diff --git a/extlib/benz/codegen.c b/extlib/benz/codegen.c
index 0e89c4b1..fa3125a7 100644
--- a/extlib/benz/codegen.c
+++ b/extlib/benz/codegen.c
@@ -36,11 +36,11 @@ typedef struct analyze_scope {
 typedef struct analyze_state {
   pic_state *pic;
   analyze_scope *scope;
-  pic_sym rCONS, rCAR, rCDR, rNILP;
-  pic_sym rSYMBOLP, rPAIRP;
-  pic_sym rADD, rSUB, rMUL, rDIV;
-  pic_sym rEQ, rLT, rLE, rGT, rGE, rNOT;
-  pic_sym rVALUES, rCALL_WITH_VALUES;
+  pic_sym *rCONS, *rCAR, *rCDR, *rNILP;
+  pic_sym *rSYMBOLP, *rPAIRP;
+  pic_sym *rADD, *rSUB, *rMUL, *rDIV;
+  pic_sym *rEQ, *rLT, *rLE, *rGT, *rGE, *rNOT;
+  pic_sym *rVALUES, *rCALL_WITH_VALUES;
 } analyze_state;
 
 static bool push_scope(analyze_state *, pic_value);
@@ -51,7 +51,7 @@ static void pop_scope(analyze_state *);
   } while (0)
 
 #define register_renamed_symbol(pic, state, slot, lib, id) do {         \
-    pic_sym sym, gsym;                                                  \
+    pic_sym *sym, *gsym;                                                  \
     sym = pic_intern_cstr(pic, id);                                     \
     if (! pic_find_rename(pic, lib->env, sym, &gsym)) {                 \
       pic_errorf(pic, "internal error! native VM procedure not found: %s", id); \
@@ -63,7 +63,7 @@ static analyze_state *
 new_analyze_state(pic_state *pic)
 {
   analyze_state *state;
-  pic_sym sym;
+  pic_sym *sym;
 
   state = pic_alloc(pic, sizeof(analyze_state));
   state->pic = pic;
@@ -110,7 +110,7 @@ static bool
 analyze_args(pic_state *pic, pic_value formals, bool *varg, xvect *args, xvect *locals)
 {
   pic_value v, t;
-  pic_sym sym;
+  pic_sym *sym;
 
   for (v = formals; pic_pair_p(v); v = pic_cdr(pic, v)) {
     t = pic_car(pic, v);
@@ -143,9 +143,9 @@ push_scope(analyze_state *state, pic_value formals)
   bool varg;
   xvect args, locals, captures;
 
-  xv_init(&args, sizeof(pic_sym));
-  xv_init(&locals, sizeof(pic_sym));
-  xv_init(&captures, sizeof(pic_sym));
+  xv_init(&args, sizeof(pic_sym *));
+  xv_init(&locals, sizeof(pic_sym *));
+  xv_init(&captures, sizeof(pic_sym *));
 
   if (analyze_args(pic, formals, &varg, &args, &locals)) {
     scope = pic_alloc(pic, sizeof(analyze_scope));
@@ -184,9 +184,9 @@ pop_scope(analyze_state *state)
 }
 
 static bool
-lookup_scope(analyze_scope *scope, pic_sym sym)
+lookup_scope(analyze_scope *scope, pic_sym *sym)
 {
-  pic_sym *arg, *local;
+  pic_sym **arg, **local;
   size_t i;
 
   /* args */
@@ -205,9 +205,9 @@ lookup_scope(analyze_scope *scope, pic_sym sym)
 }
 
 static void
-capture_var(analyze_scope *scope, pic_sym sym)
+capture_var(analyze_scope *scope, pic_sym *sym)
 {
-  pic_sym *var;
+  pic_sym **var;
   size_t i;
 
   for (i = 0; i < xv_size(&scope->captures); ++i) {
@@ -222,7 +222,7 @@ capture_var(analyze_scope *scope, pic_sym sym)
 }
 
 static int
-find_var(analyze_state *state, pic_sym sym)
+find_var(analyze_state *state, pic_sym *sym)
 {
   analyze_scope *scope = state->scope;
   int depth = 0;
@@ -241,7 +241,7 @@ find_var(analyze_state *state, pic_sym sym)
 }
 
 static void
-define_var(analyze_state *state, pic_sym sym)
+define_var(analyze_state *state, pic_sym *sym)
 {
   pic_state *pic = state->pic;
   analyze_scope *scope = state->scope;
@@ -263,7 +263,7 @@ analyze(analyze_state *state, pic_value obj, bool tailpos)
   pic_state *pic = state->pic;
   size_t ai = pic_gc_arena_preserve(pic);
   pic_value res;
-  pic_sym tag;
+  pic_sym *tag;
 
   res = analyze_node(state, obj, tailpos);
 
@@ -284,7 +284,7 @@ analyze(analyze_state *state, pic_value obj, bool tailpos)
 }
 
 static pic_value
-analyze_global_var(analyze_state *state, pic_sym sym)
+analyze_global_var(analyze_state *state, pic_sym *sym)
 {
   pic_state *pic = state->pic;
 
@@ -292,7 +292,7 @@ analyze_global_var(analyze_state *state, pic_sym sym)
 }
 
 static pic_value
-analyze_local_var(analyze_state *state, pic_sym sym)
+analyze_local_var(analyze_state *state, pic_sym *sym)
 {
   pic_state *pic = state->pic;
 
@@ -300,7 +300,7 @@ analyze_local_var(analyze_state *state, pic_sym sym)
 }
 
 static pic_value
-analyze_free_var(analyze_state *state, pic_sym sym, int depth)
+analyze_free_var(analyze_state *state, pic_sym *sym, int depth)
 {
   pic_state *pic = state->pic;
 
@@ -308,7 +308,7 @@ analyze_free_var(analyze_state *state, pic_sym sym, int depth)
 }
 
 static pic_value
-analyze_var(analyze_state *state, pic_sym sym)
+analyze_var(analyze_state *state, pic_sym *sym)
 {
   pic_state *pic = state->pic;
   int depth;
@@ -330,7 +330,7 @@ static pic_value
 analyze_defer(analyze_state *state, pic_value name, pic_value formal, pic_value body)
 {
   pic_state *pic = state->pic;
-  const pic_sym sNOWHERE = pic_intern_cstr(pic, "<<nowhere>>");
+  pic_sym *sNOWHERE = pic_intern_cstr(pic, "<<nowhere>>");
   pic_value skel;
 
   skel = pic_list2(pic, pic_obj_value(pic->sGREF), pic_obj_value(sNOWHERE));
@@ -372,7 +372,7 @@ analyze_procedure(analyze_state *state, pic_value name, pic_value formals, pic_v
 
   if (push_scope(state, formals)) {
     analyze_scope *scope = state->scope;
-    pic_sym *var;
+    pic_sym **var;
     size_t i;
 
     args = pic_nil_value();
@@ -428,7 +428,7 @@ analyze_lambda(analyze_state *state, pic_value obj)
 }
 
 static pic_value
-analyze_declare(analyze_state *state, pic_sym var)
+analyze_declare(analyze_state *state, pic_sym *var)
 {
   define_var(state, var);
 
