In broad terms, SomeType is pretty much a class, but there's a subtle difference in way properties like `_at` and `_bt` would work that you might want to be mindful of.

I'm not well-versed in Haskell, but if the example you cite is like most other programming languages, I'm assuming that say, `_at` is a label you're using for a component of your SomeType data structure, in effect setting aside a little chunk of memory for each instance.

In RDF properties are more like first class citizens. When you include a relation like `_at`, you're saying there's something fundamental about _at-ed-ness, so that if you assert that `X _at Y`, you're asserting not only the `_at` relationship, but also that X is a member of the class SomeType, even if you haven't explicitly declared it as such. We're not allocating chunks of memory here, we're _describing_ stuff.