C++ Mathematical Expression Library (ExprTk) http://www.partow.net/programming/exprtk/index.html

exprtk_test.cpp

@@ -32,7 +32,7 @@
 typedef double numeric_type;
 typedef std::pair<std::string,numeric_type> test_t;
 
-static const test_t test_list[] =
+static const test_t global_test_list[] =
                   {
                     // Note: Each of following tests must compile down
                     // to a single literal node.
@@ -1061,7 +1061,7 @@ static const test_t test_list[] =
                     test_t("if (1 > 2) { 1+2; 3;} else if (1 > 2) {1+2; 4;} == null",1.0)
                   };
 
-static const std::size_t test_list_size = sizeof(test_list) / sizeof(test_t);
+static const std::size_t global_test_list_size = sizeof(global_test_list) / sizeof(test_t);
 
 template <typename T>
 inline bool not_equal_impl(const T& t1,
@@ -1165,9 +1165,9 @@ inline bool run_test00()
    for (std::size_t r = 0; r < rounds; ++r)
    {
       bool result = true;
-      for (std::size_t i = 0; i < test_list_size; ++i)
+      for (std::size_t i = 0; i < global_test_list_size; ++i)
       {
-         if (!test_expression<T>(test_list[i].first,T(test_list[i].second)))
+         if (!test_expression<T>(global_test_list[i].first,T(global_test_list[i].second)))
          {
             result = false;
          }
@@ -1576,7 +1576,14 @@ inline bool run_test01()
                                 test_xy<T>("for(var i := 0; (i < 10) and (i != y); i+=2) { x += i; }; x;" ,T(1),T(20),T(21)),
                                 test_xy<T>("for(var i := 0; (i < 10) and (i != y);) { x += i; i+=2; }; x;",T(1),T(20),T(21)),
                                 test_xy<T>("for(var i := 0; (i < y); i += 1) { if (i <= (y / 2)) x += i; else break; }; x;" ,T(0),T(10),T(15)),
-                                test_xy<T>("for(var i := 0; (i < y); i += 1) { if (i <= (y / 2)) continue; else x += i; }; x;" ,T(0),T(10),T(30))
+                                test_xy<T>("for(var i := 0; (i < y); i += 1) { if (i <= (y / 2)) continue; else x += i; }; x;" ,T(0),T(10),T(30)),
+                                test_xy<T>("var a := 2; (0 * a) == 0",T(0),T(0),T(1)),
+                                test_xy<T>("var a := 2; (0 / a) == 0",T(0),T(0),T(1)),
+                                test_xy<T>("var a := 2; (a * 0) == 0",T(0),T(0),T(1)),
+                                test_xy<T>("var a := 2; (a / 1) == a",T(0),T(0),T(1)),
+                                test_xy<T>("var a := 2; (0 + a) == a",T(0),T(0),T(1)),
+                                test_xy<T>("var a := 2; (a + 0) == a",T(0),T(0),T(1)),
+                                test_xy<T>("var a := 2; (1 * a) == a",T(0),T(0),T(1))
                               };
 