@@ -440,7 +440,7 @@ analyze_define(analyze_state *state, pic_value obj)
 {
   pic_state *pic = state->pic;
   pic_value var, val;
-  pic_sym sym;
+  pic_sym *sym;
 
   if (pic_length(pic, obj) != 3) {
     pic_errorf(pic, "syntax error");
@@ -652,7 +652,7 @@ analyze_call(analyze_state *state, pic_value obj, bool tailpos)
 {
   pic_state *pic = state->pic;
   pic_value seq, elt;
-  pic_sym call;
+  pic_sym *call;
 
   if (! tailpos) {
     call = pic->sCALL;
@@ -688,7 +688,7 @@ analyze_call_with_values(analyze_state *state, pic_value obj, bool tailpos)
 {
   pic_state *pic = state->pic;
   pic_value prod, cnsm;
-  pic_sym call;
+  pic_sym *call;
 
   if (pic_length(pic, obj) != 3) {
     pic_errorf(pic, "wrong number of arguments");
@@ -745,7 +745,7 @@ analyze_node(analyze_state *state, pic_value obj, bool tailpos)
 
     proc = pic_list_ref(pic, obj, 0);
     if (pic_sym_p(proc)) {
-      pic_sym sym = pic_sym_ptr(proc);
+      pic_sym *sym = pic_sym_ptr(proc);
 
       if (sym == pic->rDEFINE) {
         return analyze_define(state, obj);
@@ -861,7 +861,7 @@ pic_analyze(pic_state *pic, pic_value obj)
  */
 
 typedef struct codegen_context {
-  pic_sym name;
+  pic_sym *name;
   /* rest args variable is counted as a local */
   bool varg;
   xvect args, locals, captures;
@@ -875,7 +875,7 @@ typedef struct codegen_context {
   pic_value *pool;
   size_t plen, pcapa;
   /* symbol pool */
-  pic_sym *syms;
+  pic_sym **syms;
   size_t slen, scapa;
 
   struct codegen_context *up;
@@ -924,7 +924,7 @@ create_activation(codegen_context *cxt)
 {
   size_t i, n;
   xhash regs;
-  pic_sym *var;
+  pic_sym **var;
   size_t offset;
 
   xh_init_ptr(&regs, sizeof(size_t));
@@ -965,7 +965,7 @@ push_codegen_context(codegen_state *state, pic_value name, pic_value args, pic_v
   pic_state *pic = state->pic;
   codegen_context *cxt;
   pic_value var;
-  pic_sym sym;
+  pic_sym *sym;
 
   assert(pic_sym_p(name) || pic_false_p(name));
 
@@ -976,9 +976,9 @@ push_codegen_context(codegen_state *state, pic_value name, pic_value args, pic_v
     : pic_sym_ptr(name);
   cxt->varg = varg;
 
-  xv_init(&cxt->args, sizeof(pic_sym));
-  xv_init(&cxt->locals, sizeof(pic_sym));
-  xv_init(&cxt->captures, sizeof(pic_sym));
+  xv_init(&cxt->args, sizeof(pic_sym *));
+  xv_init(&cxt->locals, sizeof(pic_sym *));
+  xv_init(&cxt->captures, sizeof(pic_sym *));
 
   pic_for_each (var, args) {
     sym = pic_sym_ptr(var);
@@ -1005,7 +1005,7 @@ push_codegen_context(codegen_state *state, pic_value name, pic_value args, pic_v
   cxt->plen = 0;
   cxt->pcapa = PIC_POOL_SIZE;
 
-  cxt->syms = pic_calloc(pic, PIC_POOL_SIZE, sizeof(pic_sym));
+  cxt->syms = pic_calloc(pic, PIC_POOL_SIZE, sizeof(pic_sym *));
   cxt->slen = 0;
   cxt->scapa = PIC_POOL_SIZE;
 
@@ -1034,7 +1034,7 @@ pop_codegen_context(codegen_state *state)
   irep->ilen = state->cxt->ilen;
   irep->pool = pic_realloc(pic, state->cxt->pool, sizeof(pic_value) * state->cxt->plen);
   irep->plen = state->cxt->plen;
-  irep->syms = pic_realloc(pic, state->cxt->syms, sizeof(pic_sym) * state->cxt->slen);
+  irep->syms = pic_realloc(pic, state->cxt->syms, sizeof(pic_sym *) * state->cxt->slen);
   irep->slen = state->cxt->slen;
 
   /* finalize */
@@ -1051,11 +1051,11 @@ pop_codegen_context(codegen_state *state)
 }
 
 static int
-index_capture(codegen_state *state, pic_sym sym, int depth)
+index_capture(codegen_state *state, pic_sym *sym, int depth)
 {
   codegen_context *cxt = state->cxt;
   size_t i;
-  pic_sym *var;
+  pic_sym **var;
 
   while (depth-- > 0) {
     cxt = cxt->up;
@@ -1070,11 +1070,11 @@ index_capture(codegen_state *state, pic_sym sym, int depth)
 }
 
 static int
-index_local(codegen_state *state, pic_sym sym)
+index_local(codegen_state *state, pic_sym *sym)
 {
   codegen_context *cxt = state->cxt;
   size_t i, offset;
-  pic_sym *var;
+  pic_sym **var;
 
   offset = 1;
   for (i = 0; i < xv_size(&cxt->args); ++i) {
@@ -1092,7 +1092,7 @@ index_local(codegen_state *state, pic_sym sym)
 }
 
 static int
-index_symbol(codegen_state *state, pic_sym sym)
+index_symbol(codegen_state *state, pic_sym *sym)
 {
   pic_state *pic = state->pic;
   codegen_context *cxt = state->cxt;
@@ -1105,7 +1105,7 @@ index_symbol(codegen_state *state, pic_sym sym)
   }
   if (cxt->slen >= cxt->scapa) {
     cxt->scapa *= 2;
-    cxt->syms = pic_realloc(pic, cxt->syms, sizeof(pic_sym) * cxt->scapa);
+    cxt->syms = pic_realloc(pic, cxt->syms, sizeof(pic_sym *) * cxt->scapa);
   }
   cxt->syms[cxt->slen++] = sym;
   return i;
@@ -1118,7 +1118,7 @@ codegen(codegen_state *state, pic_value obj)
 {
   pic_state *pic = state->pic;
   codegen_context *cxt = state->cxt;
-  pic_sym sym;
+  pic_sym *sym;
 
