diff --git a/include/cubescript/cubescript.hh b/include/cubescript/cubescript.hh
index ceee42b..6caeb9e 100644
--- a/include/cubescript/cubescript.hh
+++ b/include/cubescript/cubescript.hh
@@ -345,15 +345,22 @@ struct LIBCUBESCRIPT_EXPORT state {
 
     void init_libs(int libs = LIB_ALL);
 
+    void clear_override(ident &id);
+    void clear_overrides();
+
     integer_var *new_ivar(
-        std::string_view n, integer_type v, bool read_only = false
+        std::string_view n, integer_type v, bool read_only = false,
+        var_type vtp = var_type::DEFAULT
     );
     float_var *new_fvar(
-        std::string_view n, float_type v, bool read_only = false
+        std::string_view n, float_type v, bool read_only = false,
+        var_type vtp = var_type::DEFAULT
     );
     string_var *new_svar(
-        std::string_view n, std::string_view v, bool read_only = false
+        std::string_view n, std::string_view v, bool read_only = false,
+        var_type vtp = var_type::DEFAULT
     );
+    void reset_var(std::string_view name);
 
     template<typename F>
     command *new_command(
diff --git a/src/cs_state.cc b/src/cs_state.cc
index 7be91a3..e714d73 100644
--- a/src/cs_state.cc
+++ b/src/cs_state.cc
@@ -288,39 +288,119 @@ LIBCUBESCRIPT_EXPORT std::span<ident const *> state::get_idents() const {
     return std::span<ident const *>{ptr, p_tstate->istate->identmap.size()};
 }
 
+LIBCUBESCRIPT_EXPORT void state::clear_override(ident &id) {
+    if (!id.is_overridden(*this)) {
+        return;
+    }
+    switch (id.get_type()) {
+        case ident_type::ALIAS: {
+            auto &ast = p_tstate->get_astack(static_cast<alias *>(&id));
+            ast.node->val_s.set_str("");
+            ast.node->code = bcode_ref{};
+            ast.flags &= ~IDENT_FLAG_OVERRIDDEN;
+            return;
+        }
+        case ident_type::IVAR: {
+            ivar_impl &iv = static_cast<ivar_impl &>(id);
+            iv.set_value(iv.p_override);
+            //iv.changed(*this);
+            static_cast<ivar_impl *>(
+                static_cast<integer_var *>(&iv)
+            )->p_flags &= ~IDENT_FLAG_OVERRIDDEN;
+            return;
+        }
+        case ident_type::FVAR: {
+            fvar_impl &fv = static_cast<fvar_impl &>(id);
+            fv.set_value(fv.p_override);
+            //fv.changed(*this);
+            static_cast<fvar_impl *>(
+                static_cast<float_var *>(&fv)
+            )->p_flags &= ~IDENT_FLAG_OVERRIDDEN;
+            return;
+        }
+        case ident_type::SVAR: {
+            svar_impl &sv = static_cast<svar_impl &>(id);
+            sv.set_value(sv.p_override);
+            //sv.changed(*this);
+            static_cast<svar_impl *>(
+                static_cast<string_var *>(&sv)
+            )->p_flags &= ~IDENT_FLAG_OVERRIDDEN;
+            return;
+        }
+        default:
+            break;
+    }
+}
+
+LIBCUBESCRIPT_EXPORT void state::clear_overrides() {
+    for (auto &p: p_tstate->istate->idents) {
+        clear_override(*(p.second));
+    }
+}
+
+inline int var_flags(bool read_only, var_type vtp) {
+    int ret = 0;
+    if (read_only) {
+        ret |= IDENT_FLAG_READONLY;
+    }
+    switch (vtp) {
+        case var_type::PERSISTENT:
+            ret |= IDENT_FLAG_PERSIST;
+            break;
+        case var_type::OVERRIDABLE:
+            ret |= IDENT_FLAG_OVERRIDE;
+            break;
+        default:
+            break;
+    }
+    return ret;
+}
+
 LIBCUBESCRIPT_EXPORT integer_var *state::new_ivar(
-    std::string_view n, integer_type v, bool read_only
+    std::string_view n, integer_type v, bool read_only, var_type vtp
 ) {
     auto *iv = p_tstate->istate->create<ivar_impl>(
         string_ref{p_tstate->istate, n}, v,
-        read_only ? IDENT_FLAG_READONLY : 0
+        var_flags(read_only, vtp)
     );
     p_tstate->istate->add_ident(iv, iv);
     return iv;
 }
 
