diff --git a/Makefile b/Makefile
index bc602a3..95939c6 100644
--- a/Makefile
+++ b/Makefile
@@ -15,37 +15,17 @@
 #
 
 
-COMPILER         = -c++
-#COMPILER        = -clang
-OPTIMIZATION_OPT = -O1
-BASE_OPTIONS     = -pedantic-errors -Wall -Wextra -Werror -Wno-long-long
-OPTIONS          = $(BASE_OPTIONS) $(OPTIMIZATION_OPT)
-LINKER_OPT       = -L/usr/lib -lstdc++ -lm
-ASAN_OPT         = -g -fsanitize=address -fno-omit-frame-pointer
-MSAN_OPT         = -g -fsanitize=memory  -fno-omit-frame-pointer
-LSAN_OPT         = -g -fsanitize=leak    -fno-omit-frame-pointer
-
-BUILD_LIST+=exprtk_test
-BUILD_LIST+=exprtk_benchmark
-BUILD_LIST+=exprtk_simple_example_01
-BUILD_LIST+=exprtk_simple_example_02
-BUILD_LIST+=exprtk_simple_example_03
-BUILD_LIST+=exprtk_simple_example_04
-BUILD_LIST+=exprtk_simple_example_05
-BUILD_LIST+=exprtk_simple_example_06
-BUILD_LIST+=exprtk_simple_example_07
-BUILD_LIST+=exprtk_simple_example_08
-BUILD_LIST+=exprtk_simple_example_09
-BUILD_LIST+=exprtk_simple_example_10
-BUILD_LIST+=exprtk_simple_example_11
-BUILD_LIST+=exprtk_simple_example_12
-BUILD_LIST+=exprtk_simple_example_13
-BUILD_LIST+=exprtk_simple_example_14
-BUILD_LIST+=exprtk_simple_example_15
-BUILD_LIST+=exprtk_simple_example_16
-BUILD_LIST+=exprtk_simple_example_17
-BUILD_LIST+=exprtk_simple_example_18
-BUILD_LIST+=exprtk_simple_example_19
+COMPILER         := -c++
+#COMPILER        := -clang
+OPTIMIZATION_OPT := -O1
+BASE_OPTIONS     := -pedantic-errors -Wall -Wextra -Werror -Wno-long-long
+OPTIONS          := $(BASE_OPTIONS) $(OPTIMIZATION_OPT)
+LINKER_OPT       := -L/usr/lib -lstdc++ -lm
+ASAN_OPT         := -g -fsanitize=address -fno-omit-frame-pointer
+MSAN_OPT         := -g -fsanitize=memory  -fno-omit-frame-pointer
+LSAN_OPT         := -g -fsanitize=leak    -fno-omit-frame-pointer
+BUILD_SRC        := $(wildcard exprtk_*.cpp)
+BUILD_LIST       := $(BUILD_SRC:%.cpp=%)
 
 
 all: $(BUILD_LIST)
diff --git a/exprtk.hpp b/exprtk.hpp
index 2e62bf5..e25a5a3 100644
--- a/exprtk.hpp
+++ b/exprtk.hpp
@@ -733,7 +733,7 @@
                                       1.0E+013, 1.0E+014, 1.0E+015, 1.0E+016
                                     };
 
-     static const std::size_t pow10_size = sizeof(pow10) / sizeof(double);
+      static const std::size_t pow10_size = sizeof(pow10) / sizeof(double);
 
       namespace numeric
       {
@@ -23576,7 +23576,7 @@
       template <typename Type, std::size_t NumberOfParameters>
       struct parse_special_function_impl
       {
-         static inline expression_node_ptr process(parser<Type>& p,const details::operator_type opt_type)
+         static inline expression_node_ptr process(parser<Type>& p,const details::operator_type opt_type, const std::string& sf_name)
          {
             expression_node_ptr branch[NumberOfParameters];
             expression_node_ptr result  = error_node();
@@ -23592,7 +23592,7 @@
                p.set_error(
                     make_error(parser_error::e_syntax,
                                p.current_token(),
-                               "ERR126 - Expected '(' for special function",
+                               "ERR126 - Expected '(' for special function '" + sf_name + "'",
                                exprtk_error_location));
 
