type_print(x)             (sexp_field(x, type, SEXP_TYPE, print))
 #define sexp_type_dl(x)                (sexp_field(x, type, SEXP_TYPE, dl))
diff --git a/sexp.c b/sexp.c
index a2c093be..58eeee50 100644
--- a/sexp.c
+++ b/sexp.c
@@ -184,57 +184,57 @@ sexp sexp_finalize_dl (sexp ctx, sexp self, sexp_sint_t n, sexp dl) {
 #endif
 
 static struct sexp_type_struct _sexp_type_specs[] = {
-  {SEXP_OBJECT, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, (sexp)"Object", SEXP_FALSE, SEXP_FALSE, NULL, SEXP_FALSE, NULL, NULL},
-  {SEXP_TYPE, sexp_offsetof(type, name), 5+SEXP_USE_DL, 5+SEXP_USE_DL, 0, 0, sexp_sizeof(type), 0, 0, 0, 0, 0, 0, 0, 0, (sexp)"Type", SEXP_FALSE, SEXP_FALSE, NULL, SEXP_FALSE, NULL, NULL},
-  {SEXP_FIXNUM, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, (sexp)"Integer", SEXP_FALSE, SEXP_FALSE, NULL, SEXP_FALSE, NULL, NULL},
-  {SEXP_NUMBER, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, (sexp)"Number", SEXP_FALSE, SEXP_FALSE, NULL, SEXP_FALSE, NULL, NULL},
-  {SEXP_CHAR, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, (sexp)"Char", SEXP_FALSE, SEXP_FALSE, NULL, SEXP_FALSE, NULL, NULL},
-  {SEXP_BOOLEAN, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, (sexp)"Boolean", SEXP_FALSE, SEXP_FALSE, NULL, SEXP_FALSE, NULL, NULL},
-  {SEXP_PAIR, sexp_offsetof(pair, car), 2, 3, 0, 0, sexp_sizeof(pair), 0, 0, 0, 0, 0, 0, 0, 0, (sexp)"Pair", SEXP_FALSE, SEXP_FALSE, NULL, SEXP_FALSE, NULL, NULL},
-  {SEXP_SYMBOL, 0, 0, 0, 0, 0, sexp_sizeof(symbol)+1, sexp_offsetof(symbol, length), 1, 0, 0, 0, 0, 0, 0, (sexp)"Symbol", SEXP_FALSE, SEXP_FALSE, NULL, SEXP_FALSE, NULL, NULL},
-  {SEXP_BYTES, 0, 0, 0, 0, 0, sexp_sizeof(bytes)+1, sexp_offsetof(bytes, length), 1, 0, 0, 0, 0, 0, 0, (sexp)"Byte-Vector", SEXP_FALSE, SEXP_FALSE, NULL, SEXP_FALSE, NULL, NULL},
+  {SEXP_OBJECT, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, (sexp)"Object", SEXP_FALSE, SEXP_FALSE, SEXP_FALSE, SEXP_FALSE, NULL, SEXP_FALSE, NULL, NULL},
+  {SEXP_TYPE, sexp_offsetof(type, name), 7+SEXP_USE_DL, 7+SEXP_USE_DL, 0, 0, sexp_sizeof(type), 0, 0, 0, 0, 0, 0, 0, 0, (sexp)"Type", SEXP_FALSE, SEXP_FALSE, SEXP_FALSE, SEXP_FALSE, NULL, SEXP_FALSE, NULL, NULL},
+  {SEXP_FIXNUM, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, (sexp)"Integer", SEXP_FALSE, SEXP_FALSE, SEXP_FALSE, SEXP_FALSE, NULL, SEXP_FALSE, NULL, NULL},
+  {SEXP_NUMBER, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, (sexp)"Number", SEXP_FALSE, SEXP_FALSE, SEXP_FALSE, SEXP_FALSE, NULL, SEXP_FALSE, NULL, NULL},
+  {SEXP_CHAR, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, (sexp)"Char", SEXP_FALSE, SEXP_FALSE, SEXP_FALSE, SEXP_FALSE, NULL, SEXP_FALSE, NULL, NULL},
