| Maintainer | Ralf Laemmel, Joost Visser |
|---|---|
| Stability | experimental |
| Portability | portable |
| Safe Haskell | None |
| Language | Haskell98 |
Data.Generics.Strafunski.StrategyLib.FlowTheme
Contents
- Try: recover from failure
- Test: ignore result, but retain effects
- If-then-else: pass value from condition to then-clause
- If-then: disciplined form of a guarding
- Not: negation by failure
- Exclusive choice
- Generic filter, derived from monomorphic predicate
- Generic ticker, derived from monomorphic predicate
- Type guards
- Generic ticker, derived from type guard
- Generic filters, derived from type guard
Description
This module is part of StrategyLib, a library of functional strategy
combinators, including combinators for generic traversal. This module
defines combinators to wire up control and data flow. Whenever possible,
we define the combinators in an overloaded fashion but we provide
type-specialised variants for TP and TU for convenience.
- tryS :: (StrategyPlus s m, StrategyMonoid s m) => s m -> s m
- tryTP :: MonadPlus m => TP m -> TP m
- tryTU :: (MonadPlus m, Monoid u) => TU u m -> TU u m
- testS :: Strategy s m => s m -> TP m
- testTP :: Monad m => TP m -> TP m
- testTU :: Monad m => TU a m -> TP m
- ifS :: StrategyPlus s m => TU u m -> (u -> s m) -> s m -> s m
- ifTP :: MonadPlus m => TU u m -> (u -> TP m) -> TP m -> TP m
- ifTU :: MonadPlus m => TU u m -> (u -> TU u' m) -> TU u' m -> TU u' m
- ifthenS :: Strategy s m => TU () m -> s m -> s m
- ifthenTP :: Monad m => TU () m -> TP m -> TP m
- ifthenTU :: Monad m => TU () m -> TU u m -> TU u m
- notS :: StrategyPlus s m => s m -> TP m
- notTP :: MonadPlus m => TP m -> TP m
- notTU :: MonadPlus m => TU u m -> TP m
- xchoiceS :: StrategyPlus s m => s m -> s m -> s m
- xchoiceTP :: MonadPlus m => TP m -> TP m -> TP m
- xchoiceTU :: MonadPlus m => TU u m -> TU u m -> TU u m
- filterTP :: (Term t, MonadPlus m) => (t -> Bool) -> TP m
- filterTU :: (Term t, MonadPlus m) => (t -> Bool) -> TU t m
- tickTU :: (Monad m, Term t, Num n) => (t -> Bool) -> TU n m
- type TypeGuard a = a -> ()
- typeGuard :: TypeGuard a
- typeTickTU :: (Term t, Monad m, Num n) => TypeGuard t -> TU n m
- typeFilterTP :: (Term t, MonadPlus m) => TypeGuard t -> TP m
- typeFilterTU :: (Term t, MonadPlus m) => TypeGuard t -> TU t m
Try: recover from failure
tryS :: (StrategyPlus s m, StrategyMonoid s m) => s m -> s m Source
Attempt a strategy s, but recover if it fails.
tryTP :: MonadPlus m => TP m -> TP m Source
Attempt a type-preserving strategy s, but if it fails, return the
input term unchanged.
Test: ignore result, but retain effects
testS :: Strategy s m => s m -> TP m Source
Test for a strategy's success in a type-preserving context.
testTP :: Monad m => TP m -> TP m Source
Test for a type-preserving strategy's success in a type-preserving context.
testTU :: Monad m => TU a m -> TP m Source
Test for a type-unifying strategy's success in a type-preserving context.
If-then-else: pass value from condition to then-clause
ifS :: StrategyPlus s m => TU u m -> (u -> s m) -> s m -> s m Source
If c succeeds, pass its value to the then-clause t,
otherwise revert to the else-clause e.
ifTP :: MonadPlus m => TU u m -> (u -> TP m) -> TP m -> TP m Source
If c succeeds, pass its value to the then-clause t,
otherwise revert to the else-clause e.
ifTU :: MonadPlus m => TU u m -> (u -> TU u' m) -> TU u' m -> TU u' m Source
If c succeeds, pass its value to the then-clause t,
otherwise revert to the else-clause e.
If-then: disciplined form of a guarding
ifthenS :: Strategy s m => TU () m -> s m -> s m Source
Guard then-clause t by the void-valued type-unifying
condition c.
ifthenTP :: Monad m => TU () m -> TP m -> TP m Source
Guard type-preserving then-clause t by the void-valued type-unifying
condition c.
ifthenTU :: Monad m => TU () m -> TU u m -> TU u m Source
Guard type-unifying then-clause t by the void-valued type-unifying
condition c.
Not: negation by failure
notS :: StrategyPlus s m => s m -> TP m Source
Invert the success-value of strategy s.
notTP :: MonadPlus m => TP m -> TP m Source
Invert the success-value of type-preserving strategy s. Its output
term (in case of success) will be ignored.
notTU :: MonadPlus m => TU u m -> TP m Source
Invert the success-value of type-unifying strategy s. Its output
value (in case of success) will be ignored.
Exclusive choice
xchoiceS :: StrategyPlus s m => s m -> s m -> s m Source
Succeed if exactly one argument strategy succeeds.
xchoiceTP :: MonadPlus m => TP m -> TP m -> TP m Source
Succeed if exactly one argument strategy succeeds.
xchoiceTU :: MonadPlus m => TU u m -> TU u m -> TU u m Source
Succeed if exactly one argument strategy succeeds.
Generic filter, derived from monomorphic predicate
filterTP :: (Term t, MonadPlus m) => (t -> Bool) -> TP m Source
If predicate g holds for the input term, return it as output term,
otherwise fail.
filterTU :: (Term t, MonadPlus m) => (t -> Bool) -> TU t m Source
If predicate g holds for the input term, return it as output value,
otherwise fail.
Generic ticker, derived from monomorphic predicate
tickTU :: (Monad m, Term t, Num n) => (t -> Bool) -> TU n m Source
If predicate g holds for the input term,
return 1 otherwise return 0.
Type guards
type TypeGuard a = a -> () Source
Type guard (function type), i.e., guard that does not observe values