       static const std::size_t test_list_size = sizeof(test_list) / sizeof(test_xy<T>);
@@ -2270,12 +2277,42 @@ inline bool run_test02()
                              test_ab<T>("'a\\'\\\\b' == a" ,"a'\\b","",T(1.0)),
                              test_ab<T>("'a\\\\\\'b' == a" ,"a\\'b","",T(1.0)),
                              test_ab<T>("'a\\'\\\\\\\\b' == a" ,"a'\\\\b","",T(1.0)),
-                             test_ab<T>("'a\\0x30\\'\\0x31\\\\\\0x32b' == a" ,"a0'1\\2b","",T(1.0))
+                             test_ab<T>("'a\\0x30\\'\\0x31\\\\\\0x32b' == a" ,"a0'1\\2b","",T(1.0)),
+
+                             test_ab<T>("var x := 3; x > 2 and 'abc' like  '*bc'"   ,"","",T(1.0)),
+                             test_ab<T>("var x := 3; x > 2 and 'abc' ilike '*Bc'"   ,"","",T(1.0)),
+                             test_ab<T>("var x := 3; x > 2 and 'abc' in '123abc123'","","",T(1.0)),
+
+                             test_ab<T>("var x := 3; var s := 'abc'; x > 2 and s like  '*bc'"   ,"","",T(1.0)),
+                             test_ab<T>("var x := 3; var s := 'abc'; x > 2 and s ilike '*Bc'"   ,"","",T(1.0)),
+                             test_ab<T>("var x := 3; var s := 'abc'; x > 2 and s in '123abc123'","","",T(1.0)),
+
+                             test_ab<T>("var x := 3; var s := 'abc'; var t := '*bc'; x > 2 and s like  t"   ,"","",T(1.0)),
+                             test_ab<T>("var x := 3; var s := 'abc'; var t := '*Bc'; x > 2 and s ilike t"   ,"","",T(1.0)),
+                             test_ab<T>("var x := 3; var s := 'abc'; var t := '123abc123'; x > 2 and s in t","","",T(1.0)),
+
+                             test_ab<T>("var x := 3; x > 2 and a like  '*bc'"   ,"abc","",T(1.0)),
+                             test_ab<T>("var x := 3; x > 2 and a ilike '*Bc'"   ,"abc","",T(1.0)),
+                             test_ab<T>("var x := 3; x > 2 and a in '123abc123'","abc","",T(1.0)),
+
+                             test_ab<T>("var x := 3; x > 2 and a like b ","abc","*bc",T(1.0)),
+                             test_ab<T>("var x := 3; x > 2 and a ilike b","abc","*Bc",T(1.0)),
+                             test_ab<T>("var x := 3; x > 2 and a in b   ","abc","123abc123",T(1.0)),
+
+                             test_ab<T>("a[] > 2 and a like  '*bc'"   ,"abc","",T(1.0)),
+                             test_ab<T>("a[] > 2 and a ilike '*Bc'"   ,"abc","",T(1.0)),
+                             test_ab<T>("a[] > 2 and a in '123abc123'","abc","",T(1.0)),
+
+                             test_ab<T>("a[] > 2 and a like b ","abc","*bc",T(1.0)),
+                             test_ab<T>("a[] > 2 and a ilike b","abc","*Bc",T(1.0)),
+                             test_ab<T>("a[] > 2 and a in b   ","abc","123abc123",T(1.0))
                            };
 
    static const std::size_t test_list_size = sizeof(test_list) / sizeof(test_ab<T>);
 
+   {
       const std::size_t rounds = 50;
+
       for (std::size_t r = 0; r < rounds; ++r)
       {
          bool result = true;
@@ -2294,13 +2331,13 @@ inline bool run_test02()
             T r3 = T(3);
 
             exprtk::symbol_table<T> symbol_table;
-         symbol_table.add_stringvar("a" ,str_a);
+            symbol_table.add_stringvar("a", str_a);
-         symbol_table.add_stringvar("b" ,str_b);
+            symbol_table.add_stringvar("b", str_b);
-         symbol_table.add_stringvar("c" ,str_c);
+            symbol_table.add_stringvar("c", str_c);
-         symbol_table.add_variable ("r0",   r0);
+            symbol_table.add_variable("r0", r0);
-         symbol_table.add_variable ("r1",   r1);
+            symbol_table.add_variable("r1", r1);
-         symbol_table.add_variable ("r2",   r2);
+            symbol_table.add_variable("r2", r2);
-         symbol_table.add_variable ("r3",   r3);
+            symbol_table.add_variable("r3", r3);
 
             exprtk::expression<T> expression;
             expression.register_symbol_table(symbol_table);
@@ -2308,7 +2345,7 @@ inline bool run_test02()
             {
                exprtk::parser<T> parser;
 
-            if (!parser.compile(test.expr,expression))
+               if (!parser.compile(test.expr, expression))
                {
                   printf("run_test02() - Error: %s   Expression: %s\n",
                      parser.error().c_str(),
@@ -2325,7 +2362,7 @@ inline bool run_test02()
 
             T expr_result = expression.value();
 
-         if (not_equal(expr_result,test.result))
+            if (not_equal(expr_result, test.result))
             {
                printf("run_test02() - Computation Error:  Expression: [%s]\tExpected: %19.15f\tResult: %19.15f\t"
                   "a='%s'\tb='%s'\tc='%s'\n",
@@ -2346,6 +2383,7 @@ inline bool run_test02()
             return false;
          }
       }
+   }
 
    {
       std::string s0;
@@ -2492,6 +2530,117 @@ inline bool run_test03()
       expression.value();
    }
 