+  {SEXP_BOOLEAN, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, (sexp)"Boolean", SEXP_FALSE, SEXP_FALSE, SEXP_FALSE, SEXP_FALSE, NULL, SEXP_FALSE, NULL, NULL},
+  {SEXP_PAIR, sexp_offsetof(pair, car), 2, 3, 0, 0, sexp_sizeof(pair), 0, 0, 0, 0, 0, 0, 0, 0, (sexp)"Pair", SEXP_FALSE, SEXP_FALSE, SEXP_FALSE, SEXP_FALSE, NULL, SEXP_FALSE, NULL, NULL},
+  {SEXP_SYMBOL, 0, 0, 0, 0, 0, sexp_sizeof(symbol)+1, sexp_offsetof(symbol, length), 1, 0, 0, 0, 0, 0, 0, (sexp)"Symbol", SEXP_FALSE, SEXP_FALSE, SEXP_FALSE, SEXP_FALSE, NULL, SEXP_FALSE, NULL, NULL},
+  {SEXP_BYTES, 0, 0, 0, 0, 0, sexp_sizeof(bytes)+1, sexp_offsetof(bytes, length), 1, 0, 0, 0, 0, 0, 0, (sexp)"Byte-Vector", SEXP_FALSE, SEXP_FALSE, SEXP_FALSE, SEXP_FALSE, NULL, SEXP_FALSE, NULL, NULL},
 #if SEXP_USE_PACKED_STRINGS
-  {SEXP_STRING, 0, 0, 0, 0, 0, sexp_sizeof(string)+1, sexp_offsetof(string, length), 1, 0, 0, 0, 0, 0, 0, (sexp)"String", SEXP_FALSE, SEXP_FALSE, NULL, SEXP_FALSE, NULL, NULL},
+  {SEXP_STRING, 0, 0, 0, 0, 0, sexp_sizeof(string)+1, sexp_offsetof(string, length), 1, 0, 0, 0, 0, 0, 0, (sexp)"String", SEXP_FALSE, SEXP_FALSE, SEXP_FALSE, SEXP_FALSE, NULL, SEXP_FALSE, NULL, NULL},
 #else
-  {SEXP_STRING, sexp_offsetof(string, bytes), 1, 1, 0, 0, sexp_sizeof(string), 0, 0, 0, 0, 0, 0, 0, 0, (sexp)"String", SEXP_FALSE, SEXP_FALSE, NULL, SEXP_FALSE, NULL, NULL},
+  {SEXP_STRING, sexp_offsetof(string, bytes), 1, 1, 0, 0, sexp_sizeof(string), 0, 0, 0, 0, 0, 0, 0, 0, (sexp)"String", SEXP_FALSE, SEXP_FALSE, SEXP_FALSE, SEXP_FALSE, NULL, SEXP_FALSE, NULL, NULL},
 #endif
-  {SEXP_VECTOR, sexp_offsetof(vector, data), 0, 0, sexp_offsetof(vector, length), 1, sexp_sizeof(vector), sexp_offsetof(vector, length), sizeof(sexp), 0, 0, 0, 0, 0, 0, (sexp)"Vector", SEXP_FALSE, SEXP_FALSE, NULL, SEXP_FALSE, NULL, NULL},
-  {SEXP_FLONUM, 0, 0, 0, 0, 0, sexp_sizeof(flonum), 0, 0, 0, 0, 0, 0, 0, 0, (sexp)"Flonum", SEXP_FALSE, SEXP_FALSE, NULL, SEXP_FALSE, NULL, NULL},
-  {SEXP_BIGNUM, 0, 0, 0, 0, 0, sexp_sizeof(bignum), sexp_offsetof(bignum, length), sizeof(sexp_uint_t), 0, 0, 0, 0, 0, 0, (sexp)"Bignum", SEXP_FALSE, SEXP_FALSE, NULL, SEXP_FALSE, NULL, NULL},
+  {SEXP_VECTOR, sexp_offsetof(vector, data), 0, 0, sexp_offsetof(vector, length), 1, sexp_sizeof(vector), sexp_offsetof(vector, length), sizeof(sexp), 0, 0, 0, 0, 0, 0, (sexp)"Vector", SEXP_FALSE, SEXP_FALSE, SEXP_FALSE, SEXP_FALSE, NULL, SEXP_FALSE, NULL, NULL},
+  {SEXP_FLONUM, 0, 0, 0, 0, 0, sexp_sizeof(flonum), 0, 0, 0, 0, 0, 0, 0, 0, (sexp)"Flonum", SEXP_FALSE, SEXP_FALSE, SEXP_FALSE, SEXP_FALSE, NULL, SEXP_FALSE, NULL, NULL},
