diff --git a/extlib/benz/boot.c b/extlib/benz/boot.c
index 6fb9bff3..8918625c 100644
--- a/extlib/benz/boot.c
+++ b/extlib/benz/boot.c
@@ -24,21 +24,22 @@ my $src = <<'EOL';
                 val))))))
 
   (define (er-macro-transformer f)
-    (lambda (expr use-env mac-env)
+    (lambda (mac-env)
+      (lambda (expr use-env)
 
-      (define rename
-        (memoize
-         (lambda (sym)
-           (make-identifier sym mac-env))))
+        (define rename
+          (memoize
+           (lambda (sym)
+             (make-identifier sym mac-env))))
 
-      (define (compare x y)
-        (if (not (symbol? x))
-            #f
-            (if (not (symbol? y))
-                #f
-                (identifier=? use-env x use-env y))))
+        (define (compare x y)
+          (if (not (symbol? x))
+              #f
+              (if (not (symbol? y))
+                  #f
+                  (identifier=? use-env x use-env y))))
 
-      (f expr rename compare)))
+        (f expr rename compare))))
 
   (define-syntax syntax-error
     (er-macro-transformer
@@ -50,7 +51,8 @@ my $src = <<'EOL';
      (lambda (expr r c)
        (list (r 'define-syntax) (cadr expr)
              (list (r 'lambda) '_
-                   (list (r 'error) "invalid use of auxiliary syntax"))))))
+                   (list (r 'lambda) '_
+                         (list (r 'error) "invalid use of auxiliary syntax")))))))
 
   (define-auxiliary-syntax else)
   (define-auxiliary-syntax =>)
@@ -422,21 +424,22 @@ const char pic_boot[] =
 "                val))))))\n"
 "\n"
 "  (define (er-macro-transformer f)\n"
-"    (lambda (expr use-env mac-env)\n"
+"    (lambda (mac-env)\n"
+"      (lambda (expr use-env)\n"
 "\n"
-"      (define rename\n"
-"        (memoize\n"
-"         (lambda (sym)\n"
-"           (make-identifier sym mac-env))))\n"
+"        (define rename\n"
+"          (memoize\n"
+"           (lambda (sym)\n"
+"             (make-identifier sym mac-env))))\n"
 "\n"
-"      (define (compare x y)\n"
-"        (if (not (symbol? x))\n"
-"            #f\n"
-"            (if (not (symbol? y))\n"
-"                #f\n"
-"                (identifier=? use-env x use-env y))))\n"
+"        (define (compare x y)\n"
+"          (if (not (symbol? x))\n"
+"              #f\n"
+"              (if (not (symbol? y))\n"
+"                  #f\n"
+"                  (identifier=? use-env x use-env y))))\n"
 "\n"
-"      (f expr rename compare)))\n"
+"        (f expr rename compare))))\n"
 "\n"
 "  (define-syntax syntax-error\n"
 "    (er-macro-transformer\n"
@@ -448,7 +451,8 @@ const char pic_boot[] =
 "     (lambda (expr r c)\n"
 "       (list (r 'define-syntax) (cadr expr)\n"
 "             (list (r 'lambda) '_\n"
-"                   (list (r 'error) \"invalid use of auxiliary syntax\"))))))\n"
+"                   (list (r 'lambda) '_\n"
+"                         (list (r 'error) \"invalid use of auxiliary syntax\")))))))\n"
 "\n"
 "  (define-auxiliary-syntax else)\n"
 "  (define-auxiliary-syntax =>)\n"
diff --git a/extlib/benz/gc.c b/extlib/benz/gc.c
index c09765fd..e209ddda 100644
--- a/extlib/benz/gc.c
+++ b/extlib/benz/gc.c
@@ -415,17 +415,6 @@ gc_mark_object(pic_state *pic, struct pic_object *obj)
   case PIC_TT_BLOB: {
     break;
   }
-  case PIC_TT_MACRO: {
-    struct pic_macro *mac = (struct pic_macro *)obj;
-
-    if (mac->proc) {
-      gc_mark_object(pic, (struct pic_object *)mac->proc);
-    }
-    if (mac->senv) {
-      gc_mark_object(pic, (struct pic_object *)mac->senv);
-    }
-    break;
-  }
   case PIC_TT_SENV: {
     struct pic_senv *senv = (struct pic_senv *)obj;
 