+   {
+      static const std::string invalid_expr[] =
+                                 {
+                                   "x y",
+                                   "x y z",
+                                   "x y z w",
+                                   "x 1",
+                                   "x 1 2",
+                                   "x 1 2 3",
+                                   "x 'abc'",
+                                   "x 1 'abc'",
+                                   "x 'abc' 1",
+                                   "1 2",
+                                   "1 2 3",
+                                   "1 2 3 4",
+                                   "'abc' 'xyz'",
+                                   "'abc' 1",
+                                   "1 'abc'",
+                                   "x sin(1)",
+                                   "s 'abc'",
+                                   "s x",
+                                   "s y",
+                                   "s 1",
+                                   "s 1 x",
+                                   "s 1 y",
+                                   "s x 1",
+                                   "s y 1",
+                                   "x s ",
+                                   "y s ",
+                                   "1 s ",
+                                   "1 s x",
+                                   "1 s y",
+                                   "x s 1",
+                                   "y s 1",
+                                   "v 'abc'",
+                                   "v x  ",
+                                   "v y  ",
+                                   "v s  ",
+                                   "v 1  ",
+                                   "v 1 x",
+                                   "v 1 y",
+                                   "v 1 s",
+                                   "v x 1",
+                                   "v y 1",
+                                   "v s 1",
+                                   "x v  ",
+                                   "y v  ",
+                                   "1 v  ",
+                                   "1 v x",
+                                   "1 v y",
+                                   "x v 1",
+                                   "y v 1"
+                                 };
+
+      const std::size_t invalid_expr_size = sizeof(invalid_expr) / sizeof(std::string);
+
+      {
+         for (std::size_t i = 0; i < invalid_expr_size; ++i)
+         {
+            exprtk::symbol_table<T> symbol_table;
+
+            exprtk::expression<T> expression;
+
+            T x = T(0);
+            std::string s;
+            std::vector<T> v(10, T(1.234));
+
+            symbol_table.add_variable ("x",x);
+            symbol_table.add_stringvar("s",s);
+            symbol_table.add_vector   ("v",v);
+
+            exprtk::parser<T> parser;
+
+            if (parser.compile(invalid_expr[i],expression))
+            {
+               printf("run_test03() - Error: [1] Invalid expression compiled successfuly.   Expression: %s\n",
+                      invalid_expr[i].c_str());
+
+               return false;
+            }
+         }
+      }
+
+      {
+         T x = T(0);
+         std::string s;
+         std::vector<T> v(10, T(1.234));
+
+         exprtk::symbol_table<T> symbol_table;
+
+         symbol_table.add_variable ("x",x);
+         symbol_table.add_stringvar("s",s);
+         symbol_table.add_vector   ("v",v);
+
+         exprtk::parser<T> parser;
+
+         for (std::size_t i = 0; i < invalid_expr_size; ++i)
+         {
+            exprtk::expression<T> expression;
+
+            if (parser.compile(invalid_expr[i],expression))
+            {
+               printf("run_test03() - Error: [2] Invalid expression compiled successfuly.   Expression: %s\n",
+                      invalid_expr[i].c_str());
+
+               return false;
+            }
+         }
+      }
+   }
+
    return true;
 }
 
@@ -2977,9 +3126,16 @@ struct myfunc : public exprtk::ifunction<T>
    }
 };
 
+double foo1(double v0) { return v0; }
+double foo2(double v0, double v1) { return v0 + v1; }
+double foo3(double v0, double v1, double v2) { return v0 + v1 + v2; }
+double foo4(double v0, double v1, double v2, double v3) { return v0 + v1 + v2 + v3; }
+double foo5(double v0, double v1, double v2, double v3, double v4) { return v0 + v1 + v2 + v3 + v4; }
+
 template <typename T>
 inline bool run_test09()
 {
+   {
       static const std::size_t rounds = 1000;
       for (std::size_t i = 0; i < rounds; ++i)
       {
@@ -3067,6 +3223,53 @@ inline bool run_test09()
             return false;
          }
       }
+   }
+
+   {
+      typedef exprtk::expression<T>   expression_t;
+      typedef exprtk::symbol_table<T> symbol_table_t;
+
+      bool result = true;
+
+      const std::string expression_list[] =
+                           {
+                             "foo1(1)         == 1",
+                             "foo2(1,2)       == (1 + 2)",
+                             "foo3(1,2,3)     == (1 + 2 + 3)",
+                             "foo4(1,2,3,4)   == (1 + 2 + 3 + 4)",
+                             "foo5(1,2,3,4,5) == (1 + 2 + 3 + 4 + 5)"
+                           };
+
+      const std::size_t expression_list_size = sizeof(expression_list) / sizeof(std::string);
+
+      symbol_table_t symbol_table;
+
+      symbol_table.add_function("foo1",foo1);
+      symbol_table.add_function("foo2",foo2);
+      symbol_table.add_function("foo3",foo3);
+      symbol_table.add_function("foo4",foo4);
+      symbol_table.add_function("foo5",foo5);
+
+      for (std::size_t i = 0; i < expression_list_size; ++i)
+      {
+         expression_t expression;
+         expression.register_symbol_table(symbol_table);
+
+         exprtk::parser<T> parser;
+
+         if (!parser.compile(expression_list[i],expression))
+         {
+            printf("run_test09() - Error: %s   Expression: %s\n",
+                   parser.error().c_str(),
+                   expression_list[i].c_str());
+
+            result = false;
+         }
+      }
+
+      if (!result)
+         return false;
+   }
 
    return true;
 }
@@ -3081,12 +3284,10 @@ inline bool run_test10()
    T xx = T(3.3);
    T yy = T(4.4);
 
