diff --git a/Makefile b/Makefile
index d57c5050..f82352da 100644
--- a/Makefile
+++ b/Makefile
@@ -29,7 +29,7 @@ BINDIR=$(PREFIX)/bin
 # TODO - when api is finalized, only export public symbols instead of using rdynamic
 # which exports all symbols.
 
-CFLAGS=-std=c99 -Wall -Wextra -Isrc/include -rdynamic -s -O3
+CFLAGS=-std=c99 -Wall -Wextra -Isrc/include -rdynamic -s -O2
 CLIBS=-lm -ldl
 PREFIX=/usr/local
 DST_TARGET=dst
diff --git a/src/core/array.c b/src/core/array.c
index f8afeabc..f5afef6e 100644
--- a/src/core/array.c
+++ b/src/core/array.c
@@ -23,7 +23,7 @@
 #include <dst/dst.h>
 #include "gc.h"
 
-/* Iniializes an array */
+/* Initializes an array */
 DstArray *dst_array_init(DstArray *array, int32_t capacity) {
     Dst *data = NULL;
     if (capacity > 0) {
@@ -67,7 +67,7 @@ void dst_array_setcount(DstArray *array, int32_t count) {
         return;
     if (count > array->count) {
         int32_t i;
-        dst_array_ensure(array, count + 1);
+        dst_array_ensure(array, count);
         for (i = array->count; i < count; i++) {
             array->data[i] = dst_wrap_nil();
         }
diff --git a/src/core/buffer.c b/src/core/buffer.c
index b287ab76..7329b61e 100644
--- a/src/core/buffer.c
+++ b/src/core/buffer.c
@@ -62,6 +62,18 @@ void dst_buffer_ensure(DstBuffer *buffer, int32_t capacity) {
     buffer->capacity = capacity;
 }
 
+/* Ensure that the buffer has enough internal capacity */
+void dst_buffer_setcount(DstBuffer *buffer, int32_t count) {
+    if (count < 0)
+        return;
+    if (count > buffer->count) {
+        int32_t oldcount = buffer->count;
+        dst_buffer_ensure(buffer, count);
+        memset(buffer->data + oldcount, 0, count - oldcount);
+    }
+    buffer->count = count;
+}
+
 /* Adds capacity for enough extra bytes to the buffer. Ensures that the
  * next n bytes pushed to the buffer will not cause a reallocation */
 int dst_buffer_extra(DstBuffer *buffer, int32_t n) {
@@ -148,11 +160,13 @@ int dst_buffer_push_u64(DstBuffer *buffer, uint64_t x) {
 static int cfun_u8(DstArgs args) {
     int32_t i;
     DstBuffer *buffer;
-    if (args.n < 1 || !dst_checktype(args.v[0], DST_BUFFER)) return dst_throw(args, "expected buffer");
-    buffer = dst_unwrap_buffer(args.v[0]);
+    dst_minarity(args, 1);
+    dst_arg_buffer(buffer, args, 0);
     for (i = 1; i < args.n; i++) {
-        if (!dst_checktype(args.v[i], DST_INTEGER)) return dst_throw(args, "expected integer");
-        if (dst_buffer_push_u8(buffer, (uint8_t) (dst_unwrap_integer(args.v[i]) & 0xFF))) return dst_throw(args, "buffer overflow");
+        int32_t integer;
+        dst_arg_integer(integer, args, i);
+        if (dst_buffer_push_u8(buffer, (uint8_t) (integer & 0xFF)))
+            return dst_throw(args, "buffer overflow");
     }
     return dst_return(args, args.v[0]);
 }
@@ -160,11 +174,13 @@ static int cfun_u8(DstArgs args) {
 static int cfun_int(DstArgs args) {
     int32_t i;
     DstBuffer *buffer;
-    if (args.n < 1 || !dst_checktype(args.v[0], DST_BUFFER)) return dst_throw(args, "expected buffer");
-    buffer = dst_unwrap_buffer(args.v[0]);
+    dst_minarity(args, 1);
+    dst_arg_buffer(buffer, args, 0);
     for (i = 1; i < args.n; i++) {
-        if (!dst_checktype(args.v[i], DST_INTEGER)) return dst_throw(args, "expected integer");
-        if (dst_buffer_push_u32(buffer, (uint32_t) dst_unwrap_integer(args.v[i]))) return dst_throw(args, "buffer overflow");
+        int32_t integer;
+        dst_arg_integer(integer, args, i);
+        if (dst_buffer_push_u32(buffer, (uint32_t) integer)) 
+            return dst_throw(args, "buffer overflow");
     }
     return dst_return(args, args.v[0]);
 }
@@ -172,38 +188,37 @@ static int cfun_int(DstArgs args) {
 static int cfun_chars(DstArgs args) {
     int32_t i;
     DstBuffer *buffer;
-    if (args.n < 1 || !dst_checktype(args.v[0], DST_BUFFER)) return dst_throw(args, "expected buffer");
-    buffer = dst_unwrap_buffer(args.v[0]);
+    dst_minarity(args, 1);
+    dst_arg_buffer(buffer, args, 0);
     for (i = 1; i < args.n; i++) {
         int32_t len;
         const uint8_t *str;
-        if (!dst_chararray_view(args.v[i], &str, &len)) return dst_throw(args, "expected string/buffer");
-        if (dst_buffer_push_bytes(buffer, str, len)) return dst_throw(args, "buffer overflow");
+        if (!dst_chararray_view(args.v[i], &str, &len)) 
+            return dst_throw(args, "expected string|symbol|buffer");
+        if (dst_buffer_push_bytes(buffer, str, len)) 
+            return dst_throw(args, "buffer overflow");
     }
     return dst_return(args, args.v[0]);
 }
 