 LIBCUBESCRIPT_EXPORT float_var *state::new_fvar(
-    std::string_view n, float_type v, bool read_only
+    std::string_view n, float_type v, bool read_only, var_type vtp
 ) {
     auto *fv = p_tstate->istate->create<fvar_impl>(
         string_ref{p_tstate->istate, n}, v,
-        read_only ? IDENT_FLAG_READONLY : 0
+        var_flags(read_only, vtp)
     );
     p_tstate->istate->add_ident(fv, fv);
     return fv;
 }
 
 LIBCUBESCRIPT_EXPORT string_var *state::new_svar(
-    std::string_view n, std::string_view v, bool read_only
+    std::string_view n, std::string_view v, bool read_only, var_type vtp
 ) {
     auto *sv = p_tstate->istate->create<svar_impl>(
         string_ref{p_tstate->istate, n}, string_ref{p_tstate->istate, v},
-        read_only ? IDENT_FLAG_READONLY : 0
+        var_flags(read_only, vtp)
     );
     p_tstate->istate->add_ident(sv, sv);
     return sv;
 }
 
+LIBCUBESCRIPT_EXPORT void state::reset_var(std::string_view name) {
+    ident *id = get_ident(name);
+    if (!id) {
+        throw error{*this, "variable '%s' does not exist", name.data()};
+    }
+    auto *var = id->get_var();
+    if (var && var->is_read_only()) {
+        throw error{*this, "variable '%s' is read only", name.data()};
+    }
+    clear_override(*id);
+}
+
 LIBCUBESCRIPT_EXPORT void state::set_alias(
     std::string_view name, any_value v
 ) {
diff --git a/src/lib_base.cc b/src/lib_base.cc
index c7a005b..c26e3ef 100644
--- a/src/lib_base.cc
+++ b/src/lib_base.cc
@@ -312,6 +312,10 @@ end:
         }
     });
 
+    gcs.new_command("resetvar", "s", [](auto &cs, auto args, auto &) {
+        cs.reset_var(args[0].get_str());
+    });
+
     gcs.new_command("alias", "st", [](auto &cs, auto args, auto &) {
         cs.set_alias(args[0].get_str(), args[1]);
     });
diff --git a/tools/repl.cc b/tools/repl.cc
index 47c8704..cba5828 100644
--- a/tools/repl.cc
+++ b/tools/repl.cc
@@ -320,7 +320,7 @@ int main(int argc, char **argv) {
     cs::state gcs;
     gcs.init_libs();
 
-    gcs.new_command("//ivar", "$iiiN", [](auto &, auto args, auto &) {
+    gcs.new_command("//ivar", "$iiiN", [](auto &css, auto args, auto &) {
         auto *iv = args[0].get_ident()->get_ivar();
         auto nargs = args[4].get_int();
         if (nargs <= 1) {
@@ -334,7 +334,14 @@ int main(int argc, char **argv) {
             } else {
                 std::printf("%s = %d\n", iv->get_name().data(), val);
             }
-        } else if (nargs == 2) {
+            return;
+        }
+        if (iv->is_read_only()) {
+            throw cs::error{
+                css, "variable '%s' is read only", iv->get_name().data()
+            };
+        }
+        if (nargs == 2) {
             iv->set_value(args[1].get_int());
         } else if (nargs == 3) {
             iv->set_value(
@@ -348,7 +355,7 @@ int main(int argc, char **argv) {
         }
     });
 
-    gcs.new_command("//fvar", "$fN", [](auto &, auto args, auto &) {
+    gcs.new_command("//fvar", "$fN", [](auto &css, auto args, auto &) {
         auto *fv = args[0].get_ident()->get_fvar();
         auto nargs = args[2].get_int();
         if (nargs <= 1) {
@@ -358,12 +365,16 @@ int main(int argc, char **argv) {
             } else {
                 std::printf("%s = %.7g\n", fv->get_name().data(), val);
             }
+        } else if (fv->is_read_only()) {
+            throw cs::error{
+                css, "variable '%s' is read only", fv->get_name().data()
+            };
         } else {
             fv->set_value(args[1].get_float());
         }
     });
 
-    gcs.new_command("//svar", "$sN", [](auto &, auto args, auto &) {
+    gcs.new_command("//svar", "$sN", [](auto &css, auto args, auto &) {
         auto sv = args[0].get_ident()->get_svar();
         auto nargs = args[2].get_int();
         if (nargs <= 1) {
@@ -373,6 +384,10 @@ int main(int argc, char **argv) {
             } else {
                 std::printf("%s = [%s]\n", sv->get_name().data(), val.data());
             }
+        } else if (sv->is_read_only()) {
+            throw cs::error{
+                css, "variable '%s' is read only", sv->get_name().data()
+            };
         } else {
             sv->set_value(args[1].get_str());
         }