Data.ProtoLens.Combinators

An assorted collection of functions useful when working with ProtoLens protocol buffers. These functions are inspired by functionality found in the protobuf implementation in other languages.

Documentation

has :: Phantom f => LensLike f a a' (Maybe b) b' -> LensLike f a a' Bool b''

Turns a LensLike getting a Maybe into a Getter of a Bool that returns True when the Maybe is Just something.

I.e., makes a getter for a Maybe field that returns whether it's set.

clear :: Setter a a' b (Maybe b') -> a -> a'

Sets the provided lens in a to Nothing.

make :: Default def => State def a -> def

Creates a Default and then applies the provided State to it. This is convenient for creating complicated structures.

modifyInState :: s -> State s a -> s

Allows one to modify a value in the State monad. Note that this is just for syntactic convenience with do blocks, e.g.

   newThing = modifyInState thing $ do
       ...