   sym = pic_sym_ptr(pic_car(pic, obj));
   if (sym == pic->sGREF) {
@@ -1127,7 +1127,7 @@ codegen(codegen_state *state, pic_value obj)
     cxt->clen++;
     return;
   } else if (sym == pic->sCREF) {
-    pic_sym name;
+    pic_sym *name;
     int depth;
 
     depth = pic_int(pic_list_ref(pic, obj, 1));
@@ -1138,7 +1138,7 @@ codegen(codegen_state *state, pic_value obj)
     cxt->clen++;
     return;
   } else if (sym == pic->sLREF) {
-    pic_sym name;
+    pic_sym *name;
     int i;
 
     name = pic_sym_ptr(pic_list_ref(pic, obj, 1));
@@ -1154,7 +1154,7 @@ codegen(codegen_state *state, pic_value obj)
     return;
   } else if (sym == pic->sSETBANG) {
     pic_value var, val;
-    pic_sym type;
+    pic_sym *type;
 
     val = pic_list_ref(pic, obj, 2);
     codegen(state, val);
@@ -1170,7 +1170,7 @@ codegen(codegen_state *state, pic_value obj)
       return;
     }
     else if (type == pic->sCREF) {
-      pic_sym name;
+      pic_sym *name;
       int depth;
 
       depth = pic_int(pic_list_ref(pic, var, 1));
@@ -1184,7 +1184,7 @@ codegen(codegen_state *state, pic_value obj)
       return;
     }
     else if (type == pic->sLREF) {
-      pic_sym name;
+      pic_sym *name;
       int i;
 
       name = pic_sym_ptr(pic_list_ref(pic, var, 1));
diff --git a/extlib/benz/dict.c b/extlib/benz/dict.c
index 1e1331e6..d677e935 100644
--- a/extlib/benz/dict.c
+++ b/extlib/benz/dict.c
@@ -21,7 +21,7 @@ pic_make_dict(pic_state *pic)
 }
 
 pic_value
-pic_dict_ref(pic_state *pic, struct pic_dict *dict, pic_sym key)
+pic_dict_ref(pic_state *pic, struct pic_dict *dict, pic_sym *key)
 {
   xh_entry *e;
 
@@ -33,7 +33,7 @@ pic_dict_ref(pic_state *pic, struct pic_dict *dict, pic_sym key)
 }
 
 void
-pic_dict_set(pic_state *pic, struct pic_dict *dict, pic_sym key, pic_value val)
+pic_dict_set(pic_state *pic, struct pic_dict *dict, pic_sym *key, pic_value val)
 {
   PIC_UNUSED(pic);
 
@@ -49,7 +49,7 @@ pic_dict_size(pic_state *pic, struct pic_dict *dict)
 }
 
 bool
-pic_dict_has(pic_state *pic, struct pic_dict *dict, pic_sym key)
+pic_dict_has(pic_state *pic, struct pic_dict *dict, pic_sym *key)
 {
   PIC_UNUSED(pic);
 
@@ -57,7 +57,7 @@ pic_dict_has(pic_state *pic, struct pic_dict *dict, pic_sym key)
 }
 
 void
-pic_dict_del(pic_state *pic, struct pic_dict *dict, pic_sym key)
+pic_dict_del(pic_state *pic, struct pic_dict *dict, pic_sym *key)
 {
   if (xh_get_ptr(&dict->hash, key) == NULL) {
     pic_errorf(pic, "no slot named ~s found in dictionary", pic_obj_value(key));
@@ -111,7 +111,7 @@ static pic_value
 pic_dict_dictionary_ref(pic_state *pic)
 {
   struct pic_dict *dict;
-  pic_sym key;
+  pic_sym *key;
 
   pic_get_args(pic, "dm", &dict, &key);
 
@@ -126,7 +126,7 @@ static pic_value
 pic_dict_dictionary_set(pic_state *pic)
 {
   struct pic_dict *dict;
-  pic_sym key;
+  pic_sym *key;
   pic_value val;
 
   pic_get_args(pic, "dmo", &dict, &key, &val);
@@ -140,7 +140,7 @@ static pic_value
 pic_dict_dictionary_del(pic_state *pic)
 {
   struct pic_dict *dict;
-  pic_sym key;
+  pic_sym *key;
 
   pic_get_args(pic, "dm", &dict, &key);
 
@@ -187,7 +187,7 @@ pic_dict_dictionary_map(pic_state *pic)
         if (it[i] == NULL) {
           break;
         }
-        pic_push(pic, pic_obj_value(xh_key(it[i], pic_sym)), arg);
+        pic_push(pic, pic_obj_value(xh_key(it[i], pic_sym *)), arg);
         it[i] = xh_next(it[i]);
       }
       if (i != argc) {
@@ -233,7 +233,7 @@ pic_dict_dictionary_for_each(pic_state *pic)
         if (it[i] == NULL) {
           break;
         }
-        pic_push(pic, pic_obj_value(xh_key(it[i], pic_sym)), arg);
+        pic_push(pic, pic_obj_value(xh_key(it[i], pic_sym *)), arg);
         it[i] = xh_next(it[i]);
       }
       if (i != argc) {
@@ -262,7 +262,7 @@ pic_dict_dictionary_to_alist(pic_state *pic)
   pic_get_args(pic, "d", &dict);
 
   for (it = xh_begin(&dict->hash); it != NULL; it = xh_next(it)) {
-    item = pic_cons(pic, pic_obj_value(xh_key(it, pic_sym)), xh_val(it, pic_value));
+    item = pic_cons(pic, pic_obj_value(xh_key(it, pic_sym *)), xh_val(it, pic_value));
     pic_push(pic, item, alist);
   }
 
@@ -297,7 +297,7 @@ pic_dict_dictionary_to_plist(pic_state *pic)
   pic_get_args(pic, "d", &dict);
 
   for (it = xh_begin(&dict->hash); it != NULL; it = xh_next(it)) {
-    pic_push(pic, pic_obj_value(xh_key(it, pic_sym)), plist);
+    pic_push(pic, pic_obj_value(xh_key(it, pic_sym *)), plist);
     pic_push(pic, xh_val(it, pic_value), plist);
   }
 
diff --git a/extlib/benz/error.c b/extlib/benz/error.c
index 9a1ccac7..5df91233 100644
--- a/extlib/benz/error.c
+++ b/extlib/benz/error.c
@@ -125,7 +125,7 @@ pic_pop_try(pic_state *pic)
 }
 
 struct pic_error *
-pic_make_error(pic_state *pic, pic_sym type, const char *msg, pic_value irrs)
+pic_make_error(pic_state *pic, pic_sym *type, const char *msg, pic_value irrs)
 {
   struct pic_error *e;
   pic_str *stack;
@@ -175,7 +175,7 @@ pic_raise(pic_state *pic, pic_value err)
 }
 
 void
-pic_throw(pic_state *pic, pic_sym type, const char *msg, pic_value irrs)
+pic_throw(pic_state *pic, pic_sym *type, const char *msg, pic_value irrs)
 {
   struct pic_error *e;
 