-   std::string i  = "A String";
+   std::string i_s  = "A String";
-   std::string j  = "Another String";
+   std::string j_s  = "Another String";
-   std::string ii = "A String";
+   std::string ii_s = "A String";
-   std::string jj = "Another String";
+   std::string jj_s = "Another String";
-
-   exprtk::symbol_table<T> symbol_table;
 
    struct test
    {
@@ -3111,14 +3312,17 @@ inline bool run_test10()
       }
    };
 
+   {
       static const std::size_t rounds = 10;
 
+      exprtk::symbol_table<T> symbol_table;
+
       for (std::size_t r = 0; r < rounds; ++r)
       {
          symbol_table.add_variable("x", x);
          symbol_table.add_variable("y", y);
-      symbol_table.add_variable("xx",xx);
+         symbol_table.add_variable("xx", xx);
-      symbol_table.add_variable("yy",yy);
+         symbol_table.add_variable("yy", yy);
 
          if (!symbol_table.symbol_exists("x"))
          {
@@ -3140,22 +3344,22 @@ inline bool run_test10()
             printf("run_test10() - Symbol 'yy' does not exist!\n");
             return false;
          }
-      else if (!test::variable(symbol_table,"x",x))
+         else if (!test::variable(symbol_table, "x", x))
          {
             printf("run_test10() - Symbol 'x' value failure!\n");
             return false;
          }
-      else if (!test::variable(symbol_table,"y",y))
+         else if (!test::variable(symbol_table, "y", y))
          {
             printf("run_test10() - Symbol 'y' value failure!\n");
             return false;
          }
-      else if (!test::variable(symbol_table,"xx",xx))
+         else if (!test::variable(symbol_table, "xx", xx))
          {
             printf("run_test10() - Symbol 'xx' value failure!\n");
             return false;
          }
-      else if (!test::variable(symbol_table,"yy",yy))
+         else if (!test::variable(symbol_table, "yy", yy))
          {
             printf("run_test10() - Symbol 'yy' value failure!\n");
             return false;
@@ -3187,8 +3391,8 @@ inline bool run_test10()
       {
          myfunc<T> mf;
 
-      symbol_table.add_function("f",mf);
+         symbol_table.add_function("f", mf);
-      symbol_table.add_function("f1",mf);
+         symbol_table.add_function("f1", mf);
 
          if (!symbol_table.symbol_exists("f"))
          {
@@ -3215,11 +3419,11 @@ inline bool run_test10()
 
       for (std::size_t r = 0; r < rounds; ++r)
       {
-      symbol_table.add_stringvar("i",i);
+         symbol_table.add_stringvar("i", i_s);
-      symbol_table.add_stringvar("j",j);
+         symbol_table.add_stringvar("j", j_s);
 
-      symbol_table.add_stringvar("ii",ii);
+         symbol_table.add_stringvar("ii", ii_s);
-      symbol_table.add_stringvar("jj",jj);
+         symbol_table.add_stringvar("jj", jj_s);
 
          if (!symbol_table.symbol_exists("i"))
          {
@@ -3241,22 +3445,22 @@ inline bool run_test10()
             printf("run_test10() - String 'jj' does not exist!\n");
             return false;
          }
-      else if (!test::string(symbol_table,"i",i))
+         else if (!test::string(symbol_table, "i", i_s))
          {
             printf("run_test10() - String 'i' value failure!\n");
             return false;
          }
-      else if (!test::string(symbol_table,"j",j))
+         else if (!test::string(symbol_table, "j", j_s))
          {
             printf("run_test10() - String 'j' value failure!\n");
             return false;
          }
-      else if (!test::string(symbol_table,"ii",ii))
+         else if (!test::string(symbol_table, "ii", ii_s))
          {
             printf("run_test10() - String 'ii' value failure!\n");
             return false;
          }
-      else if (!test::string(symbol_table,"jj",jj))
+         else if (!test::string(symbol_table, "jj", jj_s))
          {
             printf("run_test10() - String 'jj' value failure!\n");
             return false;
@@ -3287,17 +3491,17 @@ inline bool run_test10()
       {
          symbol_table.add_variable("x", x);
          symbol_table.add_variable("y", y);
-      symbol_table.add_variable("xx",xx);
+         symbol_table.add_variable("xx", xx);
-      symbol_table.add_variable("yy",yy);
+         symbol_table.add_variable("yy", yy);
 
          std::vector<std::string> expected_var_list;
 
