So I would love to have tho following type class:
class Display a where display :: a -> String default display :: Show a => a -> String display = show
Note that for many Prelude types `show == display`, with the notable exception of String, where `display = id`. One use case where this matters is string interpolation [1][2][3].
I would also like a class like that to exist.
But I think it should be based on Text and Text builder rather than String (and hence be outside of base).
I created an initial draft: https://github.com/sol/display/blob/master/src/Data/Display.hs I named the builder version `displayBuilder` as I could not come up with any better name (suggestions much appreciated!). In addition, I think the `display` method has to be outside of the class. Otherwise, if somebody defines `display` he end up with the default implementation of `displayBuilder` (which is based on show and may not be what is intended). Any input on that? Pleas bikeshed hard! Cheers, Simon