@@ -253,7 +253,7 @@ static pic_value
 pic_error_make_error_object(pic_state *pic)
 {
   struct pic_error *e;
-  pic_sym type;
+  pic_sym *type;
   pic_str *msg;
   size_t argc;
   pic_value *argv;
diff --git a/extlib/benz/gc.c b/extlib/benz/gc.c
index a59c5b4c..5c5ef412 100644
--- a/extlib/benz/gc.c
+++ b/extlib/benz/gc.c
@@ -470,7 +470,7 @@ gc_mark_object(pic_state *pic, struct pic_object *obj)
     xh_entry *it;
 
     for (it = xh_begin(&dict->hash); it != NULL; it = xh_next(it)) {
-      gc_mark_object(pic, (struct pic_object *)xh_key(it, pic_sym));
+      gc_mark_object(pic, (struct pic_object *)xh_key(it, pic_sym *));
       gc_mark(pic, xh_val(it, pic_value));
     }
     break;
@@ -578,7 +578,7 @@ gc_mark_phase(pic_state *pic)
 
   /* mark all interned symbols */
   for (it = xh_begin(&pic->syms); it != NULL; it = xh_next(it)) {
-    gc_mark_object(pic, (struct pic_object *)xh_val(it, pic_sym));
+    gc_mark_object(pic, (struct pic_object *)xh_val(it, pic_sym *));
   }
 
   /* global variables */
diff --git a/extlib/benz/include/picrin.h b/extlib/benz/include/picrin.h
index 9c2ef399..0c950425 100644
--- a/extlib/benz/include/picrin.h
+++ b/extlib/benz/include/picrin.h
@@ -89,25 +89,25 @@ typedef struct {
 
   struct pic_lib *lib;
 
-  pic_sym sDEFINE, sLAMBDA, sIF, sBEGIN, sQUOTE, sSETBANG;
-  pic_sym sQUASIQUOTE, sUNQUOTE, sUNQUOTE_SPLICING;
-  pic_sym sDEFINE_SYNTAX, sIMPORT, sEXPORT;
-  pic_sym sDEFINE_LIBRARY, sIN_LIBRARY;
-  pic_sym sCOND_EXPAND, sAND, sOR, sELSE, sLIBRARY;
-  pic_sym sONLY, sRENAME, sPREFIX, sEXCEPT;
-  pic_sym sCONS, sCAR, sCDR, sNILP;
-  pic_sym sSYMBOLP, sPAIRP;
-  pic_sym sADD, sSUB, sMUL, sDIV, sMINUS;
-  pic_sym sEQ, sLT, sLE, sGT, sGE, sNOT;
-  pic_sym sREAD, sFILE;
-  pic_sym sGREF, sCREF, sLREF;
-  pic_sym sCALL, sTAILCALL, sRETURN;
-  pic_sym sCALL_WITH_VALUES, sTAILCALL_WITH_VALUES;
+  pic_sym *sDEFINE, *sLAMBDA, *sIF, *sBEGIN, *sQUOTE, *sSETBANG;
+  pic_sym *sQUASIQUOTE, *sUNQUOTE, *sUNQUOTE_SPLICING;
+  pic_sym *sDEFINE_SYNTAX, *sIMPORT, *sEXPORT;
+  pic_sym *sDEFINE_LIBRARY, *sIN_LIBRARY;
+  pic_sym *sCOND_EXPAND, *sAND, *sOR, *sELSE, *sLIBRARY;
+  pic_sym *sONLY, *sRENAME, *sPREFIX, *sEXCEPT;
+  pic_sym *sCONS, *sCAR, *sCDR, *sNILP;
+  pic_sym *sSYMBOLP, *sPAIRP;
+  pic_sym *sADD, *sSUB, *sMUL, *sDIV, *sMINUS;
+  pic_sym *sEQ, *sLT, *sLE, *sGT, *sGE, *sNOT;
+  pic_sym *sREAD, *sFILE;
+  pic_sym *sGREF, *sCREF, *sLREF;
+  pic_sym *sCALL, *sTAILCALL, *sRETURN;
+  pic_sym *sCALL_WITH_VALUES, *sTAILCALL_WITH_VALUES;
 
-  pic_sym rDEFINE, rLAMBDA, rIF, rBEGIN, rQUOTE, rSETBANG;
-  pic_sym rDEFINE_SYNTAX, rIMPORT, rEXPORT;
-  pic_sym rDEFINE_LIBRARY, rIN_LIBRARY;
-  pic_sym rCOND_EXPAND;
+  pic_sym *rDEFINE, *rLAMBDA, *rIF, *rBEGIN, *rQUOTE, *rSETBANG;
+  pic_sym *rDEFINE_SYNTAX, *rIMPORT, *rEXPORT;
+  pic_sym *rDEFINE_LIBRARY, *rIN_LIBRARY;
+  pic_sym *rCOND_EXPAND;
 
   struct pic_lib *PICRIN_BASE;
   struct pic_lib *PICRIN_USER;
@@ -175,11 +175,11 @@ bool pic_eq_p(pic_value, pic_value);
 bool pic_eqv_p(pic_value, pic_value);
 bool pic_equal_p(pic_state *, pic_value, pic_value);
 
-pic_sym pic_intern(pic_state *, pic_str *);
-pic_sym pic_intern_cstr(pic_state *, const char *);
-const char *pic_symbol_name(pic_state *, pic_sym);
-pic_sym pic_gensym(pic_state *, pic_sym);
-bool pic_interned_p(pic_state *, pic_sym);
+pic_sym *pic_intern(pic_state *, pic_str *);
+pic_sym *pic_intern_cstr(pic_state *, const char *);
+const char *pic_symbol_name(pic_state *, pic_sym *);
+pic_sym *pic_gensym(pic_state *, pic_sym *);
+bool pic_interned_p(pic_state *, pic_sym *);
 
 pic_value pic_read(pic_state *, struct pic_port *);
 pic_value pic_read_cstr(pic_state *, const char *);
@@ -216,7 +216,7 @@ struct pic_lib *pic_find_library(pic_state *, pic_value);
 
 void pic_import(pic_state *, pic_value);
 void pic_import_library(pic_state *, struct pic_lib *);
-void pic_export(pic_state *, pic_sym);
+void pic_export(pic_state *, pic_sym *);
 
 pic_noreturn void pic_panic(pic_state *, const char *);
 pic_noreturn void pic_errorf(pic_state *, const char *, ...);
diff --git a/extlib/benz/include/picrin/dict.h b/extlib/benz/include/picrin/dict.h
index cfbd4855..13379bf5 100644
--- a/extlib/benz/include/picrin/dict.h
+++ b/extlib/benz/include/picrin/dict.h
@@ -23,14 +23,14 @@ struct pic_dict *pic_make_dict(pic_state *);
   pic_dict_for_each_helper_((sym), PIC_GENSYM(tmp), (dict))
 #define pic_dict_for_each_helper_(var, tmp, dict)                       \
   for (xh_entry *tmp = xh_begin(&dict->hash);                           \
-       (tmp && ((var = xh_key(tmp, pic_sym)), 1));                      \
+       (tmp && ((var = xh_key(tmp, pic_sym *)), 1));                    \
        tmp = xh_next(tmp))
 
