[Haskell-cafe] How to define Show [MyType] ?

[Ryan Ingram]

> If you really, really wanted to define Show [ShipInfo], then putting
>
> {-# LANGUAGE FlexibleInstances, OverlappingInstances #-}
>
> at the beginning of your file would work.  At the cost of using
> overlapping instances, of course.

And at the cost of causing code like this:

> f :: Show a => [a] -> String
> f xs = show xs

to fail to compile (see "Incoherent Instances").

Implement "showList"; it's the Right Answer for this case.