                return error_node();
@@ -23613,7 +23613,7 @@
                      p.set_error(
                           make_error(parser_error::e_syntax,
                                      p.current_token(),
-                                     "ERR127 - Expected ',' before next parameter of special function",
+                                     "ERR127 - Expected ',' before next parameter of special function '" + sf_name + "'",
                                      exprtk_error_location));
 
                      return p.error_node();
@@ -23622,7 +23622,15 @@
             }
 
             if (!p.token_is(token_t::e_rbracket))
+            {
+               p.set_error(
+                    make_error(parser_error::e_syntax,
+                               p.current_token(),
+                               "ERR128 - Invalid number of parameters for special function '" + sf_name + "'",
+                               exprtk_error_location));
+
                return p.error_node();
+            }
             else
                result = p.expression_generator_.special_function(opt_type,branch);
 
@@ -23634,30 +23642,32 @@
 
       inline expression_node_ptr parse_special_function()
       {
+         const std::string sf_name = current_token().value;
+
          // Expect: $fDD(expr0,expr1,expr2) or $fDD(expr0,expr1,expr2,expr3)
          if (
-              !details::is_digit(current_token().value[2]) ||
-              !details::is_digit(current_token().value[3])
+              !details::is_digit(sf_name[2]) ||
+              !details::is_digit(sf_name[3])
             )
          {
             set_error(
                make_error(parser_error::e_token,
                           current_token(),
-                          "ERR128 - Invalid special function[1]: " + current_token().value,
+                          "ERR129 - Invalid special function[1]: " + sf_name,
                           exprtk_error_location));
 
             return error_node();
          }
 
-         const int id = (current_token().value[2] - '0') * 10 +
-                        (current_token().value[3] - '0');
+         const int id = (sf_name[2] - '0') * 10 +
+                        (sf_name[3] - '0');
 
          if (id >= details::e_sffinal)
          {
             set_error(
                make_error(parser_error::e_token,
                           current_token(),
-                          "ERR129 - Invalid special function[2]: " + current_token().value,
+                          "ERR130 - Invalid special function[2]: " + sf_name,
                           exprtk_error_location));
 
             return error_node();
@@ -23669,8 +23679,8 @@
 
          switch (NumberOfParameters)
          {
-            case 3  : return parse_special_function_impl<T,3>::process((*this),opt_type);
-            case 4  : return parse_special_function_impl<T,4>::process((*this),opt_type);
+            case 3  : return parse_special_function_impl<T,3>::process((*this), opt_type, sf_name);
+            case 4  : return parse_special_function_impl<T,4>::process((*this), opt_type, sf_name);
             default : return error_node();
          }
       }
@@ -23689,7 +23699,7 @@
             set_error(
                make_error(parser_error::e_syntax,
                           current_token(),
-                          "ERR130 - Break call within a break call is not allowed",
+                          "ERR131 - Break call within a break call is not allowed",
                           exprtk_error_location));
 
             return error_node();
@@ -23712,7 +23722,7 @@
                   set_error(
                      make_error(parser_error::e_syntax,
                                 current_token(),
-                                "ERR131 - Failed to parse return expression for 'break' statement",
+                                "ERR132 - Failed to parse return expression for 'break' statement",
                                 exprtk_error_location));
 
                   return error_node();
@@ -23722,7 +23732,7 @@
                   set_error(
                      make_error(parser_error::e_syntax,
                                 current_token(),
-                                "ERR132 - Expected ']' at the completion of break's return expression",
+                                "ERR133 - Expected ']' at the completion of break's return expression",
                                 exprtk_error_location));
 
                   free_node(node_allocator_,return_expr);
@@ -23740,7 +23750,7 @@
             set_error(
                make_error(parser_error::e_syntax,
                           current_token(),
-                          "ERR133 - Invalid use of 'break', allowed only in the scope of a loop",
+                          "ERR134 - Invalid use of 'break', allowed only in the scope of a loop",
                           exprtk_error_location));
          }
 
