Implement IEqualityComparer<Expression?> and GetHashCode

[SpaceOgre]

Hi,

I know this library is pretty old but I stumbled upon it when looking for a way to compare Expressions from diffrent Classes but with the same value.

I have a need for GetHashCode when doing this and wonder if you think it would be hard to implement it for this comparer? It would be great to be able to use it with HashSet, Distinct etc

I have looked at the Microsofts ExpressionEqualityComparer and tweak their version with your TryCalculateConstant and it seems to work but I have only tested it with a small number of expressions. If you are intrestead I could look into adding theirs GetHashCode for this library.

[nullptre]

Hi. I recall I was thinking about that long time ago too. Feel free to add, any contribution is appreciated.

[nullptre]

BTW, there are some plans to refresh the code and finally port to .net7 however free time is limited for me now.