public IToken Apply(IToken arg)
{
return(KComb.Acquire());
}
public IToken ParseTokens(string[] ops)
{
var stack = new Stack <ApOperator>();
IToken token = null;
for (int i = 0; i < ops.Length; i++)
{
var op = ops[i];
switch (op)
{
case "ap":
token = new ApOperator();
break;
case "inc":
token = IncOperator.Acquire();
break;
case "dec":
token = DecOperator.Acquire();
break;
case "neg":
token = NegOperator.Acquire();
break;
case "add":
token = AddOperator.Acquire();
break;
case "mul":
token = MulOperator.Acquire();
break;
//case "l":
// token = new LOperator();
// break;
case "div":
token = DivOperator.Acquire();
break;
//case "pwr2":
// return (new Pwr2Operator(), index);
case "t":
token = KComb.Acquire();
break;
//case "f":
// return (new FComb(), index);
case "s":
token = SComb.Acquire();
break;
case "c":
token = CComb.Acquire();
break;
case "b":
token = BComb.Acquire();
break;
case "i":
token = IComb.Acquire();
break;
case "cons":
case "vec":
token = ConsOperator.Acquire();
break;
case "car":
token = CarOperator.Acquire();
break;
case "cdr":
token = CdrOperator.Acquire();
break;
case "nil":
token = NilOperator.Acquire();
break;
case "isnil":
token = IsNilOperator.Acquire();
break;
case "eq":
token = EqOperator.Acquire();
break;
case "if0":
token = new If0Operator();
break;
case "lt":
token = LtOperator.Acquire();
break;
//case "mod":
// token = new ModOperator();
// break;
//case "dem":
// token = new DemodOperator();
// break;
case "interact":
token = new InteractOperator();
break;
default:
if (decimal.TryParse(op, out var constant)) // int constant
{
token = ConstantOperator.Acquire(decimal.Parse(op));
}
else if (op.StartsWith("x"))
{
token = VarOperator.Acquire(op);
}
else if (op.StartsWith(":")) // variable reference
{
token = LateBoundToken.Acquire(op);
}
else
{
throw new InvalidOperationException();
}
break;
}
if (stack.Count == 0)
{
if (!(token is ApOperator))
{
if (i != ops.Length - 1)
{
throw new InvalidOperationException();
}
return(token);
}
stack.Push((ApOperator)token);
}
else
{
var top = stack.Peek();
if (top.f == null)
{
top.f = token;
if (token is ApOperator ap)
{
stack.Push(ap);
}
}
else if (top.x == null)
{
top.x = token;
if (token is ApOperator ap)
{
stack.Push(ap);
}
else
{
while (stack.Count > 0 && stack.Peek().x != null)
{
token = stack.Pop();
}
}
}
else
{
throw new InvalidOperationException();
}
}
}
if (stack.Count == 1)
{
return(stack.Pop());
}
return(token);
}