@@ -23763,7 +23773,7 @@
             set_error(
                make_error(parser_error::e_syntax,
                           current_token(),
-                          "ERR134 - Invalid use of 'continue', allowed only in the scope of a loop",
+                          "ERR135 - Invalid use of 'continue', allowed only in the scope of a loop",
                           exprtk_error_location));
 
             return error_node();
@@ -23780,7 +23790,7 @@
             set_error(
                make_error(parser_error::e_syntax,
                           current_token(),
-                          "ERR135 - Expected '[' as part of vector size definition",
+                          "ERR136 - Expected '[' as part of vector size definition",
                           exprtk_error_location));
 
             return error_node();
@@ -23790,7 +23800,7 @@
             set_error(
                make_error(parser_error::e_syntax,
                           current_token(),
-                          "ERR136 - Failed to determine size of vector '" + vec_name + "'",
+                          "ERR137 - Failed to determine size of vector '" + vec_name + "'",
                           exprtk_error_location));
 
             return error_node();
@@ -23802,7 +23812,7 @@
             set_error(
                make_error(parser_error::e_syntax,
                           current_token(),
-                          "ERR137 - Expected a literal number as size of vector '" + vec_name + "'",
+                          "ERR138 - Expected a literal number as size of vector '" + vec_name + "'",
                           exprtk_error_location));
 
             return error_node();
@@ -23821,7 +23831,7 @@
             set_error(
                make_error(parser_error::e_syntax,
                           current_token(),
-                          "ERR138 - Invalid vector size. Must be an integer greater than zero, size: " +
+                          "ERR139 - Invalid vector size. Must be an integer greater than zero, size: " +
                           details::to_str(details::numeric::to_int32(vector_size)),
                           exprtk_error_location));
 
@@ -23841,7 +23851,7 @@
             set_error(
                make_error(parser_error::e_syntax,
                           current_token(),
-                          "ERR139 - Expected ']' as part of vector size definition",
+                          "ERR140 - Expected ']' as part of vector size definition",
                           exprtk_error_location));
 
             return error_node();
@@ -23853,7 +23863,7 @@
                set_error(
                   make_error(parser_error::e_syntax,
                              current_token(),
-                             "ERR140 - Expected ':=' as part of vector definition",
+                             "ERR141 - Expected ':=' as part of vector definition",
                              exprtk_error_location));
 
                return error_node();
@@ -23867,7 +23877,7 @@
                   set_error(
                      make_error(parser_error::e_syntax,
                                 current_token(),
-                                "ERR141 - Failed to parse single vector initialiser",
+                                "ERR142 - Failed to parse single vector initialiser",
                                 exprtk_error_location));
 
                   return error_node();
@@ -23880,7 +23890,7 @@
                   set_error(
                      make_error(parser_error::e_syntax,
                                 current_token(),
-                                "ERR142 - Expected ']' to close single value vector initialiser",
+                                "ERR143 - Expected ']' to close single value vector initialiser",
                                 exprtk_error_location));
 
                   return error_node();
@@ -23927,7 +23937,7 @@
                      set_error(
                         make_error(parser_error::e_syntax,
                                    current_token(),
-                                   "ERR143 - Expected '{' as part of vector initialiser list",
+                                   "ERR144 - Expected '{' as part of vector initialiser list",
                                    exprtk_error_location));
 
                      return error_node();
@@ -23947,7 +23957,7 @@
                      set_error(
                         make_error(parser_error::e_syntax,
                                    current_token(),
-                                   "ERR144 - Expected '{' as part of vector initialiser list",
+                                   "ERR145 - Expected '{' as part of vector initialiser list",
                                    exprtk_error_location));
 
                      return error_node();
@@ -23965,7 +23975,7 @@
                      set_error(
                         make_error(parser_error::e_syntax,
                                    current_token(),
-                                   "ERR145 - Expected ',' between vector initialisers",
+                                   "ERR146 - Expected ',' between vector initialisers",
                                    exprtk_error_location));
 