+  {SEXP_BIGNUM, 0, 0, 0, 0, 0, sexp_sizeof(bignum), sexp_offsetof(bignum, length), sizeof(sexp_uint_t), 0, 0, 0, 0, 0, 0, (sexp)"Bignum", SEXP_FALSE, SEXP_FALSE, SEXP_FALSE, SEXP_FALSE, NULL, SEXP_FALSE, NULL, NULL},
 #if SEXP_USE_RATIOS
-  {SEXP_RATIO, sexp_offsetof(ratio, numerator), 2, 2, 0, 0, sexp_sizeof(ratio), 0, 0, 0, 0, 0, 0, 0, 0, (sexp)"Ratio", SEXP_FALSE, SEXP_FALSE, NULL, SEXP_FALSE, NULL, NULL},
+  {SEXP_RATIO, sexp_offsetof(ratio, numerator), 2, 2, 0, 0, sexp_sizeof(ratio), 0, 0, 0, 0, 0, 0, 0, 0, (sexp)"Ratio", SEXP_FALSE, SEXP_FALSE, SEXP_FALSE, SEXP_FALSE, NULL, SEXP_FALSE, NULL, NULL},
 #endif
 #if SEXP_USE_COMPLEX
-  {SEXP_COMPLEX, sexp_offsetof(complex, real), 2, 2, 0, 0, sexp_sizeof(complex), 0, 0, 0, 0, 0, 0, 0, 0, (sexp)"Complex", SEXP_FALSE, SEXP_FALSE, NULL, SEXP_FALSE, NULL, NULL},
+  {SEXP_COMPLEX, sexp_offsetof(complex, real), 2, 2, 0, 0, sexp_sizeof(complex), 0, 0, 0, 0, 0, 0, 0, 0, (sexp)"Complex", SEXP_FALSE, SEXP_FALSE, SEXP_FALSE, SEXP_FALSE, NULL, SEXP_FALSE, NULL, NULL},
 #endif
-  {SEXP_IPORT, sexp_offsetof(port, name), 3, 3, 0, 0, sexp_sizeof(port), 0, 0, 0, 0, 0, 0, 0, 0, (sexp)"Input-Port", SEXP_FALSE, SEXP_FALSE, NULL, SEXP_FALSE, NULL, SEXP_FINALIZE_PORT},
-  {SEXP_OPORT, sexp_offsetof(port, name), 3, 3, 0, 0, sexp_sizeof(port), 0, 0, 0, 0, 0, 0, 0, 0, (sexp)"Output-Port", SEXP_FALSE, SEXP_FALSE, NULL, SEXP_FALSE, NULL, SEXP_FINALIZE_PORT},
-  {SEXP_FILENO, 0, 0, 0, 0, 0, sexp_sizeof(fileno), 0, 0, 0, 0, 0, 0, 0, 0, (sexp)"File-Descriptor", SEXP_FALSE, SEXP_FALSE, NULL, SEXP_FALSE, NULL, SEXP_FINALIZE_FILENO},
-  {SEXP_EXCEPTION, sexp_offsetof(exception, kind), 6, 6, 0, 0, sexp_sizeof(exception), 0, 0, 0, 0, 0, 0, 0, 0, (sexp)"Exception", SEXP_FALSE, SEXP_FALSE, NULL, SEXP_FALSE, (sexp)sexp_write_simple_object, NULL},
-  {SEXP_PROCEDURE, sexp_offsetof(procedure, bc), 2, 2, 0, 0, sexp_sizeof(procedure), 0, 0, 0, 0, 0, 0, 0, 0, (sexp)"Procedure", SEXP_FALSE, SEXP_FALSE, NULL, SEXP_FALSE, NULL, NULL},
-  {SEXP_MACRO, sexp_offsetof(macro, proc), 3, 3, 0, 0, sexp_sizeof(macro), 0, 0, 0, 0, 0, 0, 0, 0, (sexp)"Macro", SEXP_FALSE, SEXP_FALSE, NULL, SEXP_FALSE, NULL, NULL},
-  {SEXP_SYNCLO, sexp_offsetof(synclo, env), 3, 3, 0, 0, sexp_sizeof(synclo), 0, 0, 0, 0, 0, 0, 0, 0, (sexp)"Syntactic-Closure", SEXP_FALSE, SEXP_FALSE, NULL, SEXP_FALSE, (sexp)sexp_write_simple_object, NULL},
-  {SEXP_ENV, sexp_offsetof(env, parent), 3+SEXP_USE_RENAME_BINDINGS, 3+SEXP_USE_RENAME_BINDINGS, 0, 0, sexp_sizeof(env), 0, 0, 0, 0, 0, 0, 0, 0, (sexp)"Environment", SEXP_FALSE, SEXP_FALSE, NULL, SEXP_FALSE, NULL, NULL},
-  {SEXP_BYTECODE, sexp_offsetof(bytecode, name), 3, 3, 0, 0, sexp_sizeof(bytecode), offsetof(struct sexp_struct, value.bytecode.length), 1, 0, 0, 0, 0, 0, 0, (sexp)"Bytecode", SEXP_FALSE, SEXP_FALSE, NULL, SEXP_FALSE, NULL, NULL},