@@ -650,9 +639,6 @@ gc_finalize_object(pic_state *pic, struct pic_object *obj)
     xh_destroy(&senv->map);
     break;
   }
-  case PIC_TT_MACRO: {
-    break;
-  }
   case PIC_TT_LIB: {
     struct pic_lib *lib = (struct pic_lib *)obj;
     xh_destroy(&lib->exports);
diff --git a/extlib/benz/include/picrin/macro.h b/extlib/benz/include/picrin/macro.h
index 79148e51..fe4074f5 100644
--- a/extlib/benz/include/picrin/macro.h
+++ b/extlib/benz/include/picrin/macro.h
@@ -16,15 +16,6 @@ struct pic_senv {
   struct pic_senv *up;
 };
 
-struct pic_macro {
-  PIC_OBJECT_HEADER
-  struct pic_proc *proc;
-  struct pic_senv *senv;
-};
-
-#define pic_macro_p(v) (pic_type(v) == PIC_TT_MACRO)
-#define pic_macro_ptr(v) ((struct pic_macro *)pic_ptr(v))
-
 #define pic_senv_p(v) (pic_type(v) == PIC_TT_SENV)
 #define pic_senv_ptr(v) ((struct pic_senv *)pic_ptr(v))
 
diff --git a/extlib/benz/include/picrin/value.h b/extlib/benz/include/picrin/value.h
index d21a8418..493cb033 100644
--- a/extlib/benz/include/picrin/value.h
+++ b/extlib/benz/include/picrin/value.h
@@ -125,7 +125,6 @@ enum pic_tt {
   PIC_TT_ERROR,
   PIC_TT_ENV,
   PIC_TT_SENV,
-  PIC_TT_MACRO,
   PIC_TT_LIB,
   PIC_TT_IREP,
   PIC_TT_DATA,
@@ -266,8 +265,6 @@ pic_type_repr(enum pic_tt tt)
     return "proc";
   case PIC_TT_SENV:
     return "senv";
-  case PIC_TT_MACRO:
-    return "macro";
   case PIC_TT_LIB:
     return "lib";
   case PIC_TT_IREP:
diff --git a/extlib/benz/macro.c b/extlib/benz/macro.c
index eb811253..d5604635 100644
--- a/extlib/benz/macro.c
+++ b/extlib/benz/macro.c
@@ -47,18 +47,12 @@ pic_find_rename(pic_state *pic, struct pic_senv *senv, pic_sym sym, pic_sym *ren
 }
 
 static void
-define_macro(pic_state *pic, pic_sym rename, struct pic_proc *proc, struct pic_senv *senv)
+define_macro(pic_state *pic, pic_sym rename, struct pic_proc *mac)
 {
-  struct pic_macro *mac;
-
-  mac = (struct pic_macro *)pic_obj_alloc(pic, sizeof(struct pic_macro), PIC_TT_MACRO);
-  mac->senv = senv;
-  mac->proc = proc;
-
   xh_put_int(&pic->macros, rename, &mac);
 }
 
-static struct pic_macro *
+static struct pic_proc *
 find_macro(pic_state *pic, pic_sym rename)
 {
   xh_entry *e;
@@ -66,7 +60,7 @@ find_macro(pic_state *pic, pic_sym rename)
   if ((e = xh_get_int(&pic->macros, rename)) == NULL) {
     return NULL;
   }
-  return xh_val(e, struct pic_macro *);
+  return xh_val(e, struct pic_proc *);
 }
 
 static pic_sym
@@ -252,13 +246,19 @@ macroexpand_defsyntax(pic_state *pic, pic_value expr, struct pic_senv *senv)
     pic_errorf(pic, "macro definition \"~s\" evaluates to non-procedure object", var);
   }
 