                      return error_node();
@@ -23987,7 +23997,7 @@
                   set_error(
                      make_error(parser_error::e_syntax,
                                 current_token(),
-                                "ERR146 - Expected ';' at end of vector definition",
+                                "ERR147 - Expected ';' at end of vector definition",
                                 exprtk_error_location));
 
                   return error_node();
@@ -23999,7 +24009,7 @@
                set_error(
                   make_error(parser_error::e_syntax,
                              current_token(),
-                             "ERR147 - Initialiser list larger than the number of elements in the vector: '" + vec_name + "'",
+                             "ERR148 - Initialiser list larger than the number of elements in the vector: '" + vec_name + "'",
                              exprtk_error_location));
 
                return error_node();
@@ -24019,7 +24029,7 @@
                set_error(
                   make_error(parser_error::e_syntax,
                              current_token(),
-                             "ERR148 - Illegal redefinition of local vector: '" + vec_name + "'",
+                             "ERR149 - Illegal redefinition of local vector: '" + vec_name + "'",
                              exprtk_error_location));
 
                return error_node();
@@ -24053,7 +24063,7 @@
                set_error(
                   make_error(parser_error::e_syntax,
                              current_token(),
-                             "ERR149 - Failed to add new local vector '" + vec_name + "' to SEM",
+                             "ERR150 - Failed to add new local vector '" + vec_name + "' to SEM",
                              exprtk_error_location));
 
                sem_.free_element(nse);
@@ -24108,7 +24118,7 @@
                set_error(
                   make_error(parser_error::e_syntax,
                              current_token(),
-                             "ERR150 - Illegal redefinition of local variable: '" + str_name + "'",
+                             "ERR151 - Illegal redefinition of local variable: '" + str_name + "'",
                              exprtk_error_location));
 
                free_node(node_allocator_,initialisation_expression);
@@ -24140,7 +24150,7 @@
                set_error(
                   make_error(parser_error::e_syntax,
                              current_token(),
-                             "ERR151 - Failed to add new local string variable '" + str_name + "' to SEM",
+                             "ERR152 - Failed to add new local string variable '" + str_name + "' to SEM",
                              exprtk_error_location));
 
                free_node(node_allocator_,initialisation_expression);
@@ -24186,7 +24196,7 @@
             set_error(
                make_error(parser_error::e_syntax,
                           current_token(),
-                          "ERR152 - Illegal variable definition",
+                          "ERR153 - Illegal variable definition",
                           exprtk_error_location));
 
             return error_node();
@@ -24207,7 +24217,7 @@
             set_error(
                make_error(parser_error::e_syntax,
                           current_token(),
-                          "ERR153 - Expected a symbol for variable definition",
+                          "ERR154 - Expected a symbol for variable definition",
                           exprtk_error_location));
 
             return error_node();
@@ -24217,7 +24227,7 @@
             set_error(
                make_error(parser_error::e_syntax,
                           current_token(),
-                          "ERR154 - Illegal redefinition of reserved keyword: '" + var_name + "'",
+                          "ERR155 - Illegal redefinition of reserved keyword: '" + var_name + "'",
                           exprtk_error_location));
 
             return error_node();
@@ -24227,7 +24237,7 @@
             set_error(
                make_error(parser_error::e_syntax,
                           current_token(),
-                          "ERR155 - Illegal redefinition of variable '" + var_name + "'",
+                          "ERR156 - Illegal redefinition of variable '" + var_name + "'",
                           exprtk_error_location));
 
             return error_node();
@@ -24237,7 +24247,7 @@
             set_error(
                make_error(parser_error::e_syntax,
                           current_token(),
-                          "ERR156 - Illegal redefinition of local variable: '" + var_name + "'",
+                          "ERR157 - Illegal redefinition of local variable: '" + var_name + "'",
                           exprtk_error_location));
 
             return error_node();
@@ -24257,7 +24267,7 @@
                set_error(
                   make_error(parser_error::e_syntax,
                              current_token(),
-                             "ERR157 - Failed to parse initialisation expression",
+                             "ERR158 - Failed to parse initialisation expression",
                              exprtk_error_location));
 
