public MainWindow()
{
InitializeComponent();
grammar = new MathGrammar();
language = new LanguageData(grammar);
parser = new Parser(language);
}
//Default constructor, creates default evaluator
public ExpressionEvaluator(MathGrammar grammar)
{
Grammar = grammar;
Language = new LanguageData(Grammar);
Parser = new Parser(Language);
Runtime = Grammar.CreateRuntime(Language);
App = new ScriptApp(Runtime);
Globals.Add("null", Runtime.NoneValue);
Globals.Add("true", true);
Globals.Add("false", false);
}