-pic_value pic_dict_ref(pic_state *, struct pic_dict *, pic_sym);
-void pic_dict_set(pic_state *, struct pic_dict *, pic_sym, pic_value);
-void pic_dict_del(pic_state *, struct pic_dict *, pic_sym);
+pic_value pic_dict_ref(pic_state *, struct pic_dict *, pic_sym *);
+void pic_dict_set(pic_state *, struct pic_dict *, pic_sym *, pic_value);
+void pic_dict_del(pic_state *, struct pic_dict *, pic_sym *);
 size_t pic_dict_size(pic_state *, struct pic_dict *);
-bool pic_dict_has(pic_state *, struct pic_dict *, pic_sym);
+bool pic_dict_has(pic_state *, struct pic_dict *, pic_sym *);
 
 #if defined(__cplusplus)
 }
diff --git a/extlib/benz/include/picrin/error.h b/extlib/benz/include/picrin/error.h
index e4cc630a..3a575cfe 100644
--- a/extlib/benz/include/picrin/error.h
+++ b/extlib/benz/include/picrin/error.h
@@ -13,7 +13,7 @@ extern "C" {
 
 struct pic_error {
   PIC_OBJECT_HEADER
-  pic_sym type;
+  pic_sym *type;
   pic_str *msg;
   pic_value irrs;
   pic_str *stack;
@@ -22,7 +22,7 @@ struct pic_error {
 #define pic_error_p(v) (pic_type(v) == PIC_TT_ERROR)
 #define pic_error_ptr(v) ((struct pic_error *)pic_ptr(v))
 
-struct pic_error *pic_make_error(pic_state *, pic_sym, const char *, pic_list);
+struct pic_error *pic_make_error(pic_state *, pic_sym *, const char *, pic_list);
 
 /* do not return from try block! */
 
@@ -44,7 +44,7 @@ void pic_pop_try(pic_state *);
 
 pic_value pic_raise_continuable(pic_state *, pic_value);
 pic_noreturn void pic_raise(pic_state *, pic_value);
-pic_noreturn void pic_throw(pic_state *, pic_sym, const char *, pic_list);
+pic_noreturn void pic_throw(pic_state *, pic_sym *, const char *, pic_list);
 pic_noreturn void pic_error(pic_state *, const char *, pic_list);
 
 #if defined(__cplusplus)
diff --git a/extlib/benz/include/picrin/irep.h b/extlib/benz/include/picrin/irep.h
index 80159547..9c7932da 100644
--- a/extlib/benz/include/picrin/irep.h
+++ b/extlib/benz/include/picrin/irep.h
@@ -62,13 +62,13 @@ struct pic_code {
 
 struct pic_irep {
   PIC_OBJECT_HEADER
-  pic_sym name;
+  pic_sym *name;
   pic_code *code;
   int argc, localc, capturec;
   bool varg;
   struct pic_irep **irep;
   pic_value *pool;
-  pic_sym *syms;
+  pic_sym **syms;
   size_t clen, ilen, plen, slen;
 };
 
diff --git a/extlib/benz/include/picrin/macro.h b/extlib/benz/include/picrin/macro.h
index e79c4251..07ca86d1 100644
--- a/extlib/benz/include/picrin/macro.h
+++ b/extlib/benz/include/picrin/macro.h
@@ -22,15 +22,15 @@ struct pic_senv {
 struct pic_senv *pic_null_syntactic_environment(pic_state *);
 
 bool pic_identifier_p(pic_state *pic, pic_value obj);
-bool pic_identifier_eq_p(pic_state *, struct pic_senv *, pic_sym, struct pic_senv *, pic_sym);
+bool pic_identifier_eq_p(pic_state *, struct pic_senv *, pic_sym *, struct pic_senv *, pic_sym *);
 
 struct pic_senv *pic_make_senv(pic_state *, struct pic_senv *);
 
-pic_sym pic_add_rename(pic_state *, struct pic_senv *, pic_sym);
-bool pic_find_rename(pic_state *, struct pic_senv *, pic_sym, pic_sym * /* = NULL */);
-void pic_put_rename(pic_state *, struct pic_senv *, pic_sym, pic_sym);
+pic_sym *pic_add_rename(pic_state *, struct pic_senv *, pic_sym *);
+bool pic_find_rename(pic_state *, struct pic_senv *, pic_sym *, pic_sym ** /* = NULL */);
+void pic_put_rename(pic_state *, struct pic_senv *, pic_sym *, pic_sym *);
 
-void pic_define_syntactic_keyword(pic_state *, struct pic_senv *, pic_sym, pic_sym);
+void pic_define_syntactic_keyword(pic_state *, struct pic_senv *, pic_sym *, pic_sym *);
 
 #if defined(__cplusplus)
 }
diff --git a/extlib/benz/include/picrin/proc.h b/extlib/benz/include/picrin/proc.h
index e64cd6fc..ebe13a82 100644
--- a/extlib/benz/include/picrin/proc.h
+++ b/extlib/benz/include/picrin/proc.h
@@ -12,7 +12,7 @@ extern "C" {
 /* native C function */
 struct pic_func {
   pic_func_t f;
-  pic_sym name;
+  pic_sym *name;
 };
 
 struct pic_env {
@@ -48,7 +48,7 @@ struct pic_proc {
 struct pic_proc *pic_make_proc(pic_state *, pic_func_t, const char *);
 struct pic_proc *pic_make_proc_irep(pic_state *, struct pic_irep *, struct pic_env *);
 
-pic_sym pic_proc_name(struct pic_proc *);
+pic_sym *pic_proc_name(struct pic_proc *);
 
 #if defined(__cplusplus)
 }
diff --git a/extlib/benz/include/picrin/record.h b/extlib/benz/include/picrin/record.h
index 97476ce4..e3edcd01 100644
--- a/extlib/benz/include/picrin/record.h
+++ b/extlib/benz/include/picrin/record.h
@@ -20,8 +20,8 @@ struct pic_record {
 struct pic_record *pic_make_record(pic_state *, pic_value);
 
 pic_value pic_record_type(pic_state *, struct pic_record *);
-pic_value pic_record_ref(pic_state *, struct pic_record *, pic_sym);
-void pic_record_set(pic_state *, struct pic_record *, pic_sym, pic_value);
+pic_value pic_record_ref(pic_state *, struct pic_record *, pic_sym *);
+void pic_record_set(pic_state *, struct pic_record *, pic_sym *, pic_value);
 
