Copyright | (C) 2012-2015 Edward Kmett |
---|---|
License | BSD-style (see the file LICENSE) |
Maintainer | Edward Kmett <ekmett@gmail.com> |
Stability | experimental |
Portability | non-portable |
Safe Haskell | Safe |
Language | Haskell98 |
This module provides implementation details of the combinators in
Control.Lens.Level, which provides for the breadth-first Traversal
of
an arbitrary Traversal
.
Levels
This data type represents a path-compressed copy of one level of a source data structure. We can safely use path-compression because we know the depth of the tree.
Path compression is performed by viewing a Level
as a PATRICIA trie of the
paths into the structure to leaves at a given depth, similar in many ways
to a IntMap
, but unlike a regular PATRICIA trie we do not need
to store the mask bits merely the depth of the fork.
One invariant of this structure is that underneath a Two
node you will not
find any Zero
nodes, so Zero
can only occur at the root.
TraversableWithIndex i (Level i) Source | |
FoldableWithIndex i (Level i) Source | |
FunctorWithIndex i (Level i) Source | |
Functor (Level i) Source | |
Foldable (Level i) Source | |
Traversable (Level i) Source | |
(Eq i, Eq a) => Eq (Level i a) Source | |
(Ord i, Ord a) => Ord (Level i a) Source | |
(Read i, Read a) => Read (Level i a) Source | |
(Show i, Show a) => Show (Level i a) Source |
Deepening | |
|
deepening :: i -> a -> Deepening i a Source
Generate the leaf of a given Deepening
based on whether or not we're at the correct depth.
This is an illegal Applicative
used to replace the contents of a list of consecutive Level
values
representing each layer of a structure into the original shape that they were derived from.
Attempting to Flow
something back into a shape other than the one it was taken from will fail.
Functor (Flows i b) Source | |
Applicative (Flows i b) Source | This is an illegal |
Apply (Flows i b) Source |