diff --git a/src/cs_val.cc b/src/cs_val.cc
index 2fa0fda..a9d20b7 100644
--- a/src/cs_val.cc
+++ b/src/cs_val.cc
@@ -4,6 +4,18 @@
 
 namespace cscript {
 
+static cs_string intstr(cs_int v) {
+    auto app = ostd::appender<cs_string>();
+    cscript::util::format_int(app, v);
+    return std::move(app.get());
+}
+
+static cs_string floatstr(cs_float v) {
+    auto app = ostd::appender<cs_string>();
+    cscript::util::format_float(app, v);
+    return std::move(app.get());
+}
+
 template<typename T>
 struct stor_priv_t {
     cs_shared_state *state;
diff --git a/src/cs_vm.cc b/src/cs_vm.cc
index 655502f..6196f36 100644
--- a/src/cs_vm.cc
+++ b/src/cs_vm.cc
@@ -1021,14 +1021,12 @@ static uint32_t *runcode(cs_state &cs, uint32_t *code, cs_value &result) {
                         arg.set_str(static_cast<cs_svar *>(id)->get_value());
                         continue;
                     case CsIdIvar:
-                        arg.set_str(
-                            intstr(static_cast<cs_ivar *>(id)->get_value())
-                        );
+                        arg.set_int(static_cast<cs_ivar *>(id)->get_value());
+                        arg.force_str();
                         continue;
                     case CsIdFvar:
-                        arg.set_str(
-                            floatstr(static_cast<cs_fvar *>(id)->get_value())
-                        );
+                        arg.set_float(static_cast<cs_fvar *>(id)->get_value());
+                        arg.force_str();
                         continue;
                     case CsIdUnknown:
                         arg.set_str("");
@@ -1189,14 +1187,12 @@ static uint32_t *runcode(cs_state &cs, uint32_t *code, cs_value &result) {
                         arg.set_str(static_cast<cs_svar *>(id)->get_value());
                         continue;
                     case CsIdIvar:
-                        arg.set_str(
-                            intstr(static_cast<cs_ivar *>(id)->get_value())
-                        );
+                        arg.set_int(static_cast<cs_ivar *>(id)->get_value());
+                        arg.force_str();
                         continue;
                     case CsIdFvar:
-                        arg.set_str(
-                            floatstr(static_cast<cs_fvar *>(id)->get_value())
-                        );
+                        arg.set_float(static_cast<cs_fvar *>(id)->get_value());
+                        arg.force_str();
                         continue;
                     case CsIdUnknown:
                         arg.set_str("");
@@ -1285,9 +1281,10 @@ static uint32_t *runcode(cs_state &cs, uint32_t *code, cs_value &result) {
                 )->get_value());
                 continue;
             case CS_CODE_IVAR | CS_RET_STRING:
-                args[numargs++].set_str(intstr(static_cast<cs_ivar *>(
+                args[numargs].set_int(static_cast<cs_ivar *>(
                     cs.p_state->identmap[op >> 8]
-                )->get_value()));
+                )->get_value());
+                args[numargs++].force_str();
                 continue;
             case CS_CODE_IVAR | CS_RET_FLOAT:
                 args[numargs++].set_float(cs_float(static_cast<cs_ivar *>(
@@ -1324,11 +1321,10 @@ static uint32_t *runcode(cs_state &cs, uint32_t *code, cs_value &result) {
                 )->get_value());
                 continue;
             case CS_CODE_FVAR | CS_RET_STRING:
-                args[numargs++].set_str(floatstr(
-                    static_cast<cs_fvar *>(
-                        cs.p_state->identmap[op >> 8]
-                    )->get_value()
-                ));
+                args[numargs].set_int(static_cast<cs_fvar *>(
+                    cs.p_state->identmap[op >> 8]
+                )->get_value());
+                args[numargs++].force_str();
                 continue;
             case CS_CODE_FVAR | CS_RET_INT:
                 args[numargs++].set_int(int(static_cast<cs_fvar *>(
diff --git a/src/cs_vm.hh b/src/cs_vm.hh
index 5c049c2..29bb898 100644
--- a/src/cs_vm.hh
+++ b/src/cs_vm.hh
@@ -314,9 +314,6 @@ struct cs_gen_state {
     void skip_comments();
 };
 
-cs_string intstr(cs_int v);
-cs_string floatstr(cs_float v);
-
 bool cs_check_num(ostd::string_range s);
 
 static inline void bcode_incr(uint32_t *bc) {
diff --git a/src/cubescript.cc b/src/cubescript.cc
index 6b95013..4d878de 100644
--- a/src/cubescript.cc
+++ b/src/cubescript.cc
@@ -3,18 +3,6 @@
 
 namespace cscript {
 
-cs_string intstr(cs_int v) {
-    auto app = ostd::appender<cs_string>();
-    cscript::util::format_int(app, v);
-    return std::move(app.get());
-}
-
-cs_string floatstr(cs_float v) {
-    auto app = ostd::appender<cs_string>();
-    cscript::util::format_float(app, v);
-    return std::move(app.get());
-}
-
 bool cs_check_num(ostd::string_range s) {
     if (isdigit(s[0])) {
         return true;
@@ -879,9 +867,12 @@ cs_float cs_clamp_fvar(cs_state &cs, cs_fvar *fv, cs_float v) {
     } else {
         return v;
     }
+    cs_value vmin{cs}, vmax{cs};
+    vmin.set_float(fv->get_val_min());
+    vmax.set_float(fv->get_val_max());
     throw cs_error(
-        cs, "valid range for '%s' is %s..%s", floatstr(fv->get_val_min()),
-        floatstr(fv->get_val_max())
+        cs, "valid range for '%s' is %s..%s", fv->get_name(),
+        vmin.force_str(), vmax.force_str()
     );
     return v;
 }