Migrate core exports from BasicPrelude to CorePrelude about basic-prelude HOT 6 CLOSED

I'm not sure about the read/show stuff. I like read/show, but it seems like maybe they don't really belong in CorePrelude.

I do agree with the rest of these, though.

from basic-prelude.

Some things that might be nice:

• Data.Ord.ordering
• Data.Char.is*

from basic-prelude.

Ooh, and maybe Data.Function.on

from basic-prelude.

I agree with @singpolyma about read/show stuff. I like everything else @DanBurton mentioned, and also like ordering and on. I'm on the fence, however, with the is* functions. It's definitely convenient, but may be encouraging a bad practice (treating textual data one character at a time, which isn't always Unicode-aware).

from basic-prelude.

I've added $!, seq, curry, until, asTypeOf, undefined, on, comparing, and equating to CorePrelude.

I was under the impression that Data.Ord.ordering existed, and functioned like its maybe and either counterparts, but apparently it does not. Should we add it?

ordering :: a -> a -> a -> Ordering -> a
ordering lt eq gt o = case o of
  LT -> lt; EQ -> eq; GT -> gt

The type Ordering is already exported.

from basic-prelude.

I can't say I've ever been writing code where I wanted a function like ordering, so it doesn't seem very generally useful to me. I'd go further and say it's problematic: it's far too easy to swap the lt and eq arguments, for example, as opposed to maybe and either, where the types will (generally) prevent you from making such a mistake.

from basic-prelude.