Maintainer | Ralf Laemmel, Joost Visser |
---|---|

Stability | experimental |

Portability | portable |

Safe Haskell | None |

Language | Haskell98 |

This module is part of `StrategyLib`

, a library of functional strategy
combinators, including combinators for generic traversal. This module
is basically a wrapper for the strategy primitives plus some extra
basic strategy combinators that can be defined immediately in terms
of the primitive ones.

- module Data.Generics.Strafunski.StrategyLib.Models.Deriving.StrategyPrimitives
- idTP :: Monad m => TP m
- failTP :: MonadPlus m => TP m
- failTU :: MonadPlus m => TU a m
- constTU :: Monad m => a -> TU a m
- compTU :: Monad m => m a -> TU a m
- monoTP :: (Term a, MonadPlus m) => (a -> m a) -> TP m
- monoTU :: (Term a, MonadPlus m) => (a -> m b) -> TU b m
- dotTU :: Monad m => (a -> b) -> TU a m -> TU b m
- op2TU :: Monad m => (a -> b -> c) -> TU a m -> TU b m -> TU c m
- voidTP :: Monad m => TP m -> TU () m
- voidTU :: Monad m => TU u m -> TU () m
- con :: MonadPlus m => TP m
- com :: MonadPlus m => TP m

# Documentation

# Useful defaults for strategy update (see `adhocTU`

and `adhocTP`

).

failTP :: MonadPlus m => TP m Source

Type-preserving failure. Always fails, independent of the incoming
term. Uses `MonadPlus`

to model partiality.

failTU :: MonadPlus m => TU a m Source

Type-unifying failure. Always fails, independent of the incoming
term. Uses `MonadPlus`

to model partiality.

constTU :: Monad m => a -> TU a m Source

Type-unifying constant strategy. Always returns the argument value `a`

,
independent of the incoming term.

compTU :: Monad m => m a -> TU a m Source

Type-unifying monadic constant strategy. Always performs the argument
computation `a`

, independent of the incoming term. This is a monadic
variation of `constTU`

.

# Lift a function to a strategy type with failure as default

monoTP :: (Term a, MonadPlus m) => (a -> m a) -> TP m Source

Apply the monomorphic, type-preserving argument function, if its input type matches the input term's type. Otherwise, fail.

monoTU :: (Term a, MonadPlus m) => (a -> m b) -> TU b m Source

Apply the monomorphic, type-unifying argument function, if its input type matches the input term's type. Otherwise, fail.

# Function composition

dotTU :: Monad m => (a -> b) -> TU a m -> TU b m Source

Sequential ccomposition of monomorphic function and type-unifying strategy.
In other words, after the type-unifying strategy `s`

has been applied,
the monomorphic function `f`

is applied to the resulting value.

op2TU :: Monad m => (a -> b -> c) -> TU a m -> TU b m -> TU c m Source

Parallel combination of two type-unifying strategies with a binary
combinator. In other words, the values resulting from applying the
type-unifying strategies are combined to a final value by applying
the combinator `o`

.

# Reduce a strategy's performance to its effects

voidTP :: Monad m => TP m -> TU () m Source

Reduce a type-preserving strategy to a type-unifying one that ignores its result term and returns void, but retains its monadic effects.

voidTU :: Monad m => TU u m -> TU () m Source

Reduce a type-unifying strategy to a type-unifying one that ignores its result value and returns void, but retains its monadic effects.