added 'Delete' function to release the exprtk allocated memory

Author: Pramod-Devireddy

README.md

@@ -44,6 +44,7 @@ import (
 
 func main() {
 	exprtkObj := exprtk.NewExprtk()
+	defer exprtkObj.Delete()
 
 	exprtkObj.SetExpression("(x + 2)*(y-2)")
 

examples/example-01.go

@@ -9,6 +9,7 @@ import (
 func example01() {
 	// Create a new exprtk instance
 	exprtkObj := exprtk.NewExprtk()
+	defer exprtkObj.Delete()
 
 	// Set the expression
 	exprtkObj.SetExpression("(x + 2)*(y-2)")

examples/example-02.go

@@ -19,6 +19,8 @@ func example02() {
 	var array []float64 = []float64{1, 2, 3, -4.3, 10, -6.5, 7, 8, -1.3}
 
 	exprtkObj := exprtk.NewExprtk()
+	defer exprtkObj.Delete()
+
 	exprtkObj.SetExpression(eqn)
 	exprtkObj.AddStringVariable("eqn")
 	exprtkObj.AddVectorVariable("x")

exprtk.go

@@ -74,3 +74,8 @@ func (obj GoExprtk) CompileExpression() error {
 func (obj GoExprtk) GetEvaluatedValue() float64 {
 	return float64(C.getEvaluatedValue(obj.exprtk))
 }
+
+// Delete ... Destroys the created object and releases the memory
+func (obj GoExprtk) Delete() {
+	C.deleteExprtk(obj.exprtk)
+}

exprtk_test.go

@@ -9,6 +9,7 @@ import (
 
 func TestNewExprtk(t *testing.T) {
 	exprtkObj := NewExprtk()
+	defer exprtkObj.Delete()
 
 	if reflect.TypeOf(exprtkObj).String() != "exprtk.GoExprtk" {
 		t.Error("NewExprtk returned incorrect type")
@@ -17,6 +18,7 @@ func TestNewExprtk(t *testing.T) {
 
 func TestCompileExpression(t *testing.T) {
 	exprtkObj := NewExprtk()
+	defer exprtkObj.Delete()
 
 	exprtkObj.SetExpression("x.1 + y.1")
 
@@ -41,6 +43,7 @@ func TestCompileExpression(t *testing.T) {
 
 func TestDoubleVariables(t *testing.T) {
 	exprtkObj := NewExprtk()
+	defer exprtkObj.Delete()
 
 	exprtkObj.SetExpression("(x + 2)*(y-2)")
 
@@ -74,6 +77,8 @@ func TestMixedVariables(t *testing.T) {
 	var array []float64 = []float64{1, 2, 3, -4.3, 10, -6.5, 7, 8, -1.3}
 
 	exprtkObj := NewExprtk()
+	defer exprtkObj.Delete()
+
 	exprtkObj.SetExpression(eqn)
 	exprtkObj.AddStringVariable("eqn")
 	exprtkObj.AddVectorVariable("x")

exprtkwrapper.cpp

@@ -139,4 +139,9 @@ void addVectorVariable(exprtkWrapper obj, char* var)
     v->value.push_back(double(0));
     exprtkStruct->vectorValue.push_back(v);
     exprtkStruct->symbolTable.add_vector(v->varName,v->value);
+}
+
+void deleteExprtk(exprtkWrapper obj)
+{
+    delete (ExprtkStruct*)obj;
 }

exprtkwrapper.h

@@ -29,6 +29,8 @@ void setVectorVariableValue(exprtkWrapper, char* var, double val[], int len);
 
 double getEvaluatedValue(exprtkWrapper);
 
+void deleteExprtk(exprtkWrapper);
+
 
 #ifdef __cplusplus
 }