From ddb2f352cd7f7a5e18e1bff009e71aa9c02cee80 Mon Sep 17 00:00:00 2001
From: Jason Turner <jason@emptycrate.com>
Date: Thu, 17 Aug 2017 11:27:14 -0600
Subject: [PATCH] Initial simple application of constexpr to API

---
 include/chaiscript/chaiscript_defines.hpp     | 22 ++++-----
 include/chaiscript/chaiscript_threading.hpp   | 20 ++++----
 include/chaiscript/dispatchkit/any.hpp        |  2 +-
 include/chaiscript/dispatchkit/bind_first.hpp |  2 +-
 .../chaiscript/dispatchkit/bootstrap_stl.hpp  | 12 ++---
 .../dispatchkit/boxed_cast_helper.hpp         |  2 +-
 .../chaiscript/dispatchkit/boxed_number.hpp   | 20 ++++----
 include/chaiscript/dispatchkit/type_info.hpp  | 46 +++++++++---------
 .../language/chaiscript_algebraic.hpp         |  4 +-
 .../chaiscript/language/chaiscript_common.hpp |  8 ++--
 .../chaiscript/language/chaiscript_parser.hpp | 47 +++++++++----------
 .../chaiscript/language/chaiscript_tracer.hpp |  4 +-
 include/chaiscript/utility/static_string.hpp  |  6 +--
 13 files changed, 97 insertions(+), 98 deletions(-)

diff --git a/include/chaiscript/chaiscript_defines.hpp b/include/chaiscript/chaiscript_defines.hpp
index 4f8293d1..3754fc6a 100644
--- a/include/chaiscript/chaiscript_defines.hpp
+++ b/include/chaiscript/chaiscript_defines.hpp
@@ -75,13 +75,13 @@ static_assert(_MSC_FULL_VER >= 190024210, "Visual C++ 2015 Update 3 or later req
 #include <cmath>
 
 namespace chaiscript {
-  static const int version_major = 6;
-  static const int version_minor = 0;
-  static const int version_patch = 0;
+  constexpr static const int version_major = 6;
+  constexpr static const int version_minor = 0;
+  constexpr static const int version_patch = 0;
 
-  static const char *compiler_version = CHAISCRIPT_COMPILER_VERSION;
-  static const char *compiler_name = CHAISCRIPT_COMPILER_NAME;
-  static const bool debug_build = CHAISCRIPT_DEBUG;
+  constexpr static const char *compiler_version = CHAISCRIPT_COMPILER_VERSION;
+  constexpr static const char *compiler_name = CHAISCRIPT_COMPILER_NAME;
+  constexpr static const bool debug_build = CHAISCRIPT_DEBUG;
 
   template<typename B, typename D, typename ...Arg>
   inline std::shared_ptr<B> make_shared(Arg && ... arg)
@@ -104,17 +104,17 @@ namespace chaiscript {
   }
 
   struct Build_Info {
-    static int version_major() noexcept
+    constexpr static int version_major() noexcept
     {
       return chaiscript::version_major;
     }
 
-    static int version_minor() noexcept
+    constexpr static int version_minor() noexcept
     {
       return chaiscript::version_minor;
     }
 
-    static int version_patch() noexcept
+    constexpr static int version_patch() noexcept
     {
       return chaiscript::version_patch;
     }
@@ -144,7 +144,7 @@ namespace chaiscript {
       return chaiscript::compiler_name;
     }
 
-    static bool debug_build() noexcept
+    constexpr static bool debug_build() noexcept
     {
       return chaiscript::debug_build;
     }
@@ -152,7 +152,7 @@ namespace chaiscript {
 
 
   template<typename T>
-    auto parse_num(const char *t_str) noexcept -> typename std::enable_if<std::is_integral<T>::value, T>::type
+    constexpr auto parse_num(const char *t_str) noexcept -> typename std::enable_if<std::is_integral<T>::value, T>::type
     {
       T t = 0;
       for (char c = *t_str; (c = *t_str) != 0; ++t_str) {
diff --git a/include/chaiscript/chaiscript_threading.hpp b/include/chaiscript/chaiscript_threading.hpp
index ab455983..ce63df63 100644
--- a/include/chaiscript/chaiscript_threading.hpp
+++ b/include/chaiscript/chaiscript_threading.hpp
@@ -116,25 +116,25 @@ namespace chaiscript
       class unique_lock 
       {
         public:
-          explicit unique_lock(T &) noexcept {}
-          void lock() noexcept {}
-          void unlock() noexcept {}
+          constexpr explicit unique_lock(T &) noexcept {}
+          constexpr void lock() noexcept {}
+          constexpr void unlock() noexcept {}
       };
 