-  define_macro(pic, rename, pic_proc_ptr(val), senv);
+  val = pic_apply1(pic, pic_proc_ptr(val), pic_obj_value(senv));
+
+  if (! pic_proc_p(val)) {
+    pic_errorf(pic, "macro definition \"~s\" evaluates to non-procedure object", var);
+  }
+
+  define_macro(pic, rename, pic_proc_ptr(val));
 
   return pic_none_value();
 }
 
 static pic_value
-macroexpand_macro(pic_state *pic, struct pic_macro *mac, pic_value expr, struct pic_senv *senv)
+macroexpand_macro(pic_state *pic, struct pic_proc *mac, pic_value expr, struct pic_senv *senv)
 {
   pic_value v, args;
 
@@ -268,14 +268,10 @@ macroexpand_macro(pic_state *pic, struct pic_macro *mac, pic_value expr, struct
   puts("");
 #endif
 
-  if (mac->senv == NULL) { /* legacy macro */
-    args = pic_cdr(pic, expr);
-  } else {
-    args = pic_list3(pic, expr, pic_obj_value(senv), pic_obj_value(mac->senv));
-  }
+  args = pic_list2(pic, expr, pic_obj_value(senv));
 
   pic_try {
-    v = pic_apply(pic, mac->proc, args);
+    v = pic_apply(pic, mac, args);
   } pic_catch {
     pic_errorf(pic, "macroexpand error while application: %s", pic_errmsg(pic));
   }
@@ -298,7 +294,7 @@ macroexpand_node(pic_state *pic, pic_value expr, struct pic_senv *senv)
   }
   case PIC_TT_PAIR: {
     pic_value car;
-    struct pic_macro *mac;
+    struct pic_proc *mac;
 
     if (! pic_list_p(expr)) {
       pic_errorf(pic, "cannot macroexpand improper list: ~s", expr);
@@ -424,13 +420,33 @@ pic_define_syntactic_keyword(pic_state *pic, struct pic_senv *senv, pic_sym sym,
   }
 }
 
+static pic_value
+defmacro_call(pic_state *pic)
+{
+  struct pic_proc *self = pic_get_proc(pic);
+  pic_value args, tmp, proc;
+
+  pic_get_args(pic, "oo", &args, &tmp);
+
+  proc = pic_attr_ref(pic, pic_obj_value(self), "@@transformer");
+
+  return pic_apply_trampoline(pic, pic_proc_ptr(proc), pic_cdr(pic, args));
+}
+
 void
 pic_defmacro(pic_state *pic, pic_sym name, pic_sym id, pic_func_t func)
 {
+  struct pic_proc *proc, *trans;
+
+  trans = pic_make_proc(pic, func, pic_symbol_name(pic, name));
+
   pic_put_rename(pic, pic->lib->env, name, id);
 
+  proc = pic_make_proc(pic, defmacro_call, "defmacro_call");
+  pic_attr_set(pic, pic_obj_value(proc), "@@transformer", pic_obj_value(trans));
+
   /* symbol registration */
-  define_macro(pic, id, pic_make_proc(pic, func, pic_symbol_name(pic, name)), NULL);
+  define_macro(pic, id, proc);
 
   /* auto export! */
   pic_export(pic, name);
diff --git a/piclib/picrin/macro.scm b/piclib/picrin/macro.scm
index 22bdf097..e0942dd3 100644
--- a/piclib/picrin/macro.scm
+++ b/piclib/picrin/macro.scm
@@ -47,65 +47,70 @@
     (make-syntactic-closure env '() form))
 
   (define-syntax capture-syntactic-environment
-    (lambda (form use-env mac-env)
-      (list (cadr form) (list (make-identifier 'quote mac-env) mac-env))))
+    (lambda (mac-env)
+      (lambda (form use-env)
+        (list (cadr form) (list (make-identifier 'quote mac-env) mac-env)))))
 