-      expected_var_list.push_back( "x");
+         expected_var_list.push_back("x");
-      expected_var_list.push_back( "y");
+         expected_var_list.push_back("y");
          expected_var_list.push_back("xx");
          expected_var_list.push_back("yy");
 
-      std::deque<std::pair<std::string,T> > variable_list;
+         std::deque<std::pair<std::string, T> > variable_list;
 
          symbol_table.get_variable_list(variable_list);
 
@@ -3332,13 +3536,13 @@ inline bool run_test10()
       {
          symbol_table.add_variable("x", x);
          symbol_table.add_variable("y", y);
-      symbol_table.add_variable("xx",xx);
+         symbol_table.add_variable("xx", xx);
-      symbol_table.add_variable("yy",yy);
+         symbol_table.add_variable("yy", yy);
 
          std::vector<std::string> expected_var_list;
 
-      expected_var_list.push_back( "x");
+         expected_var_list.push_back("x");
-      expected_var_list.push_back( "y");
+         expected_var_list.push_back("y");
          expected_var_list.push_back("xx");
          expected_var_list.push_back("yy");
 
@@ -3375,19 +3579,19 @@ inline bool run_test10()
 
       for (std::size_t r = 0; r < rounds; ++r)
       {
-      symbol_table.add_stringvar( "i", i);
+         symbol_table.add_stringvar("i", i_s);
-      symbol_table.add_stringvar( "j", j);
+         symbol_table.add_stringvar("j", j_s);
-      symbol_table.add_stringvar("ii",ii);
+         symbol_table.add_stringvar("ii", ii_s);
-      symbol_table.add_stringvar("jj",jj);
+         symbol_table.add_stringvar("jj", jj_s);
 
          std::vector<std::string> expected_var_list;
 
-      expected_var_list.push_back( "i");
+         expected_var_list.push_back("i");
-      expected_var_list.push_back( "j");
+         expected_var_list.push_back("j");
          expected_var_list.push_back("ii");
          expected_var_list.push_back("jj");
 
-      std::deque<std::pair<std::string,std::string> > stringvar_list;
+         std::deque<std::pair<std::string, std::string> > stringvar_list;
 
          symbol_table.get_stringvar_list(stringvar_list);
 
@@ -3420,15 +3624,15 @@ inline bool run_test10()
 
       for (std::size_t r = 0; r < rounds; ++r)
       {
-      symbol_table.add_stringvar( "i", i);
+         symbol_table.add_stringvar("i", i_s);
-      symbol_table.add_stringvar( "j", j);
+         symbol_table.add_stringvar("j", j_s);
-      symbol_table.add_stringvar("ii",ii);
+         symbol_table.add_stringvar("ii", ii_s);
-      symbol_table.add_stringvar("jj",jj);
+         symbol_table.add_stringvar("jj", jj_s);
 
          std::vector<std::string> expected_var_list;
 
-      expected_var_list.push_back( "i");
+         expected_var_list.push_back("i");
-      expected_var_list.push_back( "j");
+         expected_var_list.push_back("j");
          expected_var_list.push_back("ii");
          expected_var_list.push_back("jj");
 
@@ -3468,6 +3672,7 @@ inline bool run_test10()
             return false;
          }
       }
+   }
 
    {
       T x0 = T(0);
@@ -3977,6 +4182,9 @@ inline bool run_test10()
         "2 == for (var i := 0; i < 10; i += 1) { if (i > 2) { continue; return [i * 8];"
         "i += 1; i += 2; i += 3; } else i; }",
 
+        "var x[10] := [-1]; var y[10] := [-1]; for (var i := 0; i < 10; i += 1) { x[i] := i; "
+        "y[i] := 2 * x[i]; }; (sum(x) == 45) and (sum(y) == (2 * sum(x)));"
+
         "7 == (for (var i := 0; i < 10; i += 1) { ~{break[7]; continue; i += i} })",
         "0 == (for (var i := 0; i < 10; i += 1) { ~{break[i]; continue; i += i} })",
         "0 == (for (var i := 0; i < 10; i += 1) { ~{continue; break[7]; i += i} })",
@@ -4932,6 +5140,8 @@ struct va_func : public exprtk::ivararg_function<T>
    va_func()
    {
       exprtk::enable_zero_parameters(*this);
+      exprtk::set_min_num_args(*this,  0);
+      exprtk::set_max_num_args(*this, 20);
    }
 
    inline T operator()(const std::vector<T>& arglist)
@@ -5084,12 +5294,13 @@ struct inc_func : public exprtk::igeneric_function<T>
 template <typename T>
 struct rem_space_and_uppercase : public exprtk::igeneric_function<T>
 {
-   typedef typename exprtk::igeneric_function<T>::generic_type generic_type;
+   typedef typename exprtk::igeneric_function<T> igenfunc_t;
-   typedef typename exprtk::igeneric_function<T>::parameter_list_t parameter_list_t;
+   typedef typename igenfunc_t::generic_type     generic_type;
+   typedef typename igenfunc_t::parameter_list_t parameter_list_t;
    typedef typename generic_type::string_view    string_t;
 