       template<typename T>
       class shared_lock 
       {
         public:
-          explicit shared_lock(T &) noexcept {}
-          void lock() noexcept {}
-          void unlock() noexcept {}
+          constexpr explicit shared_lock(T &) noexcept {}
+          constexpr void lock() noexcept {}
+          constexpr void unlock() noexcept {}
       };
 
       template<typename T>
       class lock_guard 
       {
         public:
-          explicit lock_guard(T &) noexcept {}
+          constexpr explicit lock_guard(T &) noexcept {}
       };
 
       class shared_mutex { };
@@ -146,16 +146,16 @@ namespace chaiscript
         class Thread_Storage
         {
           public:
-            explicit Thread_Storage() noexcept
+            constexpr explicit Thread_Storage() noexcept
             {
             }
 
-            inline T *operator->() const noexcept
+            constexpr inline T *operator->() const noexcept
             {
               return &obj;
             }
 
-            inline T &operator*() const noexcept
+            constexpr inline T &operator*() const noexcept
             {
               return obj;
             }
diff --git a/include/chaiscript/dispatchkit/any.hpp b/include/chaiscript/dispatchkit/any.hpp
index 1f010ea4..e9af7c36 100644
--- a/include/chaiscript/dispatchkit/any.hpp
+++ b/include/chaiscript/dispatchkit/any.hpp
@@ -34,7 +34,7 @@ namespace chaiscript {
       private:
         struct Data
         {
-          explicit Data(const std::type_info &t_type) noexcept
+          constexpr explicit Data(const std::type_info &t_type) noexcept
             : m_type(t_type)
           {
           }
diff --git a/include/chaiscript/dispatchkit/bind_first.hpp b/include/chaiscript/dispatchkit/bind_first.hpp
index 2a377d3d..8495e3c3 100644
--- a/include/chaiscript/dispatchkit/bind_first.hpp
+++ b/include/chaiscript/dispatchkit/bind_first.hpp
@@ -19,7 +19,7 @@ namespace chaiscript
   {
 
     template<typename T>
-      T* get_pointer(T *t) noexcept
+      constexpr T* get_pointer(T *t) noexcept
       {
         return t;
       }
diff --git a/include/chaiscript/dispatchkit/bootstrap_stl.hpp b/include/chaiscript/dispatchkit/bootstrap_stl.hpp
index 481d20df..df25c9ec 100644
--- a/include/chaiscript/dispatchkit/bootstrap_stl.hpp
+++ b/include/chaiscript/dispatchkit/bootstrap_stl.hpp
@@ -46,17 +46,17 @@ namespace chaiscript
         {
           typedef Container container_type;
 
-          Bidir_Range(Container &c)
+          constexpr Bidir_Range(Container &c)
             : m_begin(c.begin()), m_end(c.end())
           {
           }
 
-          bool empty() const noexcept
+          constexpr bool empty() const noexcept
           {
             return m_begin == m_end;
           }
 
-          void pop_front()
+          constexpr void pop_front()
           {
             if (empty())
             {
@@ -65,7 +65,7 @@ namespace chaiscript
             ++m_begin;
           }
 
-          void pop_back()
+          constexpr void pop_back()
           {
             if (empty())
             {
@@ -74,7 +74,7 @@ namespace chaiscript
             --m_end;
           }
 
-          decltype(auto) front() const
+          constexpr decltype(auto) front() const
           {
             if (empty())
             {
@@ -83,7 +83,7 @@ namespace chaiscript
             return (*m_begin);
           }
 
