private Expr Diff(Expr expr)
{
if (expr.A == Action.A)
{
if (expr.LS == null && expr.RS == null)
{
Expr left = Diff(expr.LE);
Expr right = Diff(expr.RE);
return new Expr(Action.A, null, left, null, right);
}
else if (expr.LS == null)
{
Expr left = Diff(expr.LE);
string right = (isX(expr.RS)) ? "1" : "0";
return new Expr(Action.A, null, left, right, null);
}
else if (expr.RS == null)
{
Expr right = Diff(expr.RE);
string left = (isX(expr.LS)) ? "1" : "0";
return new Expr(Action.A, left, null, null, right);
}
else
{
string left = (isX(expr.LS)) ? "1" : "0";
string right = (isX(expr.RS)) ? "1" : "0";
return new Expr(Action.A, left, null, right, null);
}
}
else
{
if (expr.LS == null && expr.RS == null)
{
Expr left = new Expr(Action.M, null, Diff(expr.LE), null, expr.RE);
Expr right = new Expr(Action.M, null, expr.LE, null, Diff(expr.RE));
return new Expr(Action.A, null, left, null, right);
}
else if (expr.LS == null)
{
Expr left = new Expr(Action.M, null, Diff(expr.LE), expr.RS, null);
Expr right = new Expr(Action.M, null, expr.LE, (isX(expr.RS)) ? "1" : "0", null);
return new Expr(Action.A, null, left, null, right);
}
else if (expr.RS == null)
{
Expr left = new Expr(Action.M, (isX(expr.LS)) ? "1" : "0", null, null, expr.RE);
Expr right = new Expr(Action.M, expr.LS, null, null, Diff(expr.RE));
return new Expr(Action.A, null, left, null, right);
}
else
return new Expr(Action.M, "0", null, "0", null);
}
}
static void Main(string[] args)
{
Expr expr = new Expr(Expr.Action.M, "X", null, null, new Expr(Expr.Action.A, "X", null, "1", null));
Expr diff = expr.Diff();
Console.WriteLine("Expr: " + expr.ToString());
Console.WriteLine("Diff: " + diff.ToString());
Mult exp = new Mult(new X(), new Add(new X(), new Num(1)));
Console.WriteLine(exp.Print());
Console.WriteLine(exp.Diff().Print());
}
public Expr(Action a, string sl, Expr el, string sr, Expr er)
{
A = a;
LS = sl;
RS = sr;
LE = el;
RE = er;
}