Allow as and is to use instances of System.Type

[zspitz]

The following:

class Foo { }
class Bar : Foo { }

var prm = Parameter(typeof(Foo));
var selector = $"as(@0)";
var parser = new ExpressionParser(new[] { prm }, selector, new object[] { typeof(Bar) }, ParsingConfig.Default);
var expr = parser.Parse(null);

fails with:

System.Linq.Dynamic.Core.Exceptions.ParseException: 'The 'as' function requires one argument which is not null.'

The same happens with is:

var selector = $"is(@0)";

It might be helpful to clarify the error by explaining that the one argument must be the FullName of the type.

But I suggest it be possible to accept a System.Type, and FullName should be read from the type.

[StefH]

I've updated the code to support also Type for As, Is, OfType and Cast.

However, it needs to be a constant value (note that your example works fine with the code fix)

[zspitz]

However, it needs to be a constant value

In other words, if I have a property or method which returns a Type, it's not going to work?

[StefH]

Correct, that will not yet work.