                return error_node();
@@ -24275,7 +24285,7 @@
                set_error(
                   make_error(parser_error::e_syntax,
                              current_token(),
-                             "ERR158 - Expected ';' after variable definition",
+                             "ERR159 - Expected ';' after variable definition",
                              exprtk_error_location));
 
                free_node(node_allocator_,initialisation_expression);
@@ -24303,7 +24313,7 @@
                set_error(
                   make_error(parser_error::e_syntax,
                              current_token(),
-                             "ERR159 - Illegal redefinition of local variable: '" + var_name + "'",
+                             "ERR160 - Illegal redefinition of local variable: '" + var_name + "'",
                              exprtk_error_location));
 
                free_node(node_allocator_, initialisation_expression);
@@ -24335,7 +24345,7 @@
                set_error(
                   make_error(parser_error::e_syntax,
                              current_token(),
-                             "ERR160 - Failed to add new local variable '" + var_name + "' to SEM",
+                             "ERR161 - Failed to add new local variable '" + var_name + "' to SEM",
                              exprtk_error_location));
 
                free_node(node_allocator_, initialisation_expression);
@@ -24372,7 +24382,7 @@
             set_error(
                make_error(parser_error::e_syntax,
                           current_token(),
-                          "ERR161 - Expected a '{}' for uninitialised var definition",
+                          "ERR162 - Expected a '{}' for uninitialised var definition",
                           exprtk_error_location));
 
             return error_node();
@@ -24382,7 +24392,7 @@
             set_error(
                make_error(parser_error::e_syntax,
                           current_token(),
-                          "ERR162 - Expected ';' after uninitialised variable definition",
+                          "ERR163 - Expected ';' after uninitialised variable definition",
                           exprtk_error_location));
 
             return error_node();
@@ -24399,7 +24409,7 @@
                set_error(
                   make_error(parser_error::e_syntax,
                              current_token(),
-                             "ERR163 - Illegal redefinition of local variable: '" + var_name + "'",
+                             "ERR164 - Illegal redefinition of local variable: '" + var_name + "'",
                              exprtk_error_location));
 
                return error_node();
@@ -24429,7 +24439,7 @@
                set_error(
                   make_error(parser_error::e_syntax,
                              current_token(),
-                             "ERR164 - Failed to add new local variable '" + var_name + "' to SEM",
+                             "ERR165 - Failed to add new local variable '" + var_name + "' to SEM",
                              exprtk_error_location));
 
                sem_.free_element(nse);
@@ -24462,7 +24472,7 @@
             set_error(
                make_error(parser_error::e_syntax,
                           current_token(),
-                          "ERR165 - Expected '(' at start of swap statement",
+                          "ERR166 - Expected '(' at start of swap statement",
                           exprtk_error_location));
 
             return error_node();
@@ -24481,7 +24491,7 @@
             set_error(
                make_error(parser_error::e_syntax,
                           current_token(),
-                          "ERR166 - Expected a symbol for variable or vector element definition",
+                          "ERR167 - Expected a symbol for variable or vector element definition",
                           exprtk_error_location));
 
             return error_node();
@@ -24493,7 +24503,7 @@
                set_error(
                   make_error(parser_error::e_syntax,
                              current_token(),
-                             "ERR167 - First parameter to swap is an invalid vector element: '" + var0_name + "'",
+                             "ERR168 - First parameter to swap is an invalid vector element: '" + var0_name + "'",
                              exprtk_error_location));
 
                return error_node();
@@ -24526,7 +24536,7 @@
                set_error(
                   make_error(parser_error::e_syntax,
                              current_token(),
-                             "ERR168 - First parameter to swap is an invalid variable: '" + var0_name + "'",
+                             "ERR169 - First parameter to swap is an invalid variable: '" + var0_name + "'",
                              exprtk_error_location));
 
                return error_node();
@@ -24540,7 +24550,7 @@
             set_error(
                 make_error(parser_error::e_syntax,
                            current_token(),
-                           "ERR169 - Expected ',' between parameters to swap",
+                           "ERR170 - Expected ',' between parameters to swap",
                            exprtk_error_location));
 