   (define (sc-macro-transformer f)
-    (lambda (expr use-env mac-env)
-      (make-syntactic-closure mac-env '() (f expr use-env))))
+    (lambda (mac-env)
+      (lambda (expr use-env)
+        (make-syntactic-closure mac-env '() (f expr use-env)))))
 
   (define (rsc-macro-transformer f)
-    (lambda (expr use-env mac-env)
-      (make-syntactic-closure use-env '() (f expr mac-env))))
+    (lambda (mac-env)
+      (lambda (expr use-env)
+        (make-syntactic-closure use-env '() (f expr mac-env)))))
 
   (define (er-macro-transformer f)
-    (lambda (expr use-env mac-env)
+    (lambda (mac-env)
+      (lambda (expr use-env)
 
-      (define rename
-        (memoize
-         (lambda (sym)
-           (make-identifier sym mac-env))))
+        (define rename
+          (memoize
+           (lambda (sym)
+             (make-identifier sym mac-env))))
 
-      (define (compare x y)
-        (if (not (symbol? x))
-            #f
-            (if (not (symbol? y))
-                #f
-                (identifier=? use-env x use-env y))))
+        (define (compare x y)
+          (if (not (symbol? x))
+              #f
+              (if (not (symbol? y))
+                  #f
+                  (identifier=? use-env x use-env y))))
 
-      (f expr rename compare)))
+        (f expr rename compare))))
 
   (define (ir-macro-transformer f)
-    (lambda (expr use-env mac-env)
+    (lambda (mac-env)
+      (lambda (expr use-env)
 
-      (define icache* (make-dictionary))
+        (define icache* (make-dictionary))
 
-      (define inject
-        (memoize
-         (lambda (sym)
-           (define id (make-identifier sym use-env))
-           (dictionary-set! icache* id sym)
-           id)))
+        (define inject
+          (memoize
+           (lambda (sym)
+             (define id (make-identifier sym use-env))
+             (dictionary-set! icache* id sym)
+             id)))
 
-      (define rename
-        (memoize
-         (lambda (sym)
-           (make-identifier sym mac-env))))
+        (define rename
+          (memoize
+           (lambda (sym)
+             (make-identifier sym mac-env))))
 
-      (define (compare x y)
-        (if (not (symbol? x))
-            #f
-            (if (not (symbol? y))
-                #f
-                (identifier=? mac-env x mac-env y))))
+        (define (compare x y)
+          (if (not (symbol? x))
+              #f
+              (if (not (symbol? y))
+                  #f
+                  (identifier=? mac-env x mac-env y))))
 
-      (walk (lambda (sym)
-              (call-with-values (lambda () (dictionary-ref icache* sym))
-                (lambda (value exists)
-                  (if exists
-                      value
-                      (rename sym)))))
-            (f (walk inject expr) inject compare))))
+        (walk (lambda (sym)
+                (call-with-values (lambda () (dictionary-ref icache* sym))
+                  (lambda (value exists)
+                    (if exists
+                        value
+                        (rename sym)))))
+              (f (walk inject expr) inject compare)))))
 
   ;; (define (strip-syntax form)
   ;;   (walk ungensym form))
diff --git a/piclib/picrin/syntax-rules.scm b/piclib/picrin/syntax-rules.scm
index 342650a5..8b444085 100644
--- a/piclib/picrin/syntax-rules.scm
+++ b/piclib/picrin/syntax-rules.scm
@@ -7,7 +7,8 @@
      (lambda (expr r c)
        (list (r 'define-syntax) (cadr expr)
              (list (r 'lambda) '_
-                   (list (r 'error) "invalid use of auxiliary syntax"))))))
+                   (list (r 'lambda) '_
+                         (list (r 'error) "invalid use of auxiliary syntax")))))))
 
   (define-auxiliary-syntax _)
   (define-auxiliary-syntax ...)