-  {SEXP_CORE, sexp_offsetof(core, name), 1, 1, 0, 0, sexp_sizeof(core), 0, 0, 0, 0, 0, 0, 0, 0, (sexp)"Core-Form", SEXP_FALSE, SEXP_FALSE, NULL, SEXP_FALSE, NULL, NULL},
+  {SEXP_IPORT, sexp_offsetof(port, name), 3, 3, 0, 0, sexp_sizeof(port), 0, 0, 0, 0, 0, 0, 0, 0, (sexp)"Input-Port", SEXP_FALSE, SEXP_FALSE, SEXP_FALSE, SEXP_FALSE, NULL, SEXP_FALSE, NULL, SEXP_FINALIZE_PORT},
+  {SEXP_OPORT, sexp_offsetof(port, name), 3, 3, 0, 0, sexp_sizeof(port), 0, 0, 0, 0, 0, 0, 0, 0, (sexp)"Output-Port", SEXP_FALSE, SEXP_FALSE, SEXP_FALSE, SEXP_FALSE, NULL, SEXP_FALSE, NULL, SEXP_FINALIZE_PORT},
+  {SEXP_FILENO, 0, 0, 0, 0, 0, sexp_sizeof(fileno), 0, 0, 0, 0, 0, 0, 0, 0, (sexp)"File-Descriptor", SEXP_FALSE, SEXP_FALSE, SEXP_FALSE, SEXP_FALSE, NULL, SEXP_FALSE, NULL, SEXP_FINALIZE_FILENO},
+  {SEXP_EXCEPTION, sexp_offsetof(exception, kind), 6, 6, 0, 0, sexp_sizeof(exception), 0, 0, 0, 0, 0, 0, 0, 0, (sexp)"Exception", SEXP_FALSE, SEXP_FALSE, SEXP_FALSE, SEXP_FALSE, NULL, SEXP_FALSE, (sexp)sexp_write_simple_object, NULL},
+  {SEXP_PROCEDURE, sexp_offsetof(procedure, bc), 2, 2, 0, 0, sexp_sizeof(procedure), 0, 0, 0, 0, 0, 0, 0, 0, (sexp)"Procedure", SEXP_FALSE, SEXP_FALSE, SEXP_FALSE, SEXP_FALSE, NULL, SEXP_FALSE, NULL, NULL},
+  {SEXP_MACRO, sexp_offsetof(macro, proc), 3, 3, 0, 0, sexp_sizeof(macro), 0, 0, 0, 0, 0, 0, 0, 0, (sexp)"Macro", SEXP_FALSE, SEXP_FALSE, SEXP_FALSE, SEXP_FALSE, NULL, SEXP_FALSE, NULL, NULL},
+  {SEXP_SYNCLO, sexp_offsetof(synclo, env), 3, 3, 0, 0, sexp_sizeof(synclo), 0, 0, 0, 0, 0, 0, 0, 0, (sexp)"Syntactic-Closure", SEXP_FALSE, SEXP_FALSE, SEXP_FALSE, SEXP_FALSE, NULL, SEXP_FALSE, (sexp)sexp_write_simple_object, NULL},
+  {SEXP_ENV, sexp_offsetof(env, parent), 3+SEXP_USE_RENAME_BINDINGS, 3+SEXP_USE_RENAME_BINDINGS, 0, 0, sexp_sizeof(env), 0, 0, 0, 0, 0, 0, 0, 0, (sexp)"Environment", SEXP_FALSE, SEXP_FALSE, SEXP_FALSE, SEXP_FALSE, NULL, SEXP_FALSE, NULL, NULL},
+  {SEXP_BYTECODE, sexp_offsetof(bytecode, name), 3, 3, 0, 0, sexp_sizeof(bytecode), offsetof(struct sexp_struct, value.bytecode.length), 1, 0, 0, 0, 0, 0, 0, (sexp)"Bytecode", SEXP_FALSE, SEXP_FALSE, SEXP_FALSE, SEXP_FALSE, NULL, SEXP_FALSE, NULL, NULL},
+  {SEXP_CORE, sexp_offsetof(core, name), 1, 1, 0, 0, sexp_sizeof(core), 0, 0, 0, 0, 0, 0, 0, 0, (sexp)"Core-Form", SEXP_FALSE, SEXP_FALSE, SEXP_FALSE, SEXP_FALSE, NULL, SEXP_FALSE, NULL, NULL},
 #if SEXP_USE_DL
-  {SEXP_DL, sexp_offsetof(dl, file), 1, 1, 0, 0, sexp_sizeof(dl), 0, 0, 0, 0, 0, 0, 0, 0, (sexp)"Dynamic-Library", SEXP_FALSE, SEXP_FALSE, NULL, SEXP_FALSE, NULL, SEXP_FINALIZE_DL},