    rem_space_and_uppercase()
-   : exprtk::igeneric_function<T>("S")
+   : igenfunc_t("S",igenfunc_t::e_rtrn_string)
    {}
 
    inline T operator()(std::string& result, parameter_list_t params)
@@ -5104,7 +5315,7 @@ struct rem_space_and_uppercase : public exprtk::igeneric_function<T>
       for (std::size_t i = 0; i < string.size(); ++i)
       {
          if (' ' != (c = string[i]))
-            result += std::toupper(c);
+            result += static_cast<char>(std::toupper(c));
       }
 
       return T(0);
@@ -5613,7 +5824,7 @@ inline bool run_test18()
       symbol_table.add_stringvar("s3", s3);
       symbol_table.add_stringvar("s4", s4);
 
-      symbol_table.add_function("remspc_uc",rsauc,symbol_table_t::e_ft_strfunc);
+      symbol_table.add_function("remspc_uc",rsauc);
 
       std::string program = " s0 := 'How now ';                                   "
                             " s1 := 'brown cow?';                                 "

readme.txt

@@ -610,9 +610,9 @@ appropriate may represent any of one the following:
 ExprTk supports three fundamental types which can be used freely in
 expressions. The types are as follows:
 
-   1. Scalar
+   (1) Scalar
-   2. Vector
+   (2) Vector
-   3. String
+   (3) String
 
 
 (1) Scalar Type
@@ -706,7 +706,7 @@ current values assigned to the variables will be used.
    expression.value(); // 3.7 * -9 + 3
 
    // 'x * -9 + 3' for x in range of [0,100) in steps of 0.0001
-   for (x = 0; x < 100; x += 0.0001)
+   for (x = 0.0; x < 100.0; x += 0.0001)
    {
       expression.value(); // x * -9 + 3
    }
@@ -860,7 +860,10 @@ handle:
    (i) '*' '='  --->  '*='  (multiplication assignment)
    (j) '/' '='  --->  '/='  (division assignment)
    (k) '%' '='  --->  '%='  (modulo assignment)
-   (l) '<=' '>' --->  '<=>' (swap)
+   (l) '+' '-'  --->  '-'   (subtraction)
+   (m) '-' '+'  --->  '-'   (subtraction)
+   (n) '-' '-'  --->  '+'   (addition)
+   (o) '<=' '>' --->  '<=>' (swap)
 
 
 An example of the transformation that takes place is as follows:
@@ -926,7 +929,7 @@ In  the following  example the  given expression  which represents  an
 attempt at computing the average  between x and y will  be transformed
 as follows:
 
-   (x * 0.5) + (y * 0.5) ---> 0.5 * (x + y)
+   (0.5 * x) + (y * 0.5) ---> 0.5 * (x + y)
 
 There  may be  situations where  the above  transformation will  cause
 numerical overflows and  that the original  form of the  expression is
@@ -1216,11 +1219,15 @@ embedded into the expression.
 
 There are five types of function interface:
 
-   (1) ifunction
+   +---+----------------------+-------------+
-   (2) ivararg_function
+   | # |         Name         | Return Type |
-   (3) igeneric_function
+   +---+----------------------+-------------+
-   (4) igeneric_function II
+   | 1 | ifunction            | Scalar      |
-   (5) function_compositor
+   | 2 | ivararg_function     | Scalar      |
+   | 3 | igeneric_function    | Scalar      |
+   | 4 | igeneric_function II | String      |
+   | 5 | function_compositor  | Scalar      |
+   +---+----------------------+-------------+
 
 
 (1) ifunction
@@ -1446,17 +1453,21 @@ the string return type function operator being explicitly overridden:
       typedef typename generic_t::string_view string_t;
 
       toupper()
-      : exprtk::igeneric_function<T>("S")
+      : exprtk::igeneric_function<T>("S",igenfunct_t::e_rtrn_string)
       {}
 
       inline T operator()(std::string& result,
                           parameter_list_t parameters)
       {
          result.clear();
+
+         string_t string(params[0]);
+
          for (std::size_t i = 0; i < string.size(); ++i)
          {
             result += std::toupper(string[i]);
          }
+
          return T(0);
       }
    };
@@ -1464,27 +1475,27 @@ the string return type function operator being explicitly overridden:
 
