[C#] Add exercise User-defined Exceptions

[mikedamay]

1. Please review UserDefinedExceptions.cs as part of your initial review of this draft.
2. @ErikSchierboom I know you are averse to including language features in the test file that are not pre-requisites for the exercise. We need lambdas in the test file but I don't really want to increase the dependency count. I did half the Haskell track without really understanding how the test framework worked so I'm not so committed to this principle as you. However, I am happy to fall into line if necessary.
3. I was in two minds about whether to include less boilerplate in the code provided for CalculationException but decided against it on the grounds that it could multiply the number of representations required. I can't really judge

[mikedamay]

I have marked 4 suggestions A), B), C) and D) in the review comments. These all amount to the same thing to a greater or lesser extent. My choice is for simplicity. I don't think the proposed changes add much to the features of user defined exceptions exercised here although they make the code a little more natural and the story a bit more realistic.

I am happy to make the suggested changes but I don't see why you come down in favour of naturalness/realism rather than simplicity. Particularly as the whole thing is artificial in the first place. To effectively do reviews myself I need to know the criteria otherwise it will put more of a burden on you.

While we are at the draft review stage you can safely skip obvious "errors" like CalculationException_template if you want (although I'm always grateful to have typos picked up). This sort of review seems to be more about the big picture.

[ErikSchierboom]

I have marked 4 suggestions A), B), C) and D) in the review comments.

I don't see them marked, but I assume you are referring to the four open comments?

While we are at the draft review stage you can safely skip obvious "errors" like CalculationException_template if you want (although I'm always grateful to have typos picked up). This sort of review seems to be more about the big picture.

It is. I just couldn't help myself :)

[mikedamay]

It is. I just couldn't help myself :)

Fair enough. Certainly no problem for me.

I don't see them marked, but I assume you are referring to the four open comments?

Yes the open comments. You will see the letters there.

[ErikSchierboom]

Yes the open comments. You will see the letters there.

I don't see them :)

[mikedamay]

Sorry. did it again - ignored PENDING.

You should see them now.

[mikedamay]

yep - ready to review

[ErikSchierboom]

Brilliant! Thanks for adding this exercise!

[mikedamay]

I think we should have sliced up the functionality differently putting the wrapping in the calculator class and the filtering in test harness. I think it would make marginally more sense. I may revisit it after we have done the first 42.

[ErikSchierboom]

I think we should have sliced up the functionality differently putting the wrapping in the calculator class and the filtering in test harness. I think it would make marginally more sense. I may revisit it after we have done the first 42.

Ah that would have been nice indeed. Maybe you could create an issue for it? It sounds like this would be nice an an improve issue :)

[mikedamay]

See #1664