 #if defined(__cplusplus)
 }
diff --git a/extlib/benz/include/picrin/value.h b/extlib/benz/include/picrin/value.h
index 8eb407e4..a6db5b98 100644
--- a/extlib/benz/include/picrin/value.h
+++ b/extlib/benz/include/picrin/value.h
@@ -133,7 +133,7 @@ struct pic_error;
 
 /* set aliases to basic types */
 typedef pic_value pic_list;
-typedef struct pic_symbol *pic_sym;
+typedef struct pic_symbol pic_sym;
 typedef struct pic_pair pic_pair;
 typedef struct pic_string pic_str;
 typedef struct pic_vector pic_vec;
diff --git a/extlib/benz/lib.c b/extlib/benz/lib.c
index ca738790..4a82a981 100644
--- a/extlib/benz/lib.c
+++ b/extlib/benz/lib.c
@@ -74,7 +74,7 @@ import_table(pic_state *pic, pic_value spec, struct pic_dict *imports)
   struct pic_lib *lib;
   struct pic_dict *table;
   pic_value val, tmp, prefix;
-  pic_sym sym, id, tag;
+  pic_sym *sym, *id, *tag;
 
   table = pic_make_dict(pic);
 
@@ -131,7 +131,7 @@ static void
 import(pic_state *pic, pic_value spec)
 {
   struct pic_dict *imports;
-  pic_sym sym;
+  pic_sym *sym;
 
   imports = pic_make_dict(pic);
 
@@ -145,9 +145,9 @@ import(pic_state *pic, pic_value spec)
 static void
 export(pic_state *pic, pic_value spec)
 {
-  const pic_sym sRENAME = pic_intern_cstr(pic, "rename");
+  pic_sym *sRENAME = pic_intern_cstr(pic, "rename");
   pic_value a, b;
-  pic_sym rename;
+  pic_sym *rename;
 
   if (pic_sym_p(spec)) {        /* (export a) */
     a = b = spec;
@@ -193,7 +193,7 @@ pic_import_library(pic_state *pic, struct pic_lib *lib)
 }
 
 void
-pic_export(pic_state *pic, pic_sym sym)
+pic_export(pic_state *pic, pic_sym *sym)
 {
   export(pic, pic_obj_value(sym));
 }
@@ -201,7 +201,7 @@ pic_export(pic_state *pic, pic_sym sym)
 static bool
 condexpand(pic_state *pic, pic_value clause)
 {
-  pic_sym tag;
+  pic_sym *tag;
   pic_value c, feature;
 
   if (pic_eq_p(clause, pic_obj_value(pic->sELSE))) {
@@ -335,7 +335,7 @@ pic_lib_in_library(pic_state *pic)
 void
 pic_init_lib(pic_state *pic)
 {
-  void pic_defmacro(pic_state *, pic_sym, pic_sym, pic_func_t);
+  void pic_defmacro(pic_state *, pic_sym *, pic_sym *, pic_func_t);
 
   pic_defmacro(pic, pic->sCOND_EXPAND, pic->rCOND_EXPAND, pic_lib_condexpand);
   pic_defmacro(pic, pic->sIMPORT, pic->rIMPORT, pic_lib_import);
diff --git a/extlib/benz/macro.c b/extlib/benz/macro.c
index f20b775f..622a28d3 100644
--- a/extlib/benz/macro.c
+++ b/extlib/benz/macro.c
@@ -13,10 +13,10 @@
 #include "picrin/cont.h"
 #include "picrin/symbol.h"
 
-pic_sym
-pic_add_rename(pic_state *pic, struct pic_senv *senv, pic_sym sym)
+pic_sym *
+pic_add_rename(pic_state *pic, struct pic_senv *senv, pic_sym *sym)
 {
-  pic_sym rename;
+  pic_sym *rename;
 
   rename = pic_gensym(pic, sym);
   pic_put_rename(pic, senv, sym, rename);
@@ -24,13 +24,13 @@ pic_add_rename(pic_state *pic, struct pic_senv *senv, pic_sym sym)
 }
 
 void
-pic_put_rename(pic_state *pic, struct pic_senv *senv, pic_sym sym, pic_sym rename)
+pic_put_rename(pic_state *pic, struct pic_senv *senv, pic_sym *sym, pic_sym *rename)
 {
   pic_dict_set(pic, senv->map, sym, pic_obj_value(rename));
 }
 
 bool
-pic_find_rename(pic_state *pic, struct pic_senv *senv, pic_sym sym, pic_sym *rename)
+pic_find_rename(pic_state *pic, struct pic_senv *senv, pic_sym *sym, pic_sym **rename)
 {
   if (! pic_dict_has(pic, senv->map, sym)) {
     return false;
@@ -42,13 +42,13 @@ 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 *mac)
+define_macro(pic_state *pic, pic_sym *rename, struct pic_proc *mac)
 {
   pic_dict_set(pic, pic->macros, rename, pic_obj_value(mac));
 }
 
 static struct pic_proc *
-find_macro(pic_state *pic, pic_sym rename)
+find_macro(pic_state *pic, pic_sym *rename)
 {
   if (! pic_dict_has(pic, pic->macros, rename)) {
     return NULL;
@@ -56,10 +56,10 @@ find_macro(pic_state *pic, pic_sym rename)
   return pic_proc_ptr(pic_dict_ref(pic, pic->macros, rename));
 }
 
-static pic_sym
-make_identifier(pic_state *pic, pic_sym sym, struct pic_senv *senv)
+static pic_sym *
+make_identifier(pic_state *pic, pic_sym *sym, struct pic_senv *senv)
 {
-  pic_sym rename;
+  pic_sym *rename;
 
   while (true) {
     if (pic_find_rename(pic, senv, sym, &rename)) {
@@ -81,7 +81,7 @@ static pic_value macroexpand(pic_state *, pic_value, struct pic_senv *);
 static pic_value macroexpand_lambda(pic_state *, pic_value, struct pic_senv *);
 
 static pic_value
-macroexpand_symbol(pic_state *pic, pic_sym sym, struct pic_senv *senv)
+macroexpand_symbol(pic_state *pic, pic_sym *sym, struct pic_senv *senv)
 {
   return pic_obj_value(make_identifier(pic, sym, senv));
 }
@@ -179,7 +179,7 @@ macroexpand_lambda(pic_state *pic, pic_value expr, struct pic_senv *senv)
 static pic_value
 macroexpand_define(pic_state *pic, pic_value expr, struct pic_senv *senv)
 {
-  pic_sym sym, rename;
+  pic_sym *sym, *rename;
   pic_value var, val;
 
