Support for comparing two properties

[paw3lx]

I think it could be nice to have ability to compare two properties of an object:

.Ensure(m => m.Password, _ => _.IsEqualTo(m => m.RePassword))

What do you think about it?

[GooRiOn]

Yup, that looks cool. Do you want to create an overload for each binary operation, or just IsEqualTo() ?

[paw3lx]

It will be great to create overload for IsLessThan() and IsGreaterThan() too.

[arekbal]

@paw3lx That would be also useful with BeginDate/EndDate/BeginTime/EndTime validations where one have to predate the other.
But, wouldn't adding another overload to Ensure() with another argument(model) achieve the same with somehow cleaner syntax? Like
.Ensure(m => m.RePassword, (_, m) => _.IsEqualTo(m.Password))

Or both could be made available but I think promoting single 'best' way of doing stuff is the right idea.

BTW. I don't like underscore arg names in our code and in examples. Because: "That is a convention used when you don't care about the parameter.".
https://stackoverflow.com/questions/2778362/what-does-this-mean-in-lambda-expressions

[paw3lx]

@GooRiOn What do you think about @arekbal syntax?

[GooRiOn]

I'd go for Arek's suggestion mostly because that is fairly simple to implement and does what it should. I also agree that we should promote "best way" of doing something instead of "couple fine" ways. The only problem I have is that the old syntax will be depricated (at the second version) :D

On the one hand we don't have a lot of "fame" right now so "the soon the better". But on the other, it could piss off all folks that use that.

@dbarwikowski I summon you !