 In the example above the  generic function 'toupper' expects only  one
 input parameter  of type  string, as  noted by  the parameter sequence
-string passed during the constructor. When executed, the function will
+string passed during the  constructor. Furthermore a second  parameter
-return as a result a copy  of the input string converted to  uppercase
+is passed to the constructor indicating that it should be treated as a
-form. An example expression  using the toupper function  registered as
+string returning function -  by default it is  assumed to be a  scalar
-the symbol 'toupper' is as follows:
+returning function.
+
+When executed,  the function  will return  as a  result a  copy of the
+input string converted to uppercase form. An example expression  using
+the toupper function registered as the symbol 'toupper' is as follows:
 
    "'ABCDEF' == toupper('aBc') + toupper('DeF')"
 
 
 Note: When adding a string type returning generic function to a symbol
-table,  the  'add_function'  is   invoked  with  an  extra   parameter
+table the  'add_function' is invoked.  The example  below demonstrates
-(e_ft_strfunc) that denotes the function should be treated as a string
+how this can be done:
-returning function type. The  following example demonstrates how  this
-is done:
 
    toupper<T> tu;
 
    exprtk::symbol_table<T> symbol_table;
 
-   symbol_table.add_function("toupper",
+   symbol_table.add_function("toupper",tu);
-                             tu,
-                             symbol_table_t::e_ft_strfunc);
 
 
 Note: Two further  refinements to the  type checking facility  are the
@@ -1689,7 +1700,7 @@ the function can be disabled.
    {
       foo() : exprtk::ifunction<T>(3)
       {
-         disable_has_side_effects(*this);
+          exprtk::disable_has_side_effects(*this);
       }
 
       T operator()(const T& v1, const T& v2, const T& v3)
@@ -1757,6 +1768,14 @@ parsing  phase.   Once  the   compilation  process   has  successfully
 completed, the  caller can  then obtain  a list  of symbols  and their
 associated types from the DEC.
 
+The kinds of  questions one can  ask regarding the  dependent entities
+within an expression are as follows:
+
+  * What user defined or local variables, vectors or strings are used?
+  * What functions or custom user functions are used?
+  * Which variables, vectors or strings have values assigned to them?
+
+
 The following example demonstrates usage of the DEC in determining the
 dependents of the given expression:
 
@@ -1766,9 +1785,15 @@ dependents of the given expression:
    std::string expression_string =
                   "z := abs(x + sin(2 * pi / y))";
 
+   T x,y,z;
+
    parser_t parser;
    symbol_table_t symbol_table;
 
+   symbol_table.add_variable("x",x);
+   symbol_table.add_variable("y",y);
+   symbol_table.add_variable("z",z);
+
    expression_t expression;
    expression.register_symbol_table(symbol_table);
 
@@ -1799,7 +1824,7 @@ dependents of the given expression:
    }
 
 
-Note: The  'symbol_t' type  is a  pair comprising  of the  symbol name
+Note: The 'symbol_t' type is a std::pair comprising of the symbol name
 (std::string) and the associated type of the symbol as denoted by  the
 cases in the switch statement.
 
@@ -1866,6 +1891,9 @@ grammar. The features fall into one of the following three categories:
    (1) Base Functions
    (2) Control Flow Structures
    (3) Logical Operators
+   (4) Arithmetic Operators
+   (5) Inequality Operators
+   (6) Assignment Operators
 
 
 (1) Base Functions
@@ -1967,13 +1995,13 @@ flow structure:
        " }                                ";
 
     parser.settings()
-      .disable_all_control_structures(settings_t::e_ctrl_for_loop);
+      .disable_control_structure(settings_t::e_ctrl_for_loop);
 
     parser
       .compile(program,expression); // failure
 
     parser.settings()
-      .enable_all_control_structures(settings_t::e_ctrl_for_loop);
+      .enable_control_structure(settings_t::e_ctrl_for_loop);
 
     parser
       .compile(program,expression); // success
@@ -2009,18 +2037,158 @@ example  demonstrates  the disabling  of  the 'and' logical operator:
     expression_t expression;
 
     parser.settings()
-      .disable_base_function(settings_t::e_logic_and);
+      .disable_logic_operation(settings_t::e_logic_and);
 
     parser
       .compile("1 or not(0 and 1)",expression); // failure
 
     parser.settings()
-      .enable_base_function(settings_t::e_logic_and);
+      .enable_logic_operation(settings_t::e_logic_and);
 
