fold package:turtle
Use a
Fold to reduce the stream of
a's produced by a
Shell
Efficient representation of a left fold that preserves the fold's step
function, initial accumulator, and extraction function
This allows the
Applicative instance to assemble derived folds
that traverse the container only once
A '
Fold a b' processes elements of type
a and results in
a value of type
b.
Fold step initial extract
Use a
FoldM IO to reduce the stream of
a's produced by a
Shell
Like
Fold, but monadic.
A '
FoldM m a b' processes elements of type
a and results
in a monadic value of type
m b.
FoldM step initial extract
This is similar to
FoldM IO except that the
begin field is pure
This small difference is necessary to implement a well-behaved
MonadCatch instance for
Shell
Provided for backwards compatibility with versions of
turtle-1.4.* and older