 static int cfun_clear(DstArgs args) {
     DstBuffer *buffer;
-    if (args.n < 1 || !dst_checktype(args.v[0], DST_BUFFER)) return dst_throw(args, "expected buffer");
-    buffer = dst_unwrap_buffer(args.v[0]);
+    dst_fixarity(args, 1);
+    dst_arg_buffer(buffer, args, 0);
     buffer->count = 0;
     return dst_return(args, args.v[0]);
 }
 
 static int cfun_popn(DstArgs args) {
     DstBuffer *buffer;
-    int32_t i;
-    if (args.n < 2
-            || !dst_checktype(args.v[0], DST_BUFFER)
-            || !dst_checktype(args.v[1], DST_INTEGER)) return dst_throw(args, "expected buffer and integer");
-    buffer = dst_unwrap_buffer(args.v[0]);
-    i = dst_unwrap_integer(args.v[1]);
-    if (i < 0) return dst_throw(args, "expected positive integer");
-    if (buffer->count < i) {
+    int32_t n;
+    dst_fixarity(args, 2);
+    dst_arg_buffer(buffer, args, 0);
+    dst_arg_integer(n, args, 1);
+    if (buffer->count < n) {
         buffer->count = 0;
     } else {
-        buffer->count -= i;
+        buffer->count -= n;
     }
     return dst_return(args, args.v[0]);
 }
diff --git a/src/core/fiber.c b/src/core/fiber.c
index bab9262f..9279d51e 100644
--- a/src/core/fiber.c
+++ b/src/core/fiber.c
@@ -259,17 +259,16 @@ void dst_fiber_popframe(DstFiber *fiber) {
 
 static int cfun_fiber(DstArgs args) {
     DstFiber *fiber;
-    if (args.n < 1) return dst_throw(args, "expected at least 1 argument");
-    if (!dst_checktype(args.v[0], DST_FUNCTION))
-        return dst_throw(args, "expected a function");
+    dst_fixarity(args, 1);
+    dst_check(args, 0, DST_FUNCTION);
     fiber = dst_fiber(dst_unwrap_function(args.v[0]), 64);
     return dst_return(args, dst_wrap_fiber(fiber));
 }
 