   while (pic_length(pic, expr) >= 2 && pic_pair_p(pic_cadr(pic, expr))) {
@@ -210,7 +210,7 @@ static pic_value
 macroexpand_defsyntax(pic_state *pic, pic_value expr, struct pic_senv *senv)
 {
   pic_value var, val;
-  pic_sym sym, rename;
+  pic_sym *sym, *rename;
 
   if (pic_length(pic, expr) != 3) {
     pic_errorf(pic, "syntax error");
@@ -295,7 +295,7 @@ macroexpand_node(pic_state *pic, pic_value expr, struct pic_senv *senv)
 
     car = macroexpand(pic, pic_car(pic, expr), senv);
     if (pic_sym_p(car)) {
-      pic_sym tag = pic_sym_ptr(car);
+      pic_sym *tag = pic_sym_ptr(car);
 
       if (tag == pic->rDEFINE_SYNTAX) {
         return macroexpand_defsyntax(pic, expr, senv);
@@ -407,7 +407,7 @@ pic_null_syntactic_environment(pic_state *pic)
 }
 
 void
-pic_define_syntactic_keyword(pic_state *pic, struct pic_senv *senv, pic_sym sym, pic_sym rsym)
+pic_define_syntactic_keyword(pic_state *pic, struct pic_senv *senv, pic_sym *sym, pic_sym *rsym)
 {
   pic_put_rename(pic, senv, sym, rsym);
 
@@ -430,7 +430,7 @@ defmacro_call(pic_state *pic)
 }
 
 void
-pic_defmacro(pic_state *pic, pic_sym name, pic_sym id, pic_func_t func)
+pic_defmacro(pic_state *pic, pic_sym *name, pic_sym *id, pic_func_t func)
 {
   struct pic_proc *proc, *trans;
 
@@ -455,9 +455,9 @@ pic_identifier_p(pic_state *pic, pic_value obj)
 }
 
 bool
-pic_identifier_eq_p(pic_state *pic, struct pic_senv *env1, pic_sym sym1, struct pic_senv *env2, pic_sym sym2)
+pic_identifier_eq_p(pic_state *pic, struct pic_senv *env1, pic_sym *sym1, struct pic_senv *env2, pic_sym *sym2)
 {
-  pic_sym a, b;
+  pic_sym *a, *b;
 
   a = make_identifier(pic, sym1, env1);
   if (a != make_identifier(pic, sym1, env1)) {
@@ -486,7 +486,7 @@ static pic_value
 pic_macro_make_identifier(pic_state *pic)
 {
   pic_value obj;
-  pic_sym sym;
+  pic_sym *sym;
 
   pic_get_args(pic, "mo", &sym, &obj);
 
@@ -498,7 +498,7 @@ pic_macro_make_identifier(pic_state *pic)
 static pic_value
 pic_macro_identifier_eq_p(pic_state *pic)
 {
-  pic_sym sym1, sym2;
+  pic_sym *sym1, *sym2;
   pic_value env1, env2;
 
   pic_get_args(pic, "omom", &env1, &sym1, &env2, &sym2);
diff --git a/extlib/benz/proc.c b/extlib/benz/proc.c
index 2b94201b..321a362e 100644
--- a/extlib/benz/proc.c
+++ b/extlib/benz/proc.c
@@ -34,7 +34,7 @@ pic_make_proc_irep(pic_state *pic, struct pic_irep *irep, struct pic_env *env)
   return proc;
 }
 
-pic_sym
+pic_sym *
 pic_proc_name(struct pic_proc *proc)
 {
   switch (proc->kind) {
diff --git a/extlib/benz/read.c b/extlib/benz/read.c
index f54427a0..979113c5 100644
--- a/extlib/benz/read.c
+++ b/extlib/benz/read.c
@@ -199,7 +199,7 @@ read_symbol(pic_state *pic, struct pic_port *port, const char *str)
 {
   size_t len, i;
   char *buf;
-  pic_sym sym;
+  pic_sym *sym;
   int c;
 
   len = strlen(str);
@@ -452,7 +452,7 @@ read_pipe(pic_state *pic, struct pic_port *port, const char *str)
 {
   char *buf;
   size_t size, cnt;
-  pic_sym sym;
+  pic_sym *sym;
   /* Currently supports only ascii chars */
   char HEX_BUF[3];
   size_t i = 0;
diff --git a/extlib/benz/record.c b/extlib/benz/record.c
index 331b43d4..2a6e85cc 100644
--- a/extlib/benz/record.c
+++ b/extlib/benz/record.c
@@ -29,7 +29,7 @@ pic_record_type(pic_state *pic, struct pic_record *rec)
 }
 
 pic_value
-pic_record_ref(pic_state *pic, struct pic_record *rec, pic_sym slot)
+pic_record_ref(pic_state *pic, struct pic_record *rec, pic_sym *slot)
 {
   if (! pic_dict_has(pic, rec->data, slot)) {
     pic_errorf(pic, "slot named ~s is not found for record: ~s", pic_obj_value(slot), rec);
@@ -38,7 +38,7 @@ pic_record_ref(pic_state *pic, struct pic_record *rec, pic_sym slot)
 }
 
 void
-pic_record_set(pic_state *pic, struct pic_record *rec, pic_sym slot, pic_value val)
+pic_record_set(pic_state *pic, struct pic_record *rec, pic_sym *slot, pic_value val)
 {
   pic_dict_set(pic, rec->data, slot, val);
 }
@@ -80,7 +80,7 @@ static pic_value
 pic_record_record_ref(pic_state *pic)
 {
   struct pic_record *rec;
-  pic_sym slot;
+  pic_sym *slot;
 
   pic_get_args(pic, "rm", &rec, &slot);
 
@@ -91,7 +91,7 @@ static pic_value
 pic_record_record_set(pic_state *pic)
 {
   struct pic_record *rec;
-  pic_sym slot;
+  pic_sym *slot;
   pic_value val;
 
   pic_get_args(pic, "rmo", &rec, &slot, &val);
diff --git a/extlib/benz/state.c b/extlib/benz/state.c
index a680c3ba..195f07ab 100644
--- a/extlib/benz/state.c
+++ b/extlib/benz/state.c
@@ -52,7 +52,7 @@ pic_open(int argc, char *argv[], char **envp)
   pic->heap = pic_heap_open();
 
   /* symbol table */
-  xh_init_str(&pic->syms, sizeof(pic_sym));
+  xh_init_str(&pic->syms, sizeof(pic_sym *));
 
   /* global variables */
   pic->globals = NULL;
diff --git a/extlib/benz/symbol.c b/extlib/benz/symbol.c
index 7acbbece..f8f091bd 100644
--- a/extlib/benz/symbol.c
+++ b/extlib/benz/symbol.c
@@ -6,26 +6,26 @@
 #include "picrin/symbol.h"
 #include "picrin/string.h"
 
