Idris2Doc : Control.Monad.Writer.CPS

Control.Monad.Writer.CPS

Note: The difference to a 'strict' Writer implementation is
that accumulation of values does not happen in the
Applicative and Monad instances but when invoking `Writer`-specific
functions like `writer` or `listen`.

Writer : Type -> Type -> Type

  The `return` function produces the output `neutral`, while `>>=`
  combines the outputs of the subcomputations using `<+>`.

Totality: total

record WriterT : Type -> (Type -> Type) -> Type -> Type

  A writer monad parameterized by:
  
  @w the output to accumulate.
  
  @m The inner monad.
  
  The `pure` function produces the output `neutral`, while `>>=`
  combines the outputs of the subcomputations using `<+>`.

Totality: total
Constructor:

MkWriterT : (w -> m (a, w)) -> WriterT w m a

Projection:

.unWriterT : WriterT w m a -> w -> m (a, w)

execWriter : Monoid w => Writer w a -> w

  Extract the output from a writer computation.

Totality: total

execWriterT : (Functor m, Monoid w) => WriterT w m a -> m w

  Extract the output from a writer computation.

Totality: total

mapWriter : (Monoid w, Semigroup w') => ((a, w) -> (b, w')) -> Writer w a -> Writer w' b

  Map both the return value and output of a computation using
  the given function.

Totality: total

mapWriterT : (Functor n, (Monoid w, Semigroup w')) => (m (a, w) -> n (b, w')) -> WriterT w m a -> WriterT w' n b

  Map both the return value and output of a computation using
  the given function.

Totality: total

runWriter : Monoid w => Writer w a -> (a, w)

  Unwrap a writer computation as a (result, output) pair.

Totality: total

runWriterT : Monoid w => WriterT w m a -> m (a, w)

  Unwrap a writer computation.
  (The inverse of 'writerT'.)

Totality: total

writerT : (Functor m, Semigroup w) => m (a, w) -> WriterT w m a

  Construct an writer computation from a (result,output) computation.
  (The inverse of `runWriterT`.)

Totality: total