 static int cfun_status(DstArgs args) {
     const char *status = "";
-    if (args.n != 1) return dst_throw(args, "expected 1 argument");
-    if (!dst_checktype(args.v[0], DST_FIBER)) return dst_throw(args, "expected fiber");
+    dst_fixarity(args, 1);
+    dst_check(args, 0, DST_FIBER);
     switch(dst_unwrap_fiber(args.v[0])->status) {
         case DST_FIBER_PENDING:
             status = ":pending";
@@ -330,8 +329,8 @@ static Dst doframe(DstStackFrame *frame) {
 static int cfun_stack(DstArgs args) {
     DstFiber *fiber;
     DstArray *array;
-    if (args.n != 1) return dst_throw(args, "expected 1 argument");
-    if (!dst_checktype(args.v[0], DST_FIBER)) return dst_throw(args, "expected fiber");
+    dst_fixarity(args, 1);
+    dst_check(args, 0, DST_FIBER);
     fiber = dst_unwrap_fiber(args.v[0]);
     array = dst_array(0);
     {
diff --git a/src/core/io.c b/src/core/io.c
index 91020273..b21961c5 100644
--- a/src/core/io.c
+++ b/src/core/io.c
@@ -84,16 +84,16 @@ static int checkflags(const uint8_t *str, int32_t len) {
 static IOFile *checkfile(DstArgs args, int32_t n) {
     IOFile *iof;
     if (n >= args.n) {
-	*args.ret = dst_cstringv("expected core.file");
+        *args.ret = dst_cstringv("expected core.file");
         return NULL;
     }
     if (!dst_checktype(args.v[n], DST_ABSTRACT)) {
-	*args.ret = dst_cstringv("expected core.file");
+        *args.ret = dst_cstringv("expected core.file");
         return NULL;
     }
     iof = (IOFile *) dst_unwrap_abstract(args.v[n]);
     if (dst_abstract_type(iof) != &dst_io_filetype) {
-	*args.ret = dst_cstringv("expected core.file");
+        *args.ret = dst_cstringv("expected core.file");
         return NULL;
     }
     return iof;
@@ -105,11 +105,11 @@ static DstBuffer *checkbuffer(DstArgs args, int32_t n, int optional) {
         return dst_buffer(0);
     }
     if (n >= args.n) {
-	*args.ret = dst_cstringv("expected buffer");
+        *args.ret = dst_cstringv("expected buffer");
         return NULL;
     }
     if (!dst_checktype(args.v[n], DST_BUFFER)) {
-	*args.ret = dst_cstringv("expected buffer");
+        *args.ret = dst_cstringv("expected buffer");
         return NULL;
     }
     return dst_unwrap_abstract(args.v[n]);
@@ -141,8 +141,9 @@ static int dst_io_fopen(DstArgs args) {
     int32_t modelen;
     FILE *f;
     int flags;
-    if (args.n < 1 || args.n > 2) return dst_throw(args, "expected 1 or 2 arguments");
-    if (!dst_checktype(args.v[0], DST_STRING)) return dst_throw(args, "expected string filename");
+    dst_minarity(args, 1);
+    dst_maxarity(args, 2);
+    dst_check(args, 0, DST_STRING);
     fname = dst_unwrap_string(args.v[0]);
     if (args.n == 2) {
         if (!dst_checktype(args.v[1], DST_STRING) &&
diff --git a/src/core/util.c b/src/core/util.c
index 7be8290b..cdd66d7e 100644
--- a/src/core/util.c
+++ b/src/core/util.c
@@ -206,13 +206,20 @@ int dst_hashtable_view(Dst tab, const DstKV **data, int32_t *len, int32_t *cap)
     return 0;
 }
 
-int dst_type_err(DstArgs args, int32_t n, DstType expected) {
+/* Get actual type name of a value for debugging purposes */
+static const char *typestr(DstArgs args, int32_t n) {
     DstType actual = n < args.n ? dst_type(args.v[n]) : DST_NIL;
+    return (actual == DST_ABSTRACT)
+        ? dst_abstract_type(dst_unwrap_abstract(args.v[n]))->name
+        : dst_type_names[actual];
+}
+
+int dst_type_err(DstArgs args, int32_t n, DstType expected) {
     const uint8_t *message = dst_formatc(
-            "bad argument #%d, expected %t, got %t",
+            "bad argument #%d, expected %t, got %s",
             n,
             expected,
-            actual);
+            typestr(args, n));
     return dst_throwv(args, dst_wrap_string(message));
 }
 
