Provide lens compatible typeclasses. about acid-state

[dag]

Note that you can write

addEntry :: String -> Update Foo ()
addEntry s = bar %= insert s 0

[fhaust]

I know, but given that the State type is probably quite complex a Zoomed instance might be useful.

[dag]

How about

addEntry :: String -> Update Foo ()
addEntry s = state $ runState $ zoom bar $ modify $ insert s 0

I agree it would be nice if it could work with zoom directly, but anyway.

[fhaust]

Also true ... but hey ... so much words :)

[stepcut]

I don't see a way to provide a Zoomed instance with out depending on lens -- and depending on lens is a pretty big dependency for something most people will not actually use. If we can make an acid-state-lens package, that seems better. Apparently that might involve exporting some internals from acid-state?

[adamgundry]

Since f6bd2c6 exposes the definition of Update, it should be possible to write an orphan Zoomed instance downstream. Given that we don't want acid-state to depend on lens, I don't think there is anything else we can do. If someone wants to make an acid-state-lens package, feel free (though there is a bigger reorganisation pending, see #99).

[fhaust]

Oh ... it's been a while :-)

I think you can write lens instances without depending on the lens package, but honestly I don't care anymore.