diff --git a/contrib/20.r7rs/src/file.c b/contrib/20.r7rs/src/file.c
index dd94803c..9aeae3d4 100644
--- a/contrib/20.r7rs/src/file.c
+++ b/contrib/20.r7rs/src/file.c
@@ -11,7 +11,7 @@ file_error(pic_state *pic, const char *msg)
 {
   struct pic_error *e;
 
-  e = pic_make_error(pic, pic_intern_cstr(pic, "file"), msg, pic_nil_value());
+  e = pic_make_error(pic, pic_intern(pic, "file"), msg, pic_nil_value());
 
   pic_raise(pic, pic_obj_value(e));
 }
diff --git a/extlib/benz/attr.c b/extlib/benz/attr.c
index 3e0bb192..ca11fa07 100644
--- a/extlib/benz/attr.c
+++ b/extlib/benz/attr.c
@@ -22,13 +22,13 @@ pic_attr(pic_state *pic, pic_value obj)
 pic_value
 pic_attr_ref(pic_state *pic, pic_value obj, const char *key)
 {
-  return pic_dict_ref(pic, pic_attr(pic, obj), pic_intern_cstr(pic, key));
+  return pic_dict_ref(pic, pic_attr(pic, obj), pic_intern(pic, key));
 }
 
 void
 pic_attr_set(pic_state *pic, pic_value obj, const char *key, pic_value v)
 {
-  pic_dict_set(pic, pic_attr(pic, obj), pic_intern_cstr(pic, key), v);
+  pic_dict_set(pic, pic_attr(pic, obj), pic_intern(pic, key), v);
 }
 
 static pic_value
diff --git a/extlib/benz/debug.c b/extlib/benz/debug.c
index 040b12a8..7d682f0f 100644
--- a/extlib/benz/debug.c
+++ b/extlib/benz/debug.c
@@ -45,7 +45,7 @@ pic_print_backtrace(pic_state *pic, xFILE *file)
     pic_value elem, it;
 
     e = pic_error_ptr(pic->err);
-    if (e->type != pic_intern_cstr(pic, "")) {
+    if (e->type != pic_intern(pic, "")) {
       pic_fwrite(pic, pic_obj_value(e->type), file);
       xfprintf(pic, file, " ");
     }
diff --git a/extlib/benz/error.c b/extlib/benz/error.c
index 927ad2ec..67a7cdc0 100644
--- a/extlib/benz/error.c
+++ b/extlib/benz/error.c
@@ -158,7 +158,7 @@ pic_error(pic_state *pic, const char *msg, pic_value irrs)
 {
   struct pic_error *e;
 
-  e = pic_make_error(pic, pic_intern_cstr(pic, ""), msg, irrs);
+  e = pic_make_error(pic, pic_intern(pic, ""), msg, irrs);
 
   pic_raise(pic, pic_obj_value(e));
 }
diff --git a/extlib/benz/include/picrin.h b/extlib/benz/include/picrin.h
index ad7bf419..ada531fd 100644
--- a/extlib/benz/include/picrin.h
+++ b/extlib/benz/include/picrin.h
@@ -172,8 +172,8 @@ 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 *);
+pic_sym *pic_intern(pic_state *, const char *);
+pic_sym *pic_intern_str(pic_state *, pic_str *);
 const char *pic_symbol_name(pic_state *, pic_sym *);
 
 pic_value pic_read(pic_state *, struct pic_port *);
diff --git a/extlib/benz/macro.c b/extlib/benz/macro.c
index cac07fd5..8bca193f 100644
--- a/extlib/benz/macro.c
+++ b/extlib/benz/macro.c
@@ -56,7 +56,7 @@ pic_uniq(pic_state *pic, pic_value var)
 
   str = pic_format(pic, "%s.%d", pic_symbol_name(pic, pic_var_name(pic, var)), pic->ucnt++);
 
-  return pic_intern(pic, str);
+  return pic_intern_str(pic, str);
 }
 
 pic_sym *
diff --git a/extlib/benz/port.c b/extlib/benz/port.c
index 337d0ecd..9b4b605d 100644
--- a/extlib/benz/port.c
+++ b/extlib/benz/port.c
@@ -103,7 +103,7 @@ file_error(pic_state *pic, const char *msg)
 {
   struct pic_error *e;
 