-          decltype(auto) back() const
+          constexpr decltype(auto) back() const
           {
             if (empty())
             {
diff --git a/include/chaiscript/dispatchkit/boxed_cast_helper.hpp b/include/chaiscript/dispatchkit/boxed_cast_helper.hpp
index b00dd045..834e4609 100644
--- a/include/chaiscript/dispatchkit/boxed_cast_helper.hpp
+++ b/include/chaiscript/dispatchkit/boxed_cast_helper.hpp
@@ -27,7 +27,7 @@ namespace chaiscript
     // Cast_Helper_Inner helper classes
 
     template<typename T>
-      T* throw_if_null(T *t)
+      constexpr T* throw_if_null(T *t)
       {
         if (t) { return t; }
         throw std::runtime_error("Attempted to dereference null Boxed_Value");
diff --git a/include/chaiscript/dispatchkit/boxed_number.hpp b/include/chaiscript/dispatchkit/boxed_number.hpp
index 084e91ad..7d22dddc 100644
--- a/include/chaiscript/dispatchkit/boxed_number.hpp
+++ b/include/chaiscript/dispatchkit/boxed_number.hpp
@@ -80,7 +80,7 @@ namespace chaiscript
       };
 
       template<typename T>
-      static inline void check_divide_by_zero(T t, typename std::enable_if<std::is_integral<T>::value>::type* = nullptr)
+      constexpr static inline void check_divide_by_zero(T t, typename std::enable_if<std::is_integral<T>::value>::type* = nullptr)
       {
 #ifndef CHAISCRIPT_NO_PROTECT_DIVIDEBYZERO
         if (t == 0) {
@@ -90,11 +90,11 @@ namespace chaiscript
       }
 
       template<typename T>
-      static inline void check_divide_by_zero(T, typename std::enable_if<std::is_floating_point<T>::value>::type* = nullptr) noexcept
+      constexpr static inline void check_divide_by_zero(T, typename std::enable_if<std::is_floating_point<T>::value>::type* = nullptr) noexcept
       {
       }
 
-      static Common_Types get_common_type(size_t t_size, bool t_signed) noexcept
+      constexpr static Common_Types get_common_type(size_t t_size, bool t_signed) noexcept
       {
         return   (t_size == 1 && t_signed)?(Common_Types::t_int8)
                 :(t_size == 1)?(Common_Types::t_uint8)
@@ -161,7 +161,7 @@ namespace chaiscript
       }
 
       template<typename T>
-      static bool boolean_go(Operators::Opers t_oper, const T &t, const T &u) noexcept
+      constexpr static bool boolean_go(Operators::Opers t_oper, const T &t, const T &u) noexcept
       {
         switch (t_oper)
         {
@@ -184,7 +184,7 @@ namespace chaiscript
       }
 
       template<typename T>
-      static void unary_go(Operators::Opers t_oper, T &t) noexcept
+      constexpr static void unary_go(Operators::Opers t_oper, T &t) noexcept
       {
         switch (t_oper)
         {
@@ -200,7 +200,7 @@ namespace chaiscript
       }
 
       template<typename T, typename U>
-      static void binary_go(Operators::Opers t_oper, T &t, const U &u)
+      constexpr static void binary_go(Operators::Opers t_oper, T &t, const U &u)
         noexcept(noexcept(check_divide_by_zero(u)))
       {
         switch (t_oper)
@@ -227,7 +227,7 @@ namespace chaiscript
       }
 
       template<typename T, typename U>
-      static void binary_int_go(Operators::Opers t_oper, T &t, const U &u) noexcept
+      constexpr static void binary_int_go(Operators::Opers t_oper, T &t, const U &u) noexcept
       {
         switch (t_oper)
         {
@@ -257,7 +257,7 @@ namespace chaiscript
 
 
       template<typename T>
-      static auto const_binary_int_go(Operators::Opers t_oper, T t, T u) 
+      constexpr static auto const_binary_int_go(Operators::Opers t_oper, T t, T u) 
         noexcept(noexcept(check_divide_by_zero(u)))
       {
         switch (t_oper)
@@ -282,7 +282,7 @@ namespace chaiscript
       }
 
       template<typename T>
-      static auto const_unary_go(Operators::Opers t_oper, T t) noexcept
+      constexpr static auto const_unary_go(Operators::Opers t_oper, T t) noexcept
       {
         switch (t_oper)
         {
@@ -297,7 +297,7 @@ namespace chaiscript
       }
 