+  {SEXP_DL, sexp_offsetof(dl, file), 1, 1, 0, 0, sexp_sizeof(dl), 0, 0, 0, 0, 0, 0, 0, 0, (sexp)"Dynamic-Library", SEXP_FALSE, SEXP_FALSE, SEXP_FALSE, SEXP_FALSE, NULL, SEXP_FALSE, NULL, SEXP_FINALIZE_DL},
 #endif
-  {SEXP_OPCODE, sexp_offsetof(opcode, name), 11, 11, 0, 0, sexp_sizeof(opcode), 0, 0, 0, 0, 0, 0, 0, 0, (sexp)"Opcode", SEXP_FALSE, SEXP_FALSE, NULL, SEXP_FALSE, NULL, NULL},
-  {SEXP_LAMBDA, sexp_offsetof(lambda, name), 11, 11, 0, 0, sexp_sizeof(lambda), 0, 0, 0, 0, 0, 0, 0, 0, (sexp)"Lambda", SEXP_FALSE, SEXP_FALSE, NULL, SEXP_FALSE, (sexp)sexp_write_simple_object, NULL},
-  {SEXP_CND, sexp_offsetof(cnd, test), 4, 4, 0, 0, sexp_sizeof(cnd), 0, 0, 0, 0, 0, 0, 0, 0, (sexp)"Conditional", SEXP_FALSE, SEXP_FALSE, NULL, SEXP_FALSE, (sexp)sexp_write_simple_object, NULL},
-  {SEXP_REF, sexp_offsetof(ref, name), 3, 3, 0, 0, sexp_sizeof(ref), 0, 0, 0, 0, 0, 0, 0, 0, (sexp)"Reference", SEXP_FALSE, SEXP_FALSE, NULL, SEXP_FALSE, (sexp)sexp_write_simple_object, NULL},
-  {SEXP_SET, sexp_offsetof(set, var), 3, 3, 0, 0, sexp_sizeof(set), 0, 0, 0, 0, 0, 0, 0, 0, (sexp)"Set!", SEXP_FALSE, SEXP_FALSE, NULL, SEXP_FALSE, (sexp)sexp_write_simple_object, NULL},
-  {SEXP_SEQ, sexp_offsetof(seq, ls), 2, 2, 0, 0, sexp_sizeof(seq), 0, 0, 0, 0, 0, 0, 0, 0, (sexp)"Sequence", SEXP_FALSE, SEXP_FALSE, NULL, SEXP_FALSE, (sexp)sexp_write_simple_object, NULL},
-  {SEXP_LIT, sexp_offsetof(lit, value), 2, 2, 0, 0, sexp_sizeof(lit), 0, 0, 0, 0, 0, 0, 0, 0, (sexp)"Literal", SEXP_FALSE, SEXP_FALSE, NULL, SEXP_FALSE, (sexp)sexp_write_simple_object, NULL},
-  {SEXP_STACK, sexp_offsetof(stack, data), 1, 1, sexp_offsetof(stack, top), 1, sexp_sizeof(stack), offsetof(struct sexp_struct, value.stack.length), sizeof(sexp), 0, 0, 0, 0, 0, 0, (sexp)"Stack", SEXP_FALSE, SEXP_FALSE, NULL, SEXP_FALSE, NULL, NULL},
-  {SEXP_CONTEXT, sexp_offsetof(context, stack), 12+SEXP_USE_DL, 12+SEXP_USE_DL, 0, 0, sexp_sizeof(context), 0, 0, 0, 0, 0, 0, 0, 0, (sexp)"Context", SEXP_FALSE, SEXP_FALSE, NULL, SEXP_FALSE, NULL, NULL},
-  {SEXP_CPOINTER, sexp_offsetof(cpointer, parent), 1, 0, 0, 0, sexp_sizeof(cpointer), sexp_offsetof(cpointer, length), 1, 0, 0, 0, 0, 0, 0, (sexp)"Cpointer", SEXP_FALSE, SEXP_FALSE, NULL, SEXP_FALSE, NULL, NULL},
+  {SEXP_OPCODE, sexp_offsetof(opcode, name), 11, 11, 0, 0, sexp_sizeof(opcode), 0, 0, 0, 0, 0, 0, 0, 0, (sexp)"Opcode", SEXP_FALSE, SEXP_FALSE, SEXP_FALSE, SEXP_FALSE, NULL, SEXP_FALSE, NULL, NULL},
+  {SEXP_LAMBDA, sexp_offsetof(lambda, name), 11, 11, 0, 0, sexp_sizeof(lambda), 0, 0, 0, 0, 0, 0, 0, 0, (sexp)"Lambda", SEXP_FALSE, SEXP_FALSE, SEXP_FALSE, SEXP_FALSE, NULL, SEXP_FALSE, (sexp)sexp_write_simple_object, NULL},