             if (variable0_generated)
@@ -24558,7 +24568,7 @@
             set_error(
                make_error(parser_error::e_syntax,
                           current_token(),
-                          "ERR170 - Expected a symbol for variable or vector element definition",
+                          "ERR171 - Expected a symbol for variable or vector element definition",
                           exprtk_error_location));
 
             if (variable0_generated)
@@ -24575,7 +24585,7 @@
                set_error(
                   make_error(parser_error::e_syntax,
                              current_token(),
-                             "ERR171 - Second parameter to swap is an invalid vector element: '" + var1_name + "'",
+                             "ERR172 - Second parameter to swap is an invalid vector element: '" + var1_name + "'",
                              exprtk_error_location));
 
                if (variable0_generated)
@@ -24613,7 +24623,7 @@
                set_error(
                   make_error(parser_error::e_syntax,
                              current_token(),
-                             "ERR172 - Second parameter to swap is an invalid variable: '" + var1_name + "'",
+                             "ERR173 - Second parameter to swap is an invalid variable: '" + var1_name + "'",
                              exprtk_error_location));
 
                if (variable0_generated)
@@ -24632,7 +24642,7 @@
             set_error(
                make_error(parser_error::e_syntax,
                           current_token(),
-                          "ERR173 - Expected ')' at end of swap statement",
+                          "ERR174 - Expected ')' at end of swap statement",
                           exprtk_error_location));
 
             if (variable0_generated)
@@ -24689,7 +24699,7 @@
             set_error(
                make_error(parser_error::e_syntax,
                           current_token(),
-                          "ERR174 - Return call within a return call is not allowed",
+                          "ERR175 - Return call within a return call is not allowed",
                           exprtk_error_location));
 
             return error_node();
@@ -24713,7 +24723,7 @@
             set_error(
                make_error(parser_error::e_syntax,
                           current_token(),
-                          "ERR175 - Expected '[' at start of return statement",
+                          "ERR176 - Expected '[' at start of return statement",
                           exprtk_error_location));
 
             return error_node();
@@ -24736,7 +24746,7 @@
                   set_error(
                      make_error(parser_error::e_syntax,
                                 current_token(),
-                                "ERR176 - Expected ',' between values during call to return",
+                                "ERR177 - Expected ',' between values during call to return",
                                 exprtk_error_location));
 
                   return error_node();
@@ -24748,7 +24758,7 @@
             set_error(
                make_error(parser_error::e_syntax,
                           current_token(),
-                          "ERR177 - Zero parameter return statement not allowed",
+                          "ERR178 - Zero parameter return statement not allowed",
                           exprtk_error_location));
 
             return error_node();
@@ -24763,7 +24773,7 @@
                set_error(
                   make_error(parser_error::e_syntax,
                              prev_token,
-                             "ERR178 - Invalid ']' found during return call",
+                             "ERR179 - Invalid ']' found during return call",
                              exprtk_error_location));
 
                return error_node();
@@ -24816,7 +24826,7 @@
                set_error(
                   make_error(parser_error::e_syntax,
                              current_token(),
-                             "ERR179 - Invalid sequence of variable '"+ symbol + "' and bracket",
+                             "ERR180 - Invalid sequence of variable '"+ symbol + "' and bracket",
                              exprtk_error_location));
 
                return false;
@@ -24864,7 +24874,7 @@
                set_error(
                   make_error(parser_error::e_syntax,
                              current_token(),
-                             "ERR180 - Invalid sequence of brackets",
+                             "ERR181 - Invalid sequence of brackets",
                              exprtk_error_location));
 
                return false;
@@ -24961,7 +24971,7 @@
                   set_error(
                      make_error(parser_error::e_syntax,
                                 current_token(),
-                                "ERR181 - Failed to generate node for function: '" + symbol + "'",
+                                "ERR182 - Failed to generate node for function: '" + symbol + "'",
                                 exprtk_error_location));
 