       template<typename T>
-      static auto const_binary_go(Operators::Opers t_oper, T t, T u) 
+      constexpr static auto const_binary_go(Operators::Opers t_oper, T t, T u) 
         noexcept(noexcept(check_divide_by_zero(u)))
       {
         switch (t_oper)
diff --git a/include/chaiscript/dispatchkit/type_info.hpp b/include/chaiscript/dispatchkit/type_info.hpp
index 8199f872..f8fc868d 100644
--- a/include/chaiscript/dispatchkit/type_info.hpp
+++ b/include/chaiscript/dispatchkit/type_info.hpp
@@ -33,7 +33,7 @@ namespace chaiscript
   class Type_Info
   {
     public:
-      Type_Info(const bool t_is_const, const bool t_is_reference, const bool t_is_pointer, const bool t_is_void, 
+      constexpr Type_Info(const bool t_is_const, const bool t_is_reference, const bool t_is_pointer, const bool t_is_void, 
           const bool t_is_arithmetic, const std::type_info *t_ti, const std::type_info *t_bare_ti)
         : m_type_info(t_ti), m_bare_type_info(t_bare_ti),
           m_flags((static_cast<unsigned int>(t_is_const) << is_const_flag)
@@ -44,51 +44,51 @@ namespace chaiscript
       {
       }
 
-      Type_Info() = default;
+      constexpr Type_Info() = default;
 
-      bool operator<(const Type_Info &ti) const noexcept
+      constexpr bool operator<(const Type_Info &ti) const noexcept
       {
         return m_type_info < ti.m_type_info;
       }
 
-      bool operator!=(const Type_Info &ti) const noexcept
+      constexpr bool operator!=(const Type_Info &ti) const noexcept
       {
         return !(operator==(ti));
       }
 
-      bool operator!=(const std::type_info &ti) const noexcept
+      constexpr bool operator!=(const std::type_info &ti) const noexcept
       {
         return !(operator==(ti));
       }
 
-      bool operator==(const Type_Info &ti) const noexcept
+      constexpr bool operator==(const Type_Info &ti) const noexcept
       {
         return ti.m_type_info == m_type_info
            || *ti.m_type_info == *m_type_info;
       }
 
-      bool operator==(const std::type_info &ti) const noexcept
+      constexpr bool operator==(const std::type_info &ti) const noexcept
       {
         return !is_undef() && (*m_type_info) == ti;
       }
 
-      bool bare_equal(const Type_Info &ti) const noexcept
+      constexpr bool bare_equal(const Type_Info &ti) const noexcept
       {
         return ti.m_bare_type_info == m_bare_type_info
            || *ti.m_bare_type_info == *m_bare_type_info;
       }
 
-      bool bare_equal_type_info(const std::type_info &ti) const noexcept
+      constexpr bool bare_equal_type_info(const std::type_info &ti) const noexcept
       {
         return !is_undef() && (*m_bare_type_info) == ti;
       }
 
-      bool is_const() const noexcept { return (m_flags & (1 << is_const_flag)) != 0; }
-      bool is_reference() const noexcept { return (m_flags & (1 << is_reference_flag)) != 0; }
-      bool is_void() const noexcept { return (m_flags & (1 << is_void_flag)) != 0; }
-      bool is_arithmetic() const noexcept { return (m_flags & (1 << is_arithmetic_flag)) != 0; }
-      bool is_undef() const noexcept { return (m_flags & (1 << is_undef_flag)) != 0; }
-      bool is_pointer() const noexcept { return (m_flags & (1 << is_pointer_flag)) != 0; }
+      constexpr bool is_const() const noexcept { return (m_flags & (1 << is_const_flag)) != 0; }
+      constexpr bool is_reference() const noexcept { return (m_flags & (1 << is_reference_flag)) != 0; }
+      constexpr bool is_void() const noexcept { return (m_flags & (1 << is_void_flag)) != 0; }
+      constexpr bool is_arithmetic() const noexcept { return (m_flags & (1 << is_arithmetic_flag)) != 0; }
+      constexpr bool is_undef() const noexcept { return (m_flags & (1 << is_undef_flag)) != 0; }
+      constexpr bool is_pointer() const noexcept { return (m_flags & (1 << is_pointer_flag)) != 0; }
 
       const char * name() const noexcept
       {
@@ -110,7 +110,7 @@ namespace chaiscript
         }
       }
 