     parser
       .compile("1 or not(0 and 1)",expression); // success
 
 
+(4) Arithmetic Operators
+The list of available arithmetic operators is as follows:
+
+   +, -, *, /, %, ^
+
+
+The  above  mentioned  arithmetic  operators  can  be  either  enabled or
+disabled 'all' at once, as is demonstrated below:
+
+    parser_t parser;
+    expression_t expression;
+
+    parser.settings().disable_all_arithmetic_ops();
+
+    parser
+      .compile("1 + 2 / 3",expression); // compilation failure
+
+    parser.settings().enable_all_arithmetic_ops();
+
+    parser
+      .compile("1 + 2 / 3",expression); // compilation success
+
+
+One can also enable or disable specific arithmetic operators. The  following
+example demonstrates the disabling of  the addition '+' arithmetic operator:
+
+    parser_t parser;
+    expression_t expression;
+
+    parser.settings()
+      .disable_arithmetic_operation(settings_t::e_arith_add);
+
+    parser
+      .compile("1 + 2 / 3",expression); // failure
+
+    parser.settings()
+      .enable_arithmetic_operation(settings_t::e_arith_add);
+
+    parser
+      .compile("1 + 2 / 3",expression); // success
+
+
+(5) Inequality Operators
+The list of available inequality operators is as follows:
+
+   <, <=, >, >=, ==, =, != <>
+
+
+The  above  mentioned  inequality  operators  can  be  either  enabled or
+disabled 'all' at once, as is demonstrated below:
+
+    parser_t parser;
+    expression_t expression;
+
+    parser.settings().disable_all_inequality_ops();
+
+    parser
+      .compile("1 < 3",expression); // compilation failure
+
+    parser.settings().enable_all_inequality_ops();
+
+    parser
+      .compile("1 < 3",expression); // compilation success
+
+
+One can also enable or disable specific inequality operators. The  following
+example demonstrates the disabling of the less-than '<' inequality operator:
+
+    parser_t parser;
+    expression_t expression;
+
+    parser.settings()
+      .disable_inequality_operation(settings_t::e_ineq_lt);
+
+    parser
+      .compile("1 < 3",expression); // failure
+
+    parser.settings()
+      .enable_inequality_operation(settings_t::e_ineq_lt);
+
+    parser
+      .compile("1 < 3",expression); // success
+
+
+(6) Assignment Operators
+The list of available assignment operators is as follows:
+
+   :=, +=, -=, *=, /=, %=
+
+
+The  above  mentioned  assignment  operators  can  be  either  enabled or
+disabled 'all' at once, as is demonstrated below:
+
+    parser_t parser;
+    expression_t expression;
+    symbol_table_t symbol_table;
+
+    T x = T(0);
+
+    symbol_table.add_variable("x",x);
+
+    expression.register_symbol_table(symbol_table);
+
+    parser.settings().disable_all_assignment_ops();
+
+    parser
+      .compile("x := 3",expression); // compilation failure
+
+    parser.settings().enable_all_assignment_ops();
+
+    parser
+      .compile("x := 3",expression); // compilation success
+
+
+One can also enable or disable specific assignment operators. The  following
+example demonstrates the disabling of the '+=' addition assignment operator:
+
+    parser_t parser;
+    expression_t expression;
+    symbol_table_t symbol_table;
+
+    T x = T(0);
+
+    symbol_table.add_variable("x",x);
+
+    expression.register_symbol_table(symbol_table);
+
+    parser.settings()
+      .disable_assignment_operation(settings_t::e_assign_addass);
+
+    parser
+      .compile("x += 3",expression); // failure
+
+    parser.settings()
+      .enable_assignment_operation(settings_t::e_assign_addass);
+
+    parser
+      .compile("x += 3",expression); // success
+
+
 Note: In the event of a base function being disabled, one can redefine
 the  base  function  using  the  standard  custom  function definition
 process. In the  following example the 'sin' function is disabled then
@@ -2161,7 +2329,7 @@ following example:
    if (!parser.compile(expression_string,expression))
    {
       printf("Error: %s\n", parser.error().c_str());
-      return 1;
+      return false;
    }
 
 
@@ -2189,7 +2357,7 @@ in the event of a failed compilation.
                 error.diagnostic.c_str());
       }
 
-      return 1;
+      return false;
    }
 
 
@@ -2214,7 +2382,7 @@ demonstrated by the following example:
                 error.column_no);
       }
 
-      return 1;
+      return false;
    }
 
 
@@ -2530,7 +2698,15 @@ int main()
 When building ExprTk there are a number of defines that will enable or
 disable certain features and  capabilities. The defines can  either be
 part of a compiler command line switch or scoped around the include to
-the ExprTk header.
+the ExprTk header. The defines are as follows:
+
+   (1) exprtk_enable_debugging
+   (2) exprtk_disable_comments
+   (3) exprtk_disable_break_continue
+   (4) exprtk_disable_sc_andor
+   (5) exprtk_disable_enhanced_features
+   (6) exprtk_disable_string_capabilities
+
 
 (1) exprtk_enable_debugging
 This define will enable printing of debug information to stdout during