Copyright | (c) 2012--2014 The University of Kansas |
---|---|

License | BSD3 |

Maintainer | Neil Sculthorpe <neil@ittc.ku.edu> |

Stability | beta |

Portability | ghc |

Safe Haskell | None |

Language | Haskell2010 |

This module provides combinators that traverse a tree.

Note that all traversals take place on the node, its children, or its descendents. Deliberately, there is no mechanism for "ascending" the tree.

- class Walker c u where
- allR :: MonadCatch m => Rewrite c m u -> Rewrite c m u
- allT :: (MonadCatch m, Monoid b) => Transform c m u b -> Transform c m u b
- oneT :: MonadCatch m => Transform c m u b -> Transform c m u b
- anyR :: MonadCatch m => Rewrite c m u -> Rewrite c m u
- oneR :: MonadCatch m => Rewrite c m u -> Rewrite c m u
- childL :: (ReadPath c crumb, Eq crumb, MonadCatch m) => crumb -> Lens c m u u

- childR :: (ReadPath c crumb, Eq crumb, Walker c u, MonadCatch m) => crumb -> Rewrite c m u -> Rewrite c m u
- childT :: (ReadPath c crumb, Eq crumb, Walker c u, MonadCatch m) => crumb -> Transform c m u b -> Transform c m u b
- alltdR :: (Walker c u, MonadCatch m) => Rewrite c m u -> Rewrite c m u
- allbuR :: (Walker c u, MonadCatch m) => Rewrite c m u -> Rewrite c m u
- allduR :: (Walker c u, MonadCatch m) => Rewrite c m u -> Rewrite c m u
- anytdR :: (Walker c u, MonadCatch m) => Rewrite c m u -> Rewrite c m u
- anybuR :: (Walker c u, MonadCatch m) => Rewrite c m u -> Rewrite c m u
- anyduR :: (Walker c u, MonadCatch m) => Rewrite c m u -> Rewrite c m u
- onetdR :: (Walker c u, MonadCatch m) => Rewrite c m u -> Rewrite c m u
- onebuR :: (Walker c u, MonadCatch m) => Rewrite c m u -> Rewrite c m u
- prunetdR :: (Walker c u, MonadCatch m) => Rewrite c m u -> Rewrite c m u
- innermostR :: (Walker c u, MonadCatch m) => Rewrite c m u -> Rewrite c m u
- allLargestR :: (Walker c u, MonadCatch m) => Transform c m u Bool -> Rewrite c m u -> Rewrite c m u
- anyLargestR :: (Walker c u, MonadCatch m) => Transform c m u Bool -> Rewrite c m u -> Rewrite c m u
- oneLargestR :: (Walker c u, MonadCatch m) => Transform c m u Bool -> Rewrite c m u -> Rewrite c m u
- foldtdT :: (Walker c u, MonadCatch m, Monoid b) => Transform c m u b -> Transform c m u b
- foldbuT :: (Walker c u, MonadCatch m, Monoid b) => Transform c m u b -> Transform c m u b
- onetdT :: (Walker c u, MonadCatch m) => Transform c m u b -> Transform c m u b
- onebuT :: (Walker c u, MonadCatch m) => Transform c m u b -> Transform c m u b
- prunetdT :: (Walker c u, MonadCatch m, Monoid b) => Transform c m u b -> Transform c m u b
- crushtdT :: (Walker c u, MonadCatch m, Monoid b) => Transform c m u b -> Transform c m u b
- crushbuT :: (Walker c u, MonadCatch m, Monoid b) => Transform c m u b -> Transform c m u b
- collectT :: (Walker c u, MonadCatch m) => Transform c m u b -> Transform c m u [b]
- collectPruneT :: (Walker c u, MonadCatch m) => Transform c m u b -> Transform c m u [b]
- allLargestT :: (Walker c u, MonadCatch m, Monoid b) => Transform c m u Bool -> Transform c m u b -> Transform c m u b
- oneLargestT :: (Walker c u, MonadCatch m) => Transform c m u Bool -> Transform c m u b -> Transform c m u b
- childrenT :: (ReadPath c crumb, Walker c u, MonadCatch m) => Transform c m u [crumb]
- summandIsTypeT :: forall c m a u. (MonadCatch m, Injection a u) => a -> Transform c m u Bool
- pathL :: (ReadPath c crumb, Eq crumb, Walker c u, MonadCatch m) => Path crumb -> Lens c m u u
- localPathL :: (ReadPath c crumb, Eq crumb, Walker c u, MonadCatch m) => LocalPath crumb -> Lens c m u u
- exhaustPathL :: (ReadPath c crumb, Eq crumb, Walker c u, MonadCatch m) => Path crumb -> Lens c m u u
- repeatPathL :: (ReadPath c crumb, Eq crumb, Walker c u, MonadCatch m) => Path crumb -> Lens c m u u
- pathR :: (ReadPath c crumb, Eq crumb, Walker c u, MonadCatch m) => Path crumb -> Rewrite c m u -> Rewrite c m u
- pathT :: (ReadPath c crumb, Eq crumb, Walker c u, MonadCatch m) => Path crumb -> Transform c m u b -> Transform c m u b
- localPathR :: (ReadPath c crumb, Eq crumb, Walker c u, MonadCatch m) => LocalPath crumb -> Rewrite c m u -> Rewrite c m u
- localPathT :: (ReadPath c crumb, Eq crumb, Walker c u, MonadCatch m) => LocalPath crumb -> Transform c m u b -> Transform c m u b
- testPathT :: (ReadPath c crumb, Eq crumb, Walker c u, MonadCatch m) => Path crumb -> Transform c m u Bool