-      const std::type_info *bare_type_info() const noexcept
+      constexpr const std::type_info *bare_type_info() const noexcept
       {
         return m_bare_type_info;
       }
@@ -135,7 +135,7 @@ namespace chaiscript
     template<typename T>
       struct Get_Type_Info
       {
-        static Type_Info get() noexcept
+        constexpr static Type_Info get() noexcept
         {
           return Type_Info(std::is_const<typename std::remove_pointer<typename std::remove_reference<T>::type>::type>::value, 
               std::is_reference<T>::value, std::is_pointer<T>::value, 
@@ -152,7 +152,7 @@ namespace chaiscript
       {
 //        typedef T type;
 
-        static Type_Info get() noexcept
+        constexpr static Type_Info get() noexcept
         {
           return Type_Info(std::is_const<T>::value, std::is_reference<T>::value, std::is_pointer<T>::value, 
               std::is_void<T>::value,
@@ -170,7 +170,7 @@ namespace chaiscript
     template<typename T>
       struct Get_Type_Info<const std::shared_ptr<T> &>
       {
-        static Type_Info get() noexcept
+        constexpr static Type_Info get() noexcept
         {
           return Type_Info(std::is_const<T>::value, std::is_reference<T>::value, std::is_pointer<T>::value, 
               std::is_void<T>::value,
@@ -183,7 +183,7 @@ namespace chaiscript
     template<typename T>
       struct Get_Type_Info<std::reference_wrapper<T> >
       {
-        static Type_Info get() noexcept
+        constexpr static Type_Info get() noexcept
         {
           return Type_Info(std::is_const<T>::value, std::is_reference<T>::value, std::is_pointer<T>::value, 
               std::is_void<T>::value,
@@ -196,7 +196,7 @@ namespace chaiscript
     template<typename T>
       struct Get_Type_Info<const std::reference_wrapper<T> &>
       {
-        static Type_Info get() noexcept
+        constexpr static Type_Info get() noexcept
         {
           return Type_Info(std::is_const<T>::value, std::is_reference<T>::value, std::is_pointer<T>::value, 
               std::is_void<T>::value,
@@ -218,7 +218,7 @@ namespace chaiscript
   /// chaiscript::Type_Info ti = chaiscript::user_type(i);
   /// \endcode
   template<typename T>
-  Type_Info user_type(const T &/*t*/) noexcept
+  constexpr Type_Info user_type(const T &/*t*/) noexcept
   {
     return detail::Get_Type_Info<T>::get();
   }
@@ -233,7 +233,7 @@ namespace chaiscript
   /// chaiscript::Type_Info ti = chaiscript::user_type<int>();
   /// \endcode
   template<typename T>
-  Type_Info user_type() noexcept
+  constexpr Type_Info user_type() noexcept
   {
     return detail::Get_Type_Info<T>::get();
   }
diff --git a/include/chaiscript/language/chaiscript_algebraic.hpp b/include/chaiscript/language/chaiscript_algebraic.hpp
index 2030d061..5cf132dd 100644
--- a/include/chaiscript/language/chaiscript_algebraic.hpp
+++ b/include/chaiscript/language/chaiscript_algebraic.hpp
@@ -36,8 +36,8 @@ namespace chaiscript
       invalid
     };
 