-pic_sym
+pic_sym *
 pic_make_symbol(pic_state *pic, pic_str *str)
 {
-  pic_sym sym;
+  pic_sym *sym;
 
-  sym = (pic_sym)pic_obj_alloc(pic, sizeof(struct pic_symbol), PIC_TT_SYMBOL);
+  sym = (pic_sym *)pic_obj_alloc(pic, sizeof(struct pic_symbol), PIC_TT_SYMBOL);
   sym->str = str;
   return sym;
 }
 
-pic_sym
+pic_sym *
 pic_intern(pic_state *pic, pic_str *str)
 {
   xh_entry *e;
-  pic_sym sym;
+  pic_sym *sym;
   char *cstr;
 
   e = xh_get_str(&pic->syms, pic_str_cstr(str));
   if (e) {
-    sym = xh_val(e, pic_sym);
+    sym = xh_val(e, pic_sym *);
     pic_gc_protect(pic, pic_obj_value(sym));
     return sym;
   }
@@ -38,33 +38,33 @@ pic_intern(pic_state *pic, pic_str *str)
   return sym;
 }
 
-pic_sym
+pic_sym *
 pic_intern_cstr(pic_state *pic, const char *str)
 {
   return pic_intern(pic, pic_make_str(pic, str, strlen(str)));
 }
 
-pic_sym
-pic_gensym(pic_state *pic, pic_sym base)
+pic_sym *
+pic_gensym(pic_state *pic, pic_sym *base)
 {
   return pic_make_symbol(pic, base->str);
 }
 
 bool
-pic_interned_p(pic_state *pic, pic_sym sym)
+pic_interned_p(pic_state *pic, pic_sym *sym)
 {
   xh_entry *e;
 
   e = xh_get_str(&pic->syms, pic_str_cstr(sym->str));
   if (e) {
-    return sym == xh_val(e, pic_sym);
+    return sym == xh_val(e, pic_sym *);
   } else {
     return false;
   }
 }
 
 const char *
-pic_symbol_name(pic_state *pic, pic_sym sym)
+pic_symbol_name(pic_state *pic, pic_sym *sym)
 {
   PIC_UNUSED(pic);
 
@@ -103,7 +103,7 @@ pic_symbol_symbol_eq_p(pic_state *pic)
 static pic_value
 pic_symbol_symbol_to_string(pic_state *pic)
 {
-  pic_sym sym;
+  pic_sym *sym;
 
   pic_get_args(pic, "m", &sym);
 
diff --git a/extlib/benz/vm.c b/extlib/benz/vm.c
index ea46c9d2..0c82bdff 100644
--- a/extlib/benz/vm.c
+++ b/extlib/benz/vm.c
@@ -41,7 +41,7 @@ pic_get_proc(pic_state *pic)
  *  F   double *, bool *        float with exactness
  *  s   pic_str **              string object
  *  z   char **                 c string
- *  m   pic_sym *               symbol
+ *  m   pic_sym **              symbol
  *  v   pic_vec **              vector object
  *  b   pic_blob **             bytevector object
  *  c   char *                  char
@@ -255,10 +255,10 @@ pic_get_args(pic_state *pic, const char *format, ...)
       break;
     }
     case 'm': {
-      pic_sym *m;
+      pic_sym **m;
       pic_value v;
 
-      m = va_arg(ap, pic_sym *);
+      m = va_arg(ap, pic_sym **);
       if (i < argc) {
         v = GET_OPERAND(pic,i);
         if (pic_sym_p(v)) {
@@ -433,7 +433,7 @@ pic_get_args(pic_state *pic, const char *format, ...)
 void
 pic_define_noexport(pic_state *pic, const char *name, pic_value val)
 {
-  pic_sym sym, rename;
+  pic_sym *sym, *rename;
 
   sym = pic_intern_cstr(pic, name);
 
@@ -457,7 +457,7 @@ pic_define(pic_state *pic, const char *name, pic_value val)
 pic_value
 pic_ref(pic_state *pic, struct pic_lib *lib, const char *name)
 {
-  pic_sym sym, rename;
+  pic_sym *sym, *rename;
 
   sym = pic_intern_cstr(pic, name);
 
@@ -471,7 +471,7 @@ pic_ref(pic_state *pic, struct pic_lib *lib, const char *name)
 void
 pic_set(pic_state *pic, struct pic_lib *lib, const char *name, pic_value val)
 {
-  pic_sym sym, rename;
+  pic_sym *sym, *rename;
 
   sym = pic_intern_cstr(pic, name);
 
@@ -776,7 +776,7 @@ pic_apply(pic_state *pic, struct pic_proc *proc, pic_value args)
     }
     CASE(OP_GREF) {
       struct pic_irep *irep = vm_get_irep(pic);
-      pic_sym sym;
+      pic_sym *sym;
 
       sym = irep->syms[c.u.i];
       if (! pic_dict_has(pic, pic->globals, sym)) {
@@ -787,7 +787,7 @@ pic_apply(pic_state *pic, struct pic_proc *proc, pic_value args)
     }
     CASE(OP_GSET) {
       struct pic_irep *irep = vm_get_irep(pic);
-      pic_sym sym;
+      pic_sym *sym;
       pic_value val;
 
       sym = irep->syms[c.u.i];
diff --git a/extlib/benz/write.c b/extlib/benz/write.c
index 3fecb4bc..5fe657e2 100644
--- a/extlib/benz/write.c
+++ b/extlib/benz/write.c
@@ -14,7 +14,7 @@
 #include "picrin/symbol.h"
 
 static bool
-is_tagged(pic_state *pic, pic_sym tag, pic_value pair)
+is_tagged(pic_state *pic, pic_sym *tag, pic_value pair)
 {
   return pic_pair_p(pic_cdr(pic, pair))
     && pic_nil_p(pic_cddr(pic, pair))
@@ -176,7 +176,7 @@ write_str(pic_state *pic, struct pic_string *str, xFILE *file)
 static void
 write_record(pic_state *pic, struct pic_record *rec, xFILE *file)
 {
-  const pic_sym sWRITER = pic_intern_cstr(pic, "writer");
+  pic_sym *sWRITER = pic_intern_cstr(pic, "writer");
   pic_value type, writer, str;
 
 #if DEBUG
@@ -333,7 +333,7 @@ write_core(struct writer_control *p, pic_value obj)
   case PIC_TT_DICT:
     xfprintf(file, "#.(dictionary");
     for (it = xh_begin(&pic_dict_ptr(obj)->hash); it != NULL; it = xh_next(it)) {
-      xfprintf(file, " '%s ", pic_symbol_name(pic, xh_key(it, pic_sym)));
+      xfprintf(file, " '%s ", pic_symbol_name(pic, xh_key(it, pic_sym *)));
       write_core(p, xh_val(it, pic_value));
     }
     xfprintf(file, ")");