@@ -220,7 +227,6 @@ int dst_typemany_err(DstArgs args, int32_t n, int expected) {
     int i;
     int first = 1;
     const uint8_t *message;
-    DstType actual = n < args.n ? dst_type(args.v[n]) : DST_NIL;
     DstBuffer buf;
     dst_buffer_init(&buf, 20);
     dst_buffer_push_string(&buf, dst_formatc("bad argument #%d, expected ", n));
@@ -238,7 +244,7 @@ int dst_typemany_err(DstArgs args, int32_t n, int expected) {
         expected >>= 1;
     }
     dst_buffer_push_cstring(&buf, ", got ");
-    dst_buffer_push_cstring(&buf, dst_type_names[actual] + 1);
+    dst_buffer_push_cstring(&buf, typestr(args, n));
     message = dst_string(buf.data, buf.count);
     dst_buffer_deinit(&buf);
     return dst_throwv(args, dst_wrap_string(message));
@@ -250,3 +256,10 @@ int dst_arity_err(DstArgs args, int32_t n, const char *prefix) {
                     "expected %s%d argument%s, got %d", 
                     prefix, n, n == 1 ? "" : "s", args.n)));
 }
+
+int dst_typeabstract_err(DstArgs args, int32_t n, DstAbstractType *at) {
+    return dst_throwv(args,
+            dst_wrap_string(dst_formatc(
+                    "bad argument #%d, expected %t, got %s", 
+                    n, at->name, typestr(args, n)))); 
+}
diff --git a/src/core/value.c b/src/core/value.c
index d9a04134..6367c7f3 100644
--- a/src/core/value.c
+++ b/src/core/value.c
@@ -151,10 +151,8 @@ int dst_compare(Dst x, Dst y) {
                     return dst_unwrap_string(x) > dst_unwrap_string(y) ? 1 : -1;
                 }
         }
-    } else if (dst_type(x) < dst_type(y)) {
-        return -1;
-    }
-    return 1;
+    } 
+    return (dst_type(x) < dst_type(y)) ? -1 : 1;
 }
 