-    static const char *to_string(Opers t_oper) noexcept {
-      static const char *opers[] = { 
+    constexpr static const char *to_string(Opers t_oper) noexcept {
+      constexpr const char *opers[] = { 
         "",
         "==", "<", ">", "<=", ">=", "!=",
         "",
diff --git a/include/chaiscript/language/chaiscript_common.hpp b/include/chaiscript/language/chaiscript_common.hpp
index 08d026aa..da25af22 100644
--- a/include/chaiscript/language/chaiscript_common.hpp
+++ b/include/chaiscript/language/chaiscript_common.hpp
@@ -81,8 +81,8 @@ namespace chaiscript
   namespace
   {
     /// Helper lookup to get the name of each node type
-    inline const char *ast_node_type_to_string(AST_Node_Type ast_node_type) noexcept {
-      static const char * const ast_node_types[] = { "Id", "Fun_Call", "Unused_Return_Fun_Call", "Arg_List", "Equation", "Var_Decl",
+    constexpr const char *ast_node_type_to_string(AST_Node_Type ast_node_type) noexcept {
+      constexpr const char * const ast_node_types[] = { "Id", "Fun_Call", "Unused_Return_Fun_Call", "Arg_List", "Equation", "Var_Decl",
                                     "Array_Call", "Dot_Access", 
                                     "Lambda", "Block", "Scopeless_Block", "Def", "While", "If", "For", "Ranged_For", "Inline_Array", "Inline_Map", "Return", "File", "Prefix", "Break", "Continue", "Map_Pair", "Value_Range",
                                     "Inline_Range", "Try", "Catch", "Finally", "Method", "Attr_Decl",
@@ -97,10 +97,10 @@ namespace chaiscript
     int line = 0;
     int column = 0;
 
-    File_Position(int t_file_line, int t_file_column) noexcept
+    constexpr File_Position(int t_file_line, int t_file_column) noexcept
       : line(t_file_line), column(t_file_column) { }
 
-    File_Position() noexcept = default;
+    constexpr File_Position() noexcept = default;
   };
 
   struct Parse_Location {
diff --git a/include/chaiscript/language/chaiscript_parser.hpp b/include/chaiscript/language/chaiscript_parser.hpp
index 64066718..7a24acb5 100644
--- a/include/chaiscript/language/chaiscript_parser.hpp
+++ b/include/chaiscript/language/chaiscript_parser.hpp
@@ -197,18 +197,18 @@ namespace chaiscript
         struct Array_View
         {
           template<std::size_t Len>
-            Array_View(const std::array<utility::Static_String, Len> &data) noexcept
-            : m_begin(&(*std::begin(data))),
-            m_end(&(*std::end(data)))
+            constexpr Array_View(const std::array<utility::Static_String, Len> &data) noexcept
+            : m_begin(&data.front()),
+              m_end(m_begin + Len)
             {
             }
 
-          auto begin() const noexcept
+          constexpr auto begin() const noexcept
           {
             return m_begin;
           }
 
-          auto end() const noexcept
+          constexpr auto end() const noexcept
           {
             return m_end;
           }
@@ -237,19 +237,19 @@ namespace chaiscript
           m_0, m_1, m_2, m_3, m_4, m_5, m_6, m_7, m_8, m_9, m_10, m_11
         }};
 
-        Operator_Matches() {}
+        constexpr Operator_Matches() noexcept {}
 
-        auto begin() const noexcept
+        constexpr auto begin() const noexcept
         {
           return all_data.begin();
         }
 
-        auto end() const noexcept
+        constexpr auto end() const noexcept
         {
           return all_data.end();
         }
 
-        decltype(auto) operator[](const std::size_t pos) const noexcept {
+        constexpr decltype(auto) operator[](const std::size_t pos) const noexcept {
           return (all_data[pos]);
         }
 
@@ -319,9 +319,9 @@ namespace chaiscript
 
       struct Position
       {
-        Position() = default;
+        constexpr Position() = default;
 
-        Position(std::string::const_iterator t_pos, std::string::const_iterator t_end) noexcept
+        constexpr Position(std::string::const_iterator t_pos, std::string::const_iterator t_end) noexcept
           : line(1), col(1), m_pos(t_pos), m_end(t_end), m_last_col(1)
         {
         }
@@ -344,7 +344,7 @@ namespace chaiscript
           return *this;
         }
 
-        Position &operator--() noexcept {
+        constexpr Position &operator--() noexcept {
           --m_pos;
           if (*m_pos == '\n') {
             --line;
@@ -355,12 +355,12 @@ namespace chaiscript
           return *this;
         }
 
-        Position &operator+=(size_t t_distance) noexcept {
+        constexpr Position &operator+=(size_t t_distance) noexcept {
           *this = (*this) + t_distance;
           return *this;
         }
 
-        Position operator+(size_t t_distance) const noexcept {
+        constexpr Position operator+(size_t t_distance) const noexcept {
           Position ret(*this);
           for (size_t i = 0; i < t_distance; ++i) {
             ++ret;
@@ -368,12 +368,12 @@ namespace chaiscript
           return ret;
         }
 
