Unify error messaging

[nicola-bastianello]

the coercion dunders mentioned in #9 should raise a ValueError when they are applied to a non-scalar array. it would be ideal if the error message that is raised is uniform across all frameworks

currently, this is manually implemented (e.g. ValueError(f"diagonal requires a 2-D array, got {x.value.ndim}-D") in diagonal)

I suggest looking for a way that we can define the error messages only once, e.g. in an Enum, and then call them from the methods as needed. this also means swallowing framework-native errors and "replacing" them with our custom messages

if these error messages are f-strings, we could define them as lambda functions returning f-strings msg = lambda x: f"diagonal requires a 2-D array, got {x}-D" or something similar

[Simpag]

We can use try-catch blocks at the iop layer and implement all exceptions there. However, there might be some framework specific errors that are raised. This will be somewhat tricky to solve in a clean way since the errors may vary between frameworks

[nicola-bastianello]

yes, there is definitely variation on the exceptions that are raised, I've already encountered this when looking at how bool and other coercions are handled.

I'll think a bit more about this. it would be nice to have something like abstract exceptions that need to be implemented in each backend (inside there we can use try-catch tailored to the framework). but it looks like exceptions don't play nicely with abc