diff --git a/include/xo/reader/expect_expr_xs.hpp b/include/xo/reader/expect_expr_xs.hpp
index d826b5ae..a7cc997f 100644
--- a/include/xo/reader/expect_expr_xs.hpp
+++ b/include/xo/reader/expect_expr_xs.hpp
@@ -19,6 +19,9 @@ namespace xo {
 
             static std::unique_ptr<expect_expr_xs> expect_rhs_expression();
 
+            virtual void on_leftparen_token(const token_type & tk,
+                                            exprstatestack * p_stack,
+                                            rp<Expression> * p_emit_expr) override;
             virtual void on_f64_token(const token_type & tk,
                                       exprstatestack * p_stack,
                                       rp<Expression> * p_emit_expr) override;
diff --git a/include/xo/reader/exprstate.hpp b/include/xo/reader/exprstate.hpp
index 2ac8cf67..0997792e 100644
--- a/include/xo/reader/exprstate.hpp
+++ b/include/xo/reader/exprstate.hpp
@@ -70,11 +70,6 @@ namespace xo {
                 {}
             virtual ~exprstate() = default;
 
-#ifdef RELOCATED
-            static std::unique_ptr<exprstate> expect_rhs_expression() {
-                return std::make_unique<exprstate>(exprstate(exprstatetype::expect_rhs_expression));
-            }
-#endif
             static std::unique_ptr<exprstate> expect_symbol() {
                 return std::make_unique<exprstate>(exprstate(exprstatetype::expect_symbol));
             }
@@ -96,10 +91,6 @@ namespace xo {
             virtual bool admits_leftparen() const;
             /** truee iff this parsing state admits a rightparen ')' as next token **/
             virtual bool admits_rightparen() const;
-#ifdef OBSOLETE
-            /** true iff this parsing state admits a 64-bit floating point literal token **/
-            virtual bool admits_f64() const;
-#endif
 
             /** update exprstate in response to incoming token @p tk,
              *  forward instructions to parent parser
diff --git a/src/reader/expect_expr_xs.cpp b/src/reader/expect_expr_xs.cpp
index 78a69be2..be19b8bc 100644
--- a/src/reader/expect_expr_xs.cpp
+++ b/src/reader/expect_expr_xs.cpp
@@ -4,6 +4,7 @@
  */
 
 #include "expect_expr_xs.hpp"
+#include "paren_xs.hpp"
 #include "progress_xs.hpp"
 #include "xo/expression/Constant.hpp"
 
@@ -22,6 +23,21 @@ namespace xo {
             : exprstate(exprstatetype::expect_rhs_expression)
         {}
 
+        void
+        expect_expr_xs::on_leftparen_token(const token_type & /*tk*/,
+                                           exprstatestack * p_stack,
+                                           rp<Expression> * /*p_emit_expr*/)
+        {
+            constexpr bool c_debug_flag = true;
+            scope log(XO_DEBUG(c_debug_flag));
+
+            //constexpr const char * self_name = "exprstate::on_leftparen";
+
+            /* push lparen_0 to remember to look for subsequent rightparen. */
+            p_stack->push_exprstate(paren_xs::lparen_0());
+            p_stack->push_exprstate(expect_expr_xs::expect_rhs_expression());
+        }
+
         void
         expect_expr_xs::on_f64_token(const token_type & tk,
                                      exprstatestack * p_stack,
diff --git a/src/reader/exprstate.cpp b/src/reader/exprstate.cpp
index 8161f62e..b013feb1 100644
--- a/src/reader/exprstate.cpp
+++ b/src/reader/exprstate.cpp
@@ -196,14 +196,11 @@ namespace xo {
 
             case exprstatetype::defexpr:
             case exprstatetype::parenexpr:
-                /* unreachable - redirects to define_xs */
+            case exprstatetype::expect_rhs_expression:
+                /* unreachable - redirects to define_xs etc */
                 assert(false);
                 return false;
 
-            case exprstatetype::expect_rhs_expression:
-                /* can always begin non-toplevel expression with '(' */
-                return true;
-
             case exprstatetype::expect_type:
                 return false;
 
@@ -257,37 +254,6 @@ namespace xo {
             return false;
         }
 
-#ifdef OBSOLETE
-        bool
-        exprstate::admits_f64() const {
-            switch (exs_type_) {
-            case exprstatetype::expect_toplevel_expression_sequence:
-            case exprstatetype::defexpr:
-            case exprstatetype::parenexpr:
-            case exprstatetype::expect_rhs_expression:
-                /* unreachable - redirects to define_xs */
-                assert(false);
-                return false;
-
-            case exprstatetype::expect_symbol:
-            case exprstatetype::expect_type:
-                return false;
-
-            case exprstatetype::expr_progress:
-                /* unreachable */
-                assert(false);
-                return false;
-
-            case exprstatetype::invalid:
-            case exprstatetype::n_exprstatetype:
-                /* unreachable */
-                return false;
-            }
-
-            return false;
-        }
-#endif
-
         void
         exprstate::on_def_token(const token_type & tk,
                                 exprstatestack * /*p_stack*/)