# Shallow Traversals

## Tree Walkers

`Walker`

captures the ability to walk over a tree containing nodes of type `u`

,
using a specific context `c`

.

Minimal complete definition: `allR`

.

Default definitions are provided for `anyR`

, `oneR`

, `allT`

, `oneT`

, and `childL`

,
but they may be overridden for efficiency.

allR :: MonadCatch m => Rewrite c m u -> Rewrite c m u Source

Apply a rewrite to all immediate children, succeeding if they all succeed.

allT :: (MonadCatch m, Monoid b) => Transform c m u b -> Transform c m u b Source

Apply a transformation to all immediate children, succeeding if they all succeed.
The results are combined in a `Monoid`

.

oneT :: MonadCatch m => Transform c m u b -> Transform c m u b Source

Apply a transformation to the first immediate child for which it can succeed.

anyR :: MonadCatch m => Rewrite c m u -> Rewrite c m u Source

Apply a rewrite to all immediate children, suceeding if any succeed.

oneR :: MonadCatch m => Rewrite c m u -> Rewrite c m u Source

Apply a rewrite to the first immediate child for which it can succeed.

childL :: (ReadPath c crumb, Eq crumb, MonadCatch m) => crumb -> Lens c m u u Source

Construct a `Lens`

to the n-th child node.

Typeable (* -> * -> Constraint) Walker |

## Child Transformations

childR :: (ReadPath c crumb, Eq crumb, Walker c u, MonadCatch m) => crumb -> Rewrite c m u -> Rewrite c m u Source

Apply a rewrite to a specified child.

childT :: (ReadPath c crumb, Eq crumb, Walker c u, MonadCatch m) => crumb -> Transform c m u b -> Transform c m u b Source

Apply a transformation to a specified child.

# Deep Traversals

## Traversals for Rewrites

alltdR :: (Walker c u, MonadCatch m) => Rewrite c m u -> Rewrite c m u Source

Apply a rewrite in a top-down manner, succeeding if they all succeed.

allbuR :: (Walker c u, MonadCatch m) => Rewrite c m u -> Rewrite c m u Source

Apply a rewrite in a bottom-up manner, succeeding if they all succeed.

allduR :: (Walker c u, MonadCatch m) => Rewrite c m u -> Rewrite c m u Source

Apply a rewrite twice, in a top-down and bottom-up way, using one single tree traversal, succeeding if they all succeed.

anytdR :: (Walker c u, MonadCatch m) => Rewrite c m u -> Rewrite c m u Source

Apply a rewrite in a top-down manner, succeeding if any succeed.

anybuR :: (Walker c u, MonadCatch m) => Rewrite c m u -> Rewrite c m u Source

Apply a rewrite in a bottom-up manner, succeeding if any succeed.

anyduR :: (Walker c u, MonadCatch m) => Rewrite c m u -> Rewrite c m u Source

Apply a rewrite twice, in a top-down and bottom-up way, using one single tree traversal, succeeding if any succeed.

onetdR :: (Walker c u, MonadCatch m) => Rewrite c m u -> Rewrite c m u Source

Apply a rewrite to the first node for which it can succeed, in a top-down traversal.

onebuR :: (Walker c u, MonadCatch m) => Rewrite c m u -> Rewrite c m u Source

Apply a rewrite to the first node for which it can succeed, in a bottom-up traversal.

prunetdR :: (Walker c u, MonadCatch m) => Rewrite c m u -> Rewrite c m u Source

Attempt to apply a `Rewrite`

in a top-down manner, pruning at successful rewrites.

innermostR :: (Walker c u, MonadCatch m) => Rewrite c m u -> Rewrite c m u Source

A fixed-point traveral, starting with the innermost term.

allLargestR :: (Walker c u, MonadCatch m) => Transform c m u Bool -> Rewrite c m u -> Rewrite c m u Source

Apply a rewrite to the largest node(s) that satisfy the predicate, requiring all to succeed.

anyLargestR :: (Walker c u, MonadCatch m) => Transform c m u Bool -> Rewrite c m u -> Rewrite c m u Source

Apply a rewrite to the largest node(s) that satisfy the predicate, succeeding if any succeed.

oneLargestR :: (Walker c u, MonadCatch m) => Transform c m u Bool -> Rewrite c m u -> Rewrite c m u Source

Apply a rewrite to the first node for which it can succeed among the largest node(s) that satisfy the predicate.