+  {SEXP_CND, sexp_offsetof(cnd, test), 4, 4, 0, 0, sexp_sizeof(cnd), 0, 0, 0, 0, 0, 0, 0, 0, (sexp)"Conditional", SEXP_FALSE, SEXP_FALSE, SEXP_FALSE, SEXP_FALSE, NULL, SEXP_FALSE, (sexp)sexp_write_simple_object, NULL},
+  {SEXP_REF, sexp_offsetof(ref, name), 3, 3, 0, 0, sexp_sizeof(ref), 0, 0, 0, 0, 0, 0, 0, 0, (sexp)"Reference", SEXP_FALSE, SEXP_FALSE, SEXP_FALSE, SEXP_FALSE, NULL, SEXP_FALSE, (sexp)sexp_write_simple_object, NULL},
+  {SEXP_SET, sexp_offsetof(set, var), 3, 3, 0, 0, sexp_sizeof(set), 0, 0, 0, 0, 0, 0, 0, 0, (sexp)"Set!", SEXP_FALSE, SEXP_FALSE, SEXP_FALSE, SEXP_FALSE, NULL, SEXP_FALSE, (sexp)sexp_write_simple_object, NULL},
+  {SEXP_SEQ, sexp_offsetof(seq, ls), 2, 2, 0, 0, sexp_sizeof(seq), 0, 0, 0, 0, 0, 0, 0, 0, (sexp)"Sequence", SEXP_FALSE, SEXP_FALSE, SEXP_FALSE, SEXP_FALSE, NULL, SEXP_FALSE, (sexp)sexp_write_simple_object, NULL},
+  {SEXP_LIT, sexp_offsetof(lit, value), 2, 2, 0, 0, sexp_sizeof(lit), 0, 0, 0, 0, 0, 0, 0, 0, (sexp)"Literal", SEXP_FALSE, SEXP_FALSE, SEXP_FALSE, SEXP_FALSE, NULL, SEXP_FALSE, (sexp)sexp_write_simple_object, NULL},
+  {SEXP_STACK, sexp_offsetof(stack, data), 1, 1, sexp_offsetof(stack, top), 1, sexp_sizeof(stack), offsetof(struct sexp_struct, value.stack.length), sizeof(sexp), 0, 0, 0, 0, 0, 0, (sexp)"Stack", SEXP_FALSE, SEXP_FALSE, SEXP_FALSE, SEXP_FALSE, NULL, SEXP_FALSE, NULL, NULL},
+  {SEXP_CONTEXT, sexp_offsetof(context, stack), 12+SEXP_USE_DL, 12+SEXP_USE_DL, 0, 0, sexp_sizeof(context), 0, 0, 0, 0, 0, 0, 0, 0, (sexp)"Context", SEXP_FALSE, SEXP_FALSE, SEXP_FALSE, SEXP_FALSE, NULL, SEXP_FALSE, NULL, NULL},
+  {SEXP_CPOINTER, sexp_offsetof(cpointer, parent), 1, 0, 0, 0, sexp_sizeof(cpointer), sexp_offsetof(cpointer, length), 1, 0, 0, 0, 0, 0, 0, (sexp)"Cpointer", SEXP_FALSE, SEXP_FALSE, SEXP_FALSE, SEXP_FALSE, NULL, SEXP_FALSE, NULL, NULL},
 #if SEXP_USE_AUTO_FORCE
-  {SEXP_PROMISE, sexp_offsetof(promise, value), 1, 1, 0, 0, sexp_sizeof(promise), 0, 0, 0, 0, 0, 0, 0, 0, (sexp)"Promise", SEXP_FALSE, SEXP_FALSE, NULL, SEXP_FALSE, NULL, NULL},
+  {SEXP_PROMISE, sexp_offsetof(promise, value), 1, 1, 0, 0, sexp_sizeof(promise), 0, 0, 0, 0, 0, 0, 0, 0, (sexp)"Promise", SEXP_FALSE, SEXP_FALSE, SEXP_FALSE, SEXP_FALSE, NULL, SEXP_FALSE, NULL, NULL},
 #endif
 #if SEXP_USE_WEAK_REFERENCES
-  {SEXP_EPHEMERON, sexp_offsetof(lit, value), 0, 0, 0, 0, sizeof(sexp), 0, 0, sexp_offsetof(lit, value), 1, 0, 0, 1, 0, (sexp)"Ephemeron", SEXP_FALSE, SEXP_FALSE, NULL, SEXP_FALSE, NULL, NULL},
+  {SEXP_EPHEMERON, sexp_offsetof(lit, value), 0, 0, 0, 0, sizeof(sexp), 0, 0, sexp_offsetof(lit, value), 1, 0, 0, 1, 0, (sexp)"Ephemeron", SEXP_FALSE, SEXP_FALSE, SEXP_FALSE, SEXP_FALSE, NULL, SEXP_FALSE, NULL, NULL},
 #endif
 };
 