 /* Get a value out af an associated data structure. For invalid
@@ -200,19 +198,36 @@ Dst dst_get(Dst ds, Dst key) {
  * error message, and NULL if no error. */
 void dst_put(Dst ds, Dst key, Dst value) {
     switch (dst_type(ds)) {
-    case DST_ARRAY:
-        if (dst_checktype(key, DST_INTEGER) &&
-                dst_unwrap_integer(key) >= 0 &&
-                dst_unwrap_integer(key) < dst_unwrap_array(ds)->count)
-            dst_unwrap_array(ds)->data[dst_unwrap_integer(key)] = value;
+    case DST_ARRAY: 
+    {
+        int32_t index;
+        DstArray *array = dst_unwrap_array(ds);
+        if (!dst_checktype(key, DST_INTEGER) || dst_unwrap_integer(key) < 0)
+            return;
+        index = dst_unwrap_integer(key);
+        if (index == INT32_MAX) return;
+        if (index >= array->count) {
+            dst_array_setcount(array, index + 1);
+        }
+        array->data[index]= value;
         return;
+    }
     case DST_BUFFER:
-        if (dst_checktype(key, DST_INTEGER) &&
-                dst_checktype(value, DST_INTEGER) &&
-                dst_unwrap_integer(key) >= 0 &&
-                dst_unwrap_integer(key) < dst_unwrap_buffer(ds)->count)
-            dst_unwrap_buffer(ds)->data[dst_unwrap_integer(key)] = dst_unwrap_integer(value);
+    {
+        int32_t index;
+        DstBuffer *buffer = dst_unwrap_buffer(ds);
+        if (!dst_checktype(key, DST_INTEGER) || dst_unwrap_integer(key) < 0)
+            return;
+        index = dst_unwrap_integer(key);
+        if (index == INT32_MAX) return;
+        if (!dst_checktype(value, DST_INTEGER))
+            return;
+        if (index >= buffer->count) {
+            dst_buffer_setcount(buffer, index + 1);
+        }
+        buffer->data[index] = (uint8_t) (dst_unwrap_integer(value) & 0xFF);
         return;
+    }
     case DST_TABLE:
         dst_table_put(dst_unwrap_table(ds), key, value);
         return;
diff --git a/src/exported.list b/src/exported.list
deleted file mode 100644
index bd0591b6..00000000
--- a/src/exported.list
+++ /dev/null
@@ -1,240 +0,0 @@
-{
-dst_array;
-dst_array_init;
-dst_array_deinit;
-dst_array_ensure;
-dst_array_setcount;
-dst_array_push;
-dst_array_pop;
-dst_array_peek;
-
-dst_buffer;
-dst_buffer_init;
-dst_buffer_deinit;
-dst_buffer_ensure;
-dst_buffer_extra;
-dst_buffer_push_bytes;
-dst_buffer_push_cstring;
-dst_buffer_push_u8;
-dst_buffer_push_u16;
-dst_buffer_push_u32;
-dst_buffer_push_u64;
-
-dst_tuple_begin;
-dst_tuple_end;
-dst_tuple_n;
-dst_tuple_equal;
-dst_tuple_compare;
-
-dst_string_begin;
-dst_string_end;
-dst_string;
-dst_cstring;
-dst_string_compare;
-dst_string_equal;
-dst_string_equalconst;
-dst_string_unique;
-dst_cstring_unique;
-dst_description;
-dst_to_string;
-dst_to_zerostring;
-dst_formatc;
-dst_puts;
-
-dst_symbol;
-dst_symbol_from_string;
-dst_csymbol;
-dst_symbol_gen;
-
-dst_struct_begin;
-dst_struct_put;
-dst_struct_end;
-dst_struct_get;
-dst_struct_next;
-dst_struct_to_table;
-dst_struct_equal;
-dst_struct_compare;
-dst_struct_find;
-
-dst_table;
-dst_table_init;
-dst_table_deinit;
-dst_table_get;
-dst_table_rawget;
-dst_table_remove;
-dst_table_put;
-dst_table_next;
-dst_table_to_struct;
-dst_table_merge_table;
-dst_table_merge_struct;
-dst_table_find;
-
-dst_fiber;
-
-dst_seq_view;
-dst_chararray_view;
-dst_hashtable_view;
-
-dst_abstract;
-
-dst_native;
-
-dst_mark;
-dst_sweep;
-dst_collect;
-dst_clear_memory;
-dst_gcroot;
-dst_gcunroot;
-dst_gcunrootall;
-dst_gclock;
-dst_gcunlock;
-
-dst_funcdef_alloc;
-dst_thunk;
-dst_verify;
-dst_quick_asm;
-
-dst_equals;
-dst_hash;
-dst_compare;
-dst_get;
-dst_put;
-dst_next;
-dst_length;
-dst_getindex;
-dst_setindex;
-dst_cstrcmp;
-
-dst_init;
-dst_deinit;
-dst_run;
-dst_resume;
-
-dst_env_def;
-dst_env_var;
-dst_env_cfuns;
-dst_env_resolve;
-dst_env_arg;
-
-dst_stl_env;
-
-dst_asm;
-dst_disasm;
-dst_asm_decode_instruction;
-dst_asm_cfun;
-dst_disasm_cfun;
-
-dst_lib_asm;
-
-dst_compile;
-
-dst_compile_cfun;
-dst_lib_compile;
-
-dst_stl_env;
-
-dst_dobytes;
-dst_dostring;
-
-dst_core_native;
-
-dst_int;
-dst_real;
-dst_add;
-dst_subtract;
-dst_multiply;
-dst_divide;
-dst_modulo;
-dst_rand;
-dst_srand;
-dst_strict_equal;
-dst_strict_notequal;
-dst_ascending;
-dst_descending;
-dst_notdescending;
-dst_notascending;
-dst_numeric_eq;
-dst_numeric_neq;
-dst_numeric_gt;
-dst_numeric_lt;
-dst_numeric_gte;
-dst_numeric_lte;
-dst_bor;
-dst_band;
-dst_bxor;
-dst_bnot;
-dst_lshift;
-dst_rshift;
-dst_lshiftu;
-dst_not;
-
-dst_cos;
-dst_sin;
-dst_tan;
-dst_acos;
-dst_asin;
-dst_atan;
-dst_exp;
-dst_log;
-dst_log10;
-dst_sqrt;
-dst_floor;
-dst_ceil;
-dst_pow;
-
-dst_core_print;
-dst_core_describe;
-dst_core_string;
-dst_core_symbol;
-dst_core_buffer;
-dst_core_tuple;
-dst_core_array;
-dst_core_table;
-dst_core_struct;
-dst_core_buffer;
-dst_core_gensym;
-dst_core_length;
-dst_core_get;
-dst_core_rawget;
-dst_core_getproto;
-dst_core_setproto;
-dst_core_put;
-dst_core_type;
-dst_core_next;
-dst_core_hash;
-dst_core_string_slice;
-
-dst_core_gccollect;
-dst_core_gcsetinterval;
-dst_core_gcinterval;
-
-dst_lib_io;
-dst_lib_math;
-dst_lib_array;
-dst_lib_tuple;
-dst_lib_buffer;
-dst_lib_table;
-dst_lib_fiber;
-dst_lib_os;
-
-dst_ast_wrap;
-dst_ast_node;
-dst_ast_unwrap1;
-dst_ast_unwrap;
-
-dst_scan_number;
-dst_scan_integer;
-dst_scan_real;
-
-dst_parser_init;
-dst_parser_deinit;
-dst_parser_consume;
-dst_parser_status;
-dst_parser_produce;
-dst_parser_error;
-
-dst_parse_cfun;
-
-dst_lib_parse;
-
-};
diff --git a/src/include/dst/dst.h b/src/include/dst/dst.h
index 033c9947..1f937e6d 100644
--- a/src/include/dst/dst.h
+++ b/src/include/dst/dst.h
@@ -51,6 +51,7 @@ DstBuffer *dst_buffer(int32_t capacity);
 DstBuffer *dst_buffer_init(DstBuffer *buffer, int32_t capacity);
 void dst_buffer_deinit(DstBuffer *buffer);
 void dst_buffer_ensure(DstBuffer *buffer, int32_t capacity);
+void dst_buffer_setcount(DstBuffer *buffer, int32_t count);
 int dst_buffer_extra(DstBuffer *buffer, int32_t n);
 int dst_buffer_push_bytes(DstBuffer *buffer, const uint8_t *string, int32_t len);
 int dst_buffer_push_string(DstBuffer *buffer, const uint8_t *string);
@@ -195,9 +196,12 @@ DstTable *dst_stl_env(void);
 int dst_arity_err(DstArgs args, int32_t n, const char *prefix);
 int dst_type_err(DstArgs args, int32_t n, DstType expected);
 int dst_typemany_err(DstArgs args, int32_t n, int expected);
+int dst_typeabstract_err(DstArgs args, int32_t n, DstAbstractType *at);
 #define dst_throw(a, e) (*((a).ret) = dst_cstringv(e), 1)
 #define dst_throwv(a, v) (*((a).ret) = (v), 1)
 #define dst_return(a, v) (*((a).ret) = (v), 0)
+
+/* Early exit macros */
 #define dst_maxarity(A, N) do { if ((A).n > (N))\
     return dst_arity_err(A, N, "at most "); } while (0)
 #define dst_minarity(A, N) do { if ((A).n < (N))\
@@ -220,6 +224,53 @@ int dst_typemany_err(DstArgs args, int32_t n, int expected);
     }\
 } while (0)
 