-  e = pic_make_error(pic, pic_intern_cstr(pic, "file"), msg, pic_nil_value());
+  e = pic_make_error(pic, pic_intern(pic, "file"), msg, pic_nil_value());
 
   pic_raise(pic, pic_obj_value(e));
 }
diff --git a/extlib/benz/proc.c b/extlib/benz/proc.c
index 4c00885b..d7a5bca1 100644
--- a/extlib/benz/proc.c
+++ b/extlib/benz/proc.c
@@ -42,19 +42,19 @@ pic_proc_env(pic_state *pic, struct pic_proc *proc)
 bool
 pic_proc_env_has(pic_state *pic, struct pic_proc *proc, const char *key)
 {
-  return pic_dict_has(pic, pic_proc_env(pic, proc), pic_intern_cstr(pic, key));
+  return pic_dict_has(pic, pic_proc_env(pic, proc), pic_intern(pic, key));
 }
 
 pic_value
 pic_proc_env_ref(pic_state *pic, struct pic_proc *proc, const char *key)
 {
-  return pic_dict_ref(pic, pic_proc_env(pic, proc), pic_intern_cstr(pic, key));
+  return pic_dict_ref(pic, pic_proc_env(pic, proc), pic_intern(pic, key));
 }
 
 void
 pic_proc_env_set(pic_state *pic, struct pic_proc *proc, const char *key, pic_value val)
 {
-  pic_dict_set(pic, pic_proc_env(pic, proc), pic_intern_cstr(pic, key), val);
+  pic_dict_set(pic, pic_proc_env(pic, proc), pic_intern(pic, key), val);
 }
 
 static pic_value
diff --git a/extlib/benz/read.c b/extlib/benz/read.c
index 77cce237..09278225 100644
--- a/extlib/benz/read.c
+++ b/extlib/benz/read.c
@@ -14,7 +14,7 @@ read_error(pic_state *pic, const char *msg)
 {
   struct pic_error *e;
 
-  e = pic_make_error(pic, pic_intern_cstr(pic, "read"), msg, pic_nil_value());
+  e = pic_make_error(pic, pic_intern(pic, "read"), msg, pic_nil_value());
 
   pic_raise(pic, pic_obj_value(e));
 }
@@ -216,7 +216,7 @@ read_symbol(pic_state *pic, struct pic_port *port, int c)
     buf[len] = 0;
   }
 
-  sym = pic_intern_cstr(pic, buf);
+  sym = pic_intern(pic, buf);
   pic_free(pic, buf);
 
   return pic_obj_value(sym);
@@ -537,7 +537,7 @@ read_pipe(pic_state *pic, struct pic_port *port, int c)
   }
   buf[cnt] = '\0';
 
-  sym = pic_intern_cstr(pic, buf);
+  sym = pic_intern(pic, buf);
   pic_free(pic, buf);
 
   return pic_obj_value(sym);
diff --git a/extlib/benz/record.c b/extlib/benz/record.c
index dfa21908..db14159e 100644
--- a/extlib/benz/record.c
+++ b/extlib/benz/record.c
@@ -15,7 +15,7 @@ pic_make_record(pic_state *pic, pic_value rectype)
   rec = (struct pic_record *)pic_obj_alloc(pic, sizeof(struct pic_record), PIC_TT_RECORD);
   rec->data = data;
 
-  pic_record_set(pic, rec, pic_intern_cstr(pic, "@@type"), rectype);
+  pic_record_set(pic, rec, pic_intern(pic, "@@type"), rectype);
 
   return rec;
 }
@@ -23,7 +23,7 @@ pic_make_record(pic_state *pic, pic_value rectype)
 pic_value
 pic_record_type(pic_state *pic, struct pic_record *rec)
 {
-  return pic_record_ref(pic, rec, pic_intern_cstr(pic, "@@type"));
+  return pic_record_ref(pic, rec, pic_intern(pic, "@@type"));
 }
 
 pic_value
diff --git a/extlib/benz/state.c b/extlib/benz/state.c
index 2fb447a3..8e03f6c4 100644
--- a/extlib/benz/state.c
+++ b/extlib/benz/state.c
@@ -15,7 +15,7 @@ pic_set_argv(pic_state *pic, int argc, char *argv[], char **envp)
 void
 pic_add_feature(pic_state *pic, const char *feature)
 {
-  pic_push(pic, pic_obj_value(pic_intern_cstr(pic, feature)), pic->features);
+  pic_push(pic, pic_obj_value(pic_intern(pic, feature)), pic->features);
 }
 
 void pic_init_undef(pic_state *);
@@ -113,10 +113,10 @@ pic_features(pic_state *pic)
 #define DONE pic_gc_arena_restore(pic, ai);
 
 #define define_builtin_syntax(uid, name)                                \
-  pic_define_syntactic_keyword_(pic, pic->lib->env, pic_intern_cstr(pic, name), uid)
+  pic_define_syntactic_keyword_(pic, pic->lib->env, pic_intern(pic, name), uid)
 
 #define VM(uid, name)                                                   \
-  pic_define_syntactic_keyword_(pic, pic->lib->env, pic_intern_cstr(pic, name), uid)
+  pic_define_syntactic_keyword_(pic, pic->lib->env, pic_intern(pic, name), uid)
 
