private static string OnTraversePrefixExpression(this IPrefixExpression prefix, Func <string, Operators, string, string> action)
{
Stack <string> stack = new Stack <string>();
IParsedExpression parsed = prefix.ParseExpression();
// Length of expression
int l = parsed.Value.Length;
// Reading from right to left
for (int i = l - 1; i >= 0; i--)
{
char c = parsed.Value[i];
// Check whether the character is an operator
if (c.IsOperator())
{
// Check whether the character is operator of type Negation
if (((char)Operators.Negation).Equals(c))
{
// Get the previous result from the stack,calculate the next nandified result and put it in the stack
string value = stack.Pop();
stack.Push(action(value, Operators.Negation, null));
}
else
{
// Get the previous result from the stack,calculate the next nandified result and put it in the stack
string value1 = stack.Pop();
string value2 = stack.Pop();
stack.Push(action(value1, (Operators)c, value2));
}
}
else
{
// Put the variable in the stack
stack.Push($@"{c}");
}
}
return(stack.Pop());
}
public ExpressionStructure(IPrefixExpression expression)
{
this.PrefixExpression = expression ?? throw new NullReferenceException("Invalid prefix expression");
}