-        Position &operator-=(size_t t_distance) noexcept {
+        constexpr Position &operator-=(size_t t_distance) noexcept {
           *this = (*this) - t_distance;
           return *this;
         }
 
-        Position operator-(size_t t_distance) const noexcept {
+        constexpr Position operator-(size_t t_distance) const noexcept {
           Position ret(*this);
           for (size_t i = 0; i < t_distance; ++i) {
             --ret;
@@ -381,15 +381,15 @@ namespace chaiscript
           return ret;
         }
 
-        bool operator==(const Position &t_rhs) const noexcept {
+        constexpr bool operator==(const Position &t_rhs) const noexcept {
           return m_pos == t_rhs.m_pos;
         }
 
-        bool operator!=(const Position &t_rhs) const noexcept {
+        constexpr bool operator!=(const Position &t_rhs) const noexcept {
           return m_pos != t_rhs.m_pos;
         }
 
-        bool has_more() const noexcept {
+        constexpr bool has_more() const noexcept {
           return m_pos != m_end;
         }
 
@@ -397,10 +397,9 @@ namespace chaiscript
           return static_cast<size_t>(std::distance(m_pos, m_end));
         }
 
-        const char& operator*() const noexcept {
+        constexpr const char& operator*() const noexcept {
           if (m_pos == m_end) {
-            static const char ktmp ='\0';
-            return ktmp;
+            return ""[0];
           } else {
             return *m_pos;
           }
@@ -427,7 +426,7 @@ namespace chaiscript
         }
       }
 
-      public:
+    public:
       explicit ChaiScript_Parser(Tracer tracer = Tracer(), Optimizer optimizer=Optimizer())
         : m_tracer(std::move(tracer)),
           m_optimizer(std::move(optimizer))
@@ -451,7 +450,7 @@ namespace chaiscript
       ChaiScript_Parser &operator=(ChaiScript_Parser &&) = delete;
 
       /// test a char in an m_alphabet
-      bool char_in_alphabet(char c, detail::Alphabet a) const noexcept { return m_alphabet[a][static_cast<uint8_t>(c)]; }
+      constexpr bool char_in_alphabet(char c, detail::Alphabet a) const noexcept { return m_alphabet[a][static_cast<uint8_t>(c)]; }
 
       /// Prints the parsed ast_nodes as a tree
       void debug_print(const AST_Node &t, std::string prepend = "") const override {
diff --git a/include/chaiscript/language/chaiscript_tracer.hpp b/include/chaiscript/language/chaiscript_tracer.hpp
index 2cd82dcc..3774826b 100644
--- a/include/chaiscript/language/chaiscript_tracer.hpp
+++ b/include/chaiscript/language/chaiscript_tracer.hpp
@@ -14,7 +14,7 @@ namespace chaiscript {
     struct Noop_Tracer_Detail
     {
       template<typename T>
-        void trace(const chaiscript::detail::Dispatch_State &, const AST_Node_Impl<T> *) noexcept
+        constexpr void trace(const chaiscript::detail::Dispatch_State &, const AST_Node_Impl<T> *) noexcept
         {
         }
     };
@@ -23,7 +23,7 @@ namespace chaiscript {
       struct Tracer : T...
     {
       Tracer() = default;
-      explicit Tracer(T ... t)
+      constexpr explicit Tracer(T ... t)
         : T(std::move(t))...
       {
       }
diff --git a/include/chaiscript/utility/static_string.hpp b/include/chaiscript/utility/static_string.hpp
index 0f425032..fb63f28e 100644
--- a/include/chaiscript/utility/static_string.hpp
+++ b/include/chaiscript/utility/static_string.hpp
@@ -15,16 +15,16 @@ namespace chaiscript
     struct Static_String
     {
       template<size_t N>
-        Static_String(const char (&str)[N]) noexcept
+        constexpr Static_String(const char (&str)[N]) noexcept
         : m_size(N-1), data(&str[0])
         {
         }
 
-      size_t size() const noexcept {
+      constexpr size_t size() const noexcept {
         return m_size;
       }
 
-      const char *c_str() const noexcept {
+      constexpr const char *c_str() const noexcept {
         return data;
       }