diff --git a/include/xo/reader/expect_symbol_xs.hpp b/include/xo/reader/expect_symbol_xs.hpp
index 144bc3d0..40cb25b6 100644
--- a/include/xo/reader/expect_symbol_xs.hpp
+++ b/include/xo/reader/expect_symbol_xs.hpp
@@ -18,7 +18,9 @@ namespace xo {
         public:
             expect_symbol_xs();
 
-            static std::unique_ptr<expect_symbol_xs> expect_symbol_expression();
+            static std::unique_ptr<expect_symbol_xs> make();
+
+            static void start(exprstatestack * p_stack);
 
             virtual void on_symbol_token(const token_type & tk,
                                          exprstatestack * p_stack,
diff --git a/src/reader/define_xs.cpp b/src/reader/define_xs.cpp
index b813dc4d..6eab1bb7 100644
--- a/src/reader/define_xs.cpp
+++ b/src/reader/define_xs.cpp
@@ -98,7 +98,7 @@ namespace xo {
             if (this->defxs_type_ == defexprstatetype::def_0) {
                 this->defxs_type_ = defexprstatetype::def_1;
 
-                p_stack->push_exprstate(expect_symbol_xs::expect_symbol_expression());
+                expect_symbol_xs::start(p_stack);
             } else {
                 exprstate::on_def_token(tk, p_stack);
             }
diff --git a/src/reader/expect_formal_arglist_xs.cpp b/src/reader/expect_formal_arglist_xs.cpp
index 839a2f51..2c67c474 100644
--- a/src/reader/expect_formal_arglist_xs.cpp
+++ b/src/reader/expect_formal_arglist_xs.cpp
@@ -49,7 +49,7 @@ namespace xo {
                 this->farglxs_type_ = formalarglstatetype::argl_1a;
                 /* TODO: refactor to have setup method on each exprstate */
                 p_stack->push_exprstate(expect_formal_xs::make());
-                p_stack->push_exprstate(expect_symbol_xs::expect_symbol_expression());
+                expect_symbol_xs::start(p_stack);
             } else {
                 exprstate::on_leftparen_token(tk, p_stack, p_emit_expr);
             }
diff --git a/src/reader/expect_symbol_xs.cpp b/src/reader/expect_symbol_xs.cpp
index 84faeaa3..e6fd2bb7 100644
--- a/src/reader/expect_symbol_xs.cpp
+++ b/src/reader/expect_symbol_xs.cpp
@@ -8,10 +8,16 @@
 namespace xo {
     namespace scm {
         std::unique_ptr<expect_symbol_xs>
-        expect_symbol_xs::expect_symbol_expression() {
+        expect_symbol_xs::make() {
             return std::make_unique<expect_symbol_xs>(expect_symbol_xs());
         }
 
+        void
+        expect_symbol_xs::start(exprstatestack * p_stack)
+        {
+            p_stack->push_exprstate(expect_symbol_xs::make());
+        }
+
         expect_symbol_xs::expect_symbol_xs()
             : exprstate(exprstatetype::expect_symbol)
         {}