+#define dst_checkabstract(A, N, AT) do {\
+    if ((A).n <= (N) || !dst_checktype() {\
+        Dst x = (A).v[(N)];\
+        if (!dst_checktype(x, DST_ABSTRACT) ||\
+                dst_abstract_type(dst_unwrap_abstract(x)) != (AT))\
+        return dst_typeabstract_err(A, N, AT);\
+    } else {\
+        return dst_typeabstract_err(A, N, AT);\
+    }\
+} while (0)
+
+#define dst_arg_abstract(DEST, A, N, AT) do {\
+    dst_checkabstract(A, N, AT);\
+    DEST = dst_unwrap_abstract((A).v[(N)]);\
+} while (0)
+
+#define dst_arg_integer(DEST, A, N) do { \
+    dst_check(A, N, DST_INTEGER);\
+    DEST = dst_unwrap_integer((A).v[(N)]); } while (0)
+
+#define dst_arg_real(DEST, A, N) do { \
+    dst_check(A, N, DST_REAL);\
+    DEST = dst_unwrap_real((A).v[(N)]); } while (0)
+
+#define dst_arg_number(DEST, A, N) do { \
+    if ((A).n <= (N)) return dst_typemany_err(A, N, DST_TFLAG_NUMBER);\
+    Dst val = (A).v[(N)];\
+    if (dst_checktype(val, DST_REAL)) { DEST = dst_unwrap_real(val); }\
+    else if (dst_checktype(val, DST_INTEGER)) { DEST = (double) dst_unwrap_integer(val); }\
+    else dst_typemany_err(A, N, DST_TFLAG_NUMBER); } while (0)
+
+#define dst_arg_boolean(DEST, A, N) do { \
+    dst_checkmany(A, N, DST_TFLAG_TRUE | DST_TFLAG_FALSE);\
+    DEST = dst_unwrap_boolean((A).v[(N)]); } while (0)
+
+#define dst_arg_string(DEST, A, N) do { \
+    dst_check(A, N, DST_STRING);\
+    DEST = dst_unwrap_string((A).v[(N)]); } while (0)
+
+#define dst_arg_symbol(DEST, A, N) do { \
+    dst_check(A, N, DST_SYMBOL);\
+    DEST = dst_unwrap_string((A).v[(N)]); } while (0)
+
+#define dst_arg_buffer(DEST, A, N) do { \
+    dst_check(A, N, DST_BUFFER);\
+    DEST = dst_unwrap_buffer((A).v[(N)]); } while (0)
+
 #ifdef __cplusplus
 }
 #endif