Next Haskell

What changes would we want to make to Haskell, but we can’t for fear of breaking backwards compatibility? They should instead be made to the Next Haskell.

• Better names for data, type and newtype: https://mail.haskell.org/pipermail/haskell-cafe/2015-August/120732.html

• main :: IO (); main = ... involves duplication. This needs to be got rid of, but I can’t think of a good way right now.

• Reduce special syntax: no special syntax for list types or list literals, maybe not even for tuple types or tuple literals! (->) should not be a reserved identifier.

• Either do notation or comprehensions, not both.

• Remove if. The only version of case should be a “lambda case”. Any arguments can be passed to it using the normal means of function application.

• It should be possible to “eta-reduce case branches”. That is, I should be able to write

  \case
      Just    -> foo
      Nothing -> bar

  instead of

  \case
      Just x  -> foo x
       Nothing -> bar

• Either arguments should be taken on the left hand side of a function, or the function type constructor should be reversed.

• No unary function - for negation.

• : and :: should be swapped

• No partial record fields

• x `f` y should desugar to f y x

• Warnings that should be errors

  • Missing patterns

  • Missing record fields

• Get rid of otherwise. It’s far too cute.

Sources of ideas

• https://www.reddit.com/r/haskell/comments/4f47ou/why_does_haskell_in_your_opinion_suck/