                   return error_node();
@@ -24987,7 +24997,7 @@
                   set_error(
                      make_error(parser_error::e_syntax,
                                 current_token(),
-                                "ERR182 - Failed to generate node for vararg function: '" + symbol + "'",
+                                "ERR183 - Failed to generate node for vararg function: '" + symbol + "'",
                                 exprtk_error_location));
 
                   return error_node();
@@ -25013,7 +25023,7 @@
                   set_error(
                      make_error(parser_error::e_syntax,
                                 current_token(),
-                                "ERR183 - Failed to generate node for generic function: '" + symbol + "'",
+                                "ERR184 - Failed to generate node for generic function: '" + symbol + "'",
                                 exprtk_error_location));
 
                   return error_node();
@@ -25040,7 +25050,7 @@
                   set_error(
                      make_error(parser_error::e_syntax,
                                 current_token(),
-                                "ERR184 - Failed to generate node for string function: '" + symbol + "'",
+                                "ERR185 - Failed to generate node for string function: '" + symbol + "'",
                                 exprtk_error_location));
 
                   return error_node();
@@ -25066,7 +25076,7 @@
                   set_error(
                      make_error(parser_error::e_syntax,
                                 current_token(),
-                                "ERR185 - Invalid use of reserved symbol '" + symbol + "'",
+                                "ERR186 - Invalid use of reserved symbol '" + symbol + "'",
                                 exprtk_error_location));
 
                   return error_node();
@@ -25129,7 +25139,7 @@
                   set_error(
                      make_error(parser_error::e_symtab,
                                 current_token(),
-                                "ERR186 - Failed to create variable: '" + symbol + "'" +
+                                "ERR187 - Failed to create variable: '" + symbol + "'" +
                                 (error_message.empty() ? "" : " - " + error_message),
                                 exprtk_error_location));
 
@@ -25149,7 +25159,7 @@
                   set_error(
                      make_error(parser_error::e_symtab,
                                 current_token(),
-                                "ERR187 - Failed to resolve symbol: '" + symbol + "'" +
+                                "ERR188 - Failed to resolve symbol: '" + symbol + "'" +
                                 (error_message.empty() ? "" : " - " + error_message),
                                 exprtk_error_location));
                }
@@ -25161,7 +25171,7 @@
          set_error(
             make_error(parser_error::e_syntax,
                        current_token(),
-                       "ERR188 - Undefined symbol: '" + symbol + "'",
+                       "ERR189 - Undefined symbol: '" + symbol + "'",
                        exprtk_error_location));
 
          return error_node();
@@ -25268,7 +25278,7 @@
             set_error(
                make_error(parser_error::e_symtab,
                           current_token(),
-                          "ERR189 - Variable or function detected, yet symbol-table is invalid, Symbol: " + current_token().value,
+                          "ERR190 - Variable or function detected, yet symbol-table is invalid, Symbol: " + current_token().value,
                           exprtk_error_location));
 
             return error_node();
@@ -25292,7 +25302,7 @@
                   set_error(
                      make_error(parser_error::e_numeric,
                                 current_token(),
-                                "ERR190 - Failed generate node for scalar: '" + current_token().value + "'",
+                                "ERR191 - Failed generate node for scalar: '" + current_token().value + "'",
                                 exprtk_error_location));
 
                   return error_node();
@@ -25306,7 +25316,7 @@
                set_error(
                   make_error(parser_error::e_numeric,
                              current_token(),
-                             "ERR191 - Failed to convert '" + current_token().value + "' to a number",
+                             "ERR192 - Failed to convert '" + current_token().value + "' to a number",
                              exprtk_error_location));
 
                return error_node();
@@ -25333,7 +25343,7 @@
                set_error(
                   make_error(parser_error::e_syntax,
                              current_token(),
-                             "ERR192 - Expected ')' instead of: '" + current_token().value + "'",
+                             "ERR193 - Expected ')' instead of: '" + current_token().value + "'",
                              exprtk_error_location));
 
