Preview media types

[phadej]

No description provided.

[phadej]

Note: If one would need a bunch of different preview content types, then writing a

data MyPreviewTypes = A | B | C

data P (p :: MyPreviewTypes)

instance PreviewAccept (P 'A) where ...
instance PreviewAccept (P 'B) where ...
instance PreviewAccept (P 'C) where ...

would work. It's a bit roundabout, but better than making GenRequest polykinded.

EDIT: Yet, now as I think about it, this is little different then separate types. You cannot put different content-types requests into a list anyway, without some existential thingie, at which point it's somewhat irrelevant; maybe.