## Traversals for Transformations

foldtdT :: (Walker c u, MonadCatch m, Monoid b) => Transform c m u b -> Transform c m u b Source

Fold a tree in a top-down manner, using a single `Transform`

for each node.

foldbuT :: (Walker c u, MonadCatch m, Monoid b) => Transform c m u b -> Transform c m u b Source

Fold a tree in a bottom-up manner, using a single `Transform`

for each node.

onetdT :: (Walker c u, MonadCatch m) => Transform c m u b -> Transform c m u b Source

Apply a transformation to the first node for which it can succeed, in a top-down traversal.

onebuT :: (Walker c u, MonadCatch m) => Transform c m u b -> Transform c m u b Source

Apply a transformation to the first node for which it can succeed, in a bottom-up traversal.

prunetdT :: (Walker c u, MonadCatch m, Monoid b) => Transform c m u b -> Transform c m u b Source

Attempt to apply a `Transform`

in a top-down manner, pruning at successes.

crushtdT :: (Walker c u, MonadCatch m, Monoid b) => Transform c m u b -> Transform c m u b Source

An always successful top-down fold, replacing failures with `mempty`

.

crushbuT :: (Walker c u, MonadCatch m, Monoid b) => Transform c m u b -> Transform c m u b Source

An always successful bottom-up fold, replacing failures with `mempty`

.

collectT :: (Walker c u, MonadCatch m) => Transform c m u b -> Transform c m u [b] Source

An always successful traversal that collects the results of all successful applications of a `Transform`

in a list.

collectPruneT :: (Walker c u, MonadCatch m) => Transform c m u b -> Transform c m u [b] Source

Like `collectT`

, but does not traverse below successes.

allLargestT :: (Walker c u, MonadCatch m, Monoid b) => Transform c m u Bool -> Transform c m u b -> Transform c m u b Source

Apply a transformation to the largest node(s) that satisfy the predicate, combining the results in a monoid.

oneLargestT :: (Walker c u, MonadCatch m) => Transform c m u Bool -> Transform c m u b -> Transform c m u b Source

Apply a transformation to the first node for which it can succeed among the largest node(s) that satisfy the predicate.

# Utilitity Transformations

childrenT :: (ReadPath c crumb, Walker c u, MonadCatch m) => Transform c m u [crumb] Source

List the children of the current node.

summandIsTypeT :: forall c m a u. (MonadCatch m, Injection a u) => a -> Transform c m u Bool Source

Test if the type of the current node summand matches the type of the argument.
Note that the argument *value* is never inspected, it is merely a proxy for a type argument.

# Paths

## Building Lenses from Paths

pathL :: (ReadPath c crumb, Eq crumb, Walker c u, MonadCatch m) => Path crumb -> Lens c m u u Source

localPathL :: (ReadPath c crumb, Eq crumb, Walker c u, MonadCatch m) => LocalPath crumb -> Lens c m u u Source

exhaustPathL :: (ReadPath c crumb, Eq crumb, Walker c u, MonadCatch m) => Path crumb -> Lens c m u u Source

repeatPathL :: (ReadPath c crumb, Eq crumb, Walker c u, MonadCatch m) => Path crumb -> Lens c m u u Source

Repeat as many iterations of the `Path`

as possible.

## Applying transformations at the end of Paths

pathR :: (ReadPath c crumb, Eq crumb, Walker c u, MonadCatch m) => Path crumb -> Rewrite c m u -> Rewrite c m u Source

Apply a rewrite at a point specified by a `Path`

.

pathT :: (ReadPath c crumb, Eq crumb, Walker c u, MonadCatch m) => Path crumb -> Transform c m u b -> Transform c m u b Source

Apply a transformation at a point specified by a `Path`

.

localPathR :: (ReadPath c crumb, Eq crumb, Walker c u, MonadCatch m) => LocalPath crumb -> Rewrite c m u -> Rewrite c m u Source

Apply a rewrite at a point specified by a `LocalPath`

.

localPathT :: (ReadPath c crumb, Eq crumb, Walker c u, MonadCatch m) => LocalPath crumb -> Transform c m u b -> Transform c m u b Source

Apply a transformation at a point specified by a `LocalPath`

.