                free_node(node_allocator_,branch);
@@ -25358,7 +25368,7 @@
                set_error(
                   make_error(parser_error::e_syntax,
                              current_token(),
-                             "ERR193 - Expected ']' instead of: '" + current_token().value + "'",
+                             "ERR194 - Expected ']' instead of: '" + current_token().value + "'",
                              exprtk_error_location));
 
                free_node(node_allocator_,branch);
@@ -25383,7 +25393,7 @@
                set_error(
                   make_error(parser_error::e_syntax,
                              current_token(),
-                             "ERR194 - Expected '}' instead of: '" + current_token().value + "'",
+                             "ERR195 - Expected '}' instead of: '" + current_token().value + "'",
                              exprtk_error_location));
 
                free_node(node_allocator_,branch);
@@ -25423,7 +25433,7 @@
             set_error(
                make_error(parser_error::e_syntax,
                           current_token(),
-                          "ERR195 - Premature end of expression[1]",
+                          "ERR196 - Premature end of expression[1]",
                           exprtk_error_location));
 
             return error_node();
@@ -25433,7 +25443,7 @@
             set_error(
                make_error(parser_error::e_syntax,
                           current_token(),
-                          "ERR196 - Premature end of expression[2]",
+                          "ERR197 - Premature end of expression[2]",
                           exprtk_error_location));
 
             return error_node();
@@ -26126,19 +26136,19 @@
                return false;
             else
                return (
-                        (details::e_lt     == operation) ||
-                        (details::e_lte    == operation) ||
-                        (details::e_gt     == operation) ||
-                        (details::e_gte    == operation) ||
-                        (details::e_eq     == operation) ||
-                        (details::e_ne     == operation) ||
-                        (details::e_equal  == operation) ||
-                        (details::e_and    == operation) ||
-                        (details::e_nand   == operation) ||
-                        (details::  e_or   == operation) ||
-                        (details:: e_nor   == operation) ||
-                        (details:: e_xor   == operation) ||
-                        (details::e_xnor   == operation)
+                        (details::e_lt    == operation) ||
+                        (details::e_lte   == operation) ||
+                        (details::e_gt    == operation) ||
+                        (details::e_gte   == operation) ||
+                        (details::e_eq    == operation) ||
+                        (details::e_ne    == operation) ||
+                        (details::e_equal == operation) ||
+                        (details::e_and   == operation) ||
+                        (details::e_nand  == operation) ||
+                        (details::  e_or  == operation) ||
+                        (details:: e_nor  == operation) ||
+                        (details:: e_xor  == operation) ||
+                        (details::e_xnor  == operation)
                       );
          }
 
diff --git a/readme.txt b/readme.txt
index a819125..af6df6d 100644
--- a/readme.txt
+++ b/readme.txt
@@ -3710,7 +3710,7 @@
 
    if (exprtk::collect_variables(expression, variable_list))
    {
-      for (auto var : variable_list)
+      for (const auto& var : variable_list)
       {
          ...
       }
@@ -3734,7 +3734,7 @@
 
    if (exprtk::collect_functions(expression, function_list))
    {
-      for (auto func : function_list)
+      for (const auto& func : function_list)
       {
          ...
       }
@@ -3779,7 +3779,7 @@
 
    if (exprtk::collect_functions(expression, sym_tab, function_list))
    {
-      for (auto func : function_list)
+      for (const auto& func : function_list)
       {
          ...
       }
@@ -3910,7 +3910,7 @@
    // Differentiate expression at value of x = 12.3 using a reference
    // to the x variable
    x = T(12.3);
-   T derivative1 = exprtk::derivative(expression,x);
+   T derivative1 = exprtk::derivative(expression, x);
 
    // Differentiate expression where value x = 45.6 using name
    // of the x variable
@@ -3988,7 +3988,7 @@
    // Third derivative of expression where value of x = 12.3 using a
    // reference to the x variable
    x = T(12.3);
-   T derivative1 = exprtk::third_derivative(expression,x);
+   T derivative1 = exprtk::third_derivative(expression, x);
 
    // Third derivative of expression where value of x = 45.6 using
    // name of the x variable