protected override SyntaxToken VisitFunction(FunctionSyntaxToken token)
{
SyntaxToken arg = token.Arguments[0];
SyntaxToken diff = this.Visit(arg);
SyntaxToken one = SyntaxToken.Constant(1);
SyntaxToken two = SyntaxToken.Constant(2);
SyntaxToken result;
switch (token.Type)
{
case FunctionType.Sin:
result = SyntaxToken.Cos(arg);
break;
case FunctionType.Cos:
result = SyntaxToken.Negate(SyntaxToken.Sin(arg));
break;
case FunctionType.Tan:
result = SyntaxToken.Add(one, SyntaxToken.Pow(SyntaxToken.Tan(arg), two));
break;
case FunctionType.Cot:
result = SyntaxToken.Negate(SyntaxToken.Add(one, SyntaxToken.Pow(SyntaxToken.Cot(arg), two)));
break;
case FunctionType.Asin:
result = SyntaxToken.Divide(one, SyntaxToken.Root(SyntaxToken.Subtract(one, SyntaxToken.Pow(arg, two)), two));
break;
case FunctionType.Acos:
result = -(one / SyntaxToken.Root(one - SyntaxToken.Pow(arg, two), two));
break;
case FunctionType.Atan:
result = one / (one + SyntaxToken.Pow(arg, two));
break;
case FunctionType.Acot:
result = -(one / (one + SyntaxToken.Pow(arg, two)));
break;
case FunctionType.Log:
SyntaxToken b = token.Arguments[1];
result = one / (arg * SyntaxToken.Ln(b));
break;
case FunctionType.Ln:
result = one / arg;
break;
case FunctionType.Abs:
result = arg / SyntaxToken.Abs(arg);
break;
case FunctionType.Unsupported:
default: throw new NotSupportedException();
}
return(result * diff);
}