Strafunski-StrategyLib-5.0.0.4: Library for strategic programming

Portability portable experimental Ralf Laemmel, Joost Visser None

Data.Generics.Strafunski.StrategyLib.KeyholeTheme

Description

This module is part of `StrategyLib`, a library of functional strategy combinators, including combinators for generic traversal. This module defines a number combinators for keyhole operations, i.e. for operations that have ordinary parametric or adhoc polymorhpic types, but employ strategies inside.

Synopsis

Focus

Arguments

 :: (Term f, Term t) => (f -> Maybe f) Identify focus -> t Input term -> Maybe f Focused term

Select the identified focus. Fails if no subterm can be selected.

replaceFocus :: (Term t, Term t') => (t -> Maybe t) -> t' -> Maybe t'Source

Replace the identified focus. Fails if no subterm can be replaced.

Arguments

 :: (Term f, Term [f], Term t) => (f -> Maybe f) Identify focus -> t Input term -> Maybe t Output term without focused entity

Delete the focus assuming it is an element in a list. Fails if no deletion can be performed.

Arguments

 :: (Term f, Term h, Term t) => (f -> Maybe f) Get focus -> (h -> Maybe h) Get host -> t Input term -> Maybe h Located host

Find the host of the focused entity, i.e. a superterm of the focussed subterm.

Arguments

 :: (Term f, Term h, Term t) => (f -> Bool) Test focus -> (h -> h) Wrap host -> t Input term -> Maybe t Output term

Listification

listify :: (Term x, Term y) => x -> [y]Source

Put all nodes of a certain type into a list.

strings :: Term x => x -> [String]Source

Put all nodes of type `String` into a list. This is a type-specialization of `listify`.

Keyhole versions of basic strategy combinators.

inj :: (MonadPlus m, Term x, Term c) => (c -> m c) -> x -> m xSource

Apply the argument function to the unique subterm of the input term. Fail if the input term has more subterms or if the subterm is not of the appropriate type. This is a keyhole version of the traversal combinator `injTP`