public void Test()
{
string str = "10 + 2 - 5 + 4 + 9";
Context context = new Context(str);
AbstractExpression expression = new NonterminalExpression();
int result = expression.Interpret(context);
Assert.AreEqual(30, result);
}
static void Main(string[] args)
{
Context context = new Context
{
Vocabulary = 'a',
Source = "aaa"
};
var expression = new NonterminalExpression();
expression.Interpret(context);
Console.WriteLine(context.Result);
}