Add Applicative instances for MTL types

Bas van Dijk v.dijk.bas at
Sat Dec 20 13:09:49 EST 2008


In a project of mine I needed an Applicative instance for Identity and
noticed it didn't exist. So I decided to add Applicative (and
Alternative instances where possible) for all MTL types.

When I was about to submit a library proposal I saw there already
existed one. So I added my patch to that ticket.

My patch I different in that my Applicative instances don't require a
Monad constraint. This also means that most Functor instances now also
depend on Applicative rather than on Monad.

See the ticket for the details:

Discussion period: 5 weeks (taking the holidays into account)

This is the old thread about this proposal:



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