 #define VM3(name)                                       \
   pic->c##name = pic_vm_gref_slot(pic, pic->u##name);
@@ -343,7 +343,7 @@ pic_open(pic_allocf allocf, void *userdata)
 
   ai = pic_gc_arena_preserve(pic);
 
-#define S(slot,name) pic->slot = pic_intern_cstr(pic, name)
+#define S(slot,name) pic->slot = pic_intern(pic, name)
 
   S(sQUOTE, "quote");
   S(sQUASIQUOTE, "quasiquote");
@@ -364,7 +364,7 @@ pic_open(pic_allocf allocf, void *userdata)
 
   pic_gc_arena_restore(pic, ai);
 
-#define U(slot,name) pic->slot = pic_uniq(pic, pic_obj_value(pic_intern_cstr(pic, name)))
+#define U(slot,name) pic->slot = pic_uniq(pic, pic_obj_value(pic_intern(pic, name)))
 
   U(uDEFINE, "define");
   U(uLAMBDA, "lambda");
diff --git a/extlib/benz/symbol.c b/extlib/benz/symbol.c
index ba5fb47c..5dec1035 100644
--- a/extlib/benz/symbol.c
+++ b/extlib/benz/symbol.c
@@ -7,13 +7,13 @@
 KHASH_DEFINE(s, const char *, pic_sym *, kh_str_hash_func, kh_str_hash_equal)
 
 pic_sym *
-pic_intern(pic_state *pic, pic_str *str)
+pic_intern_str(pic_state *pic, pic_str *str)
 {
-  return pic_intern_cstr(pic, pic_str_cstr(pic, str));
+  return pic_intern(pic, pic_str_cstr(pic, str));
 }
 
 pic_sym *
-pic_intern_cstr(pic_state *pic, const char *cstr)
+pic_intern(pic_state *pic, const char *cstr)
 {
   khash_t(s) *h = &pic->syms;
   pic_sym *sym;
@@ -93,7 +93,7 @@ pic_symbol_string_to_symbol(pic_state *pic)
 
   pic_get_args(pic, "s", &str);
 
-  return pic_obj_value(pic_intern(pic, str));
+  return pic_obj_value(pic_intern_str(pic, str));
 }
 
 void
diff --git a/extlib/benz/vm.c b/extlib/benz/vm.c
index dd719d24..b47849f0 100644
--- a/extlib/benz/vm.c
+++ b/extlib/benz/vm.c
@@ -1113,7 +1113,7 @@ pic_define_(pic_state *pic, const char *name, pic_value val)
 {
   pic_sym *sym, *uid;
 
-  sym = pic_intern_cstr(pic, name);
+  sym = pic_intern(pic, name);
 
   if ((uid = pic_find_variable(pic, pic->lib->env, pic_obj_value(sym))) == NULL) {
     uid = pic_add_variable(pic, pic->lib->env, pic_obj_value(sym));
@@ -1130,7 +1130,7 @@ void
 pic_define(pic_state *pic, const char *name, pic_value val)
 {
   pic_define_(pic, name, val);
-  pic_export(pic, pic_intern_cstr(pic, name));
+  pic_export(pic, pic_intern(pic, name));
 }
 
 void
@@ -1143,7 +1143,7 @@ void
 pic_defun(pic_state *pic, const char *name, pic_func_t cfunc)
 {
   pic_defun_(pic, name, cfunc);
-  pic_export(pic, pic_intern_cstr(pic, name));
+  pic_export(pic, pic_intern(pic, name));
 }
 
 void
@@ -1156,7 +1156,7 @@ void
 pic_defvar(pic_state *pic, const char *name, pic_value init, struct pic_proc *conv)
 {
   pic_defvar_(pic, name, init, conv);
-  pic_export(pic, pic_intern_cstr(pic, name));
+  pic_export(pic, pic_intern(pic, name));
 }
 
 pic_value
@@ -1164,7 +1164,7 @@ pic_ref(pic_state *pic, struct pic_lib *lib, const char *name)
 {
   pic_sym *sym, *uid;
 
-  sym = pic_intern_cstr(pic, name);
+  sym = pic_intern(pic, name);
 
   if ((uid = pic_find_variable(pic, lib->env, pic_obj_value(sym))) == NULL) {
     pic_errorf(pic, "symbol \"%s\" not defined in library ~s", name, lib->name);
@@ -1178,7 +1178,7 @@ pic_set(pic_state *pic, struct pic_lib *lib, const char *name, pic_value val)
 {
   pic_sym *sym, *uid;
 
-  sym = pic_intern_cstr(pic, name);
+  sym = pic_intern(pic, name);
 
   if ((uid = pic_find_variable(pic, lib->env, pic_obj_value(sym))) == NULL) {
     pic_errorf(pic, "symbol \"%s\" not defined in library ~s", name, lib->name);