@@ -291,6 +291,8 @@ sexp sexp_register_type_op (sexp ctx, sexp self, sexp_sint_t n, sexp name,
       sexp_type_weak_len_scale(type) = sexp_unbox_fixnum(ws);
       sexp_type_weak_len_extra(type) = sexp_unbox_fixnum(we);
       sexp_type_name(type) = name;
+      sexp_type_getters(type) = SEXP_FALSE;
+      sexp_type_setters(type) = SEXP_FALSE;
       sexp_type_finalize(type) = f;
       sexp_type_id(type) = SEXP_FALSE;
 #if SEXP_USE_DL
diff --git a/tools/chibi-ffi b/tools/chibi-ffi
index 22c7c9d9..9959a32f 100755
--- a/tools/chibi-ffi
+++ b/tools/chibi-ffi
@@ -31,8 +31,10 @@
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 ;; globals
 
-(define *ffi-version* "0.2")
+(define *ffi-version* "0.3")
 (define *types* '())
+(define *type-getters* '())
+(define *type-setters* '())
 (define *typedefs* '())
 (define *funcs* '())
 (define *methods* '())
@@ -108,8 +110,8 @@
 
 (define (struct-fields ls)
   (let lp ((ls ls) (res '()))
-    (cond ((null? ls) (reverse res))
-          ((symbol? (car ls)) (lp (cddr ls) res))
+    (cond ((not (pair? ls)) (reverse res))
+          ((symbol? (car ls)) (lp (if (pair? (cdr ls)) (cddr ls) (cdr ls)) res))
           (else (lp (cdr ls) (cons (car ls) res))))))
 
 (define (lookup-type type)
@@ -1439,7 +1441,24 @@
                 (type-id-init-value (car ls)) ");\n")))))
      ;; "  } else {\n"
      ;; "    sexp_warn(ctx, \"couldn't generated opcode\", " var ");\n"
-     "  }\n"))))
+     "  }\n")))
+  (cond
+   ((assq (func-scheme-name func) *type-getters*)
+    => (lambda (x)
+         (let ((name (cadr x))
+               (i (car (cddr x))))
+           (cat "  if (sexp_vectorp(sexp_type_getters(" (type-id-name name)
+                "))) sexp_vector_set(sexp_type_getters("
+                (type-id-name name) "), "
+                (make-integer i) ", " var ");\n"))))
+   ((assq (func-scheme-name func) *type-setters*)
+    => (lambda (x)
+         (let ((name (cadr x))
+               (i (car (cddr x))))
+           (cat "  if (sexp_vectorp(sexp_type_setters(" (type-id-name name)
+                "))) sexp_vector_set(sexp_type_setters("
+                (type-id-name name) "), "
+                (make-integer i) ", " var ");\n"))))))
 
 (define (write-func-binding func . o)
   (let ((var (if (pair? o) (car o) "op")))
@@ -1463,9 +1482,9 @@
              (write-func-types var (car ls)))))
        "  }\n"))
 
-(define (write-type type)
-  (let* ((name (car type))
-         (type (cdr type))
+(define (write-type orig-type)
+  (let* ((name (car orig-type))
+         (type (cdr orig-type))
          (imported? (cond ((member 'imported?: type) => cadr) (else #f))))
     (cond
      (imported?
@@ -1487,6 +1506,16 @@
            ");\n"
            "  tmp = sexp_string_to_symbol(ctx, name);\n"
            "  sexp_env_define(ctx, env, tmp, " (type-id-name name) ");\n")
+      (if (pair? (struct-fields type))
+          (let ((len (make-integer (length (struct-fields type))))
+                (getters (string-append "sexp_type_getters("
+                                        (x->string (type-id-name name)) ")"))
+                (setters (string-append "sexp_type_setters("
+                                        (x->string (type-id-name name)) ")")))
+            (cat "  " getters
+                 " = sexp_make_vector(ctx, " len ", SEXP_FALSE);\n"
+                 "  " setters
+                 " = sexp_make_vector(ctx, " len ", SEXP_FALSE);\n")))
       (cond
        ((memq 'predicate: type)
         => (lambda (x)
@@ -1649,35 +1678,45 @@
                                       args)))
                        *funcs*))))))
   ;; write field accessors
-  (for-each
-   (lambda (field)
-     (cond
-      ((and (pair? field) (pair? (cdr field)))
-       (cond
-        ((and (pair? (cddr field)) (car (cddr field)))
-         (write-type-getter type name field)
-         (set! *funcs*
-               (cons (parse-func
-                      `(,(car field)
-                        (,(car (cddr field))
-                         #f
-                         ,(type-getter-name type name field))
-                        (,name)))
-                     *funcs*))))
-       (cond
-        ((and (pair? (cddr field))
-              (pair? (cdr (cddr field)))
-              (cadr (cddr field)))
-         (write-type-setter type name field)
-         (set! *funcs*
-               (cons (parse-func
-                      `(,(car field)
-                        (,(cadr (cddr field))
-                         #f
-                         ,(type-setter-name type name field))
-                        (,name ,(car field))))
-                     *funcs*)))))))
-   (struct-fields type)))
+  (let lp ((ls (struct-fields type))
+           (i 0))
+    (cond
+     ((not (pair? ls)))
+     ((and (pair? (car ls)) (pair? (cdar ls)))
+      (let* ((field (car ls))
+             (get+set (cddr field)))
+        (cond
+         ((and (pair? get+set) (car get+set))
+          (write-type-getter type name field)
+          (set! *funcs*
+                (cons (parse-func
+                       `(,(car field)
+                         (,(car get+set)
+                          #f
+                          ,(type-getter-name type name field))
+                         (,name)))
+                      *funcs*))
+          (if (type-struct-type name)
+              (set! *type-getters*
+                    (cons `(,(car get+set) ,name ,i) *type-getters*))))
+         (else "SEXP_FALSE"))
+        (cond
+         ((and (pair? get+set)
+               (pair? (cdr get+set))
+               (cadr get+set))
+          (write-type-setter type name field)
+          (set! *funcs*
+                (cons (parse-func
+                       `(,(car field)
+                         (,(cadr get+set)
+                          #f
+                          ,(type-setter-name type name field))
+                         (,name ,(car field))))
+                      *funcs*))
+          (if (type-struct-type name)
+              (set! *type-setters*
+                    (cons `(,(cadr get+set) ,name ,i) *type-setters*))))))
+      (lp (cdr ls) (+ i 1))))))
 
 (define (write-type-funcs orig-type)
   (let* ((name (car orig-type))