put if statements within type constraints http://github.com/mikeizbicki/ifcxt
|Latest on Hackage:||0.1.1|
This package is not currently in any snapshots. If you're interested in using it, we recommend adding it to Stackage Nightly. Doing so will make builds more reliable, and allow stackage.org to host generated Haddocks.
This package introduces the
which lets your write if statements that depend on a polymorphic variable's class instances.
For example, we can make a version of
show that can be called on any type:
cxtShow :: forall a. IfCxt (Show a) => a -> String cxtShow a = ifCxt (Proxy::Proxy (Show a)) (show a) "<<unshowable>>"
Running this function in ghci, we get:
cxtShow (1 :: Int)
cxtShow (id :: a -> a)
See the project webpage http://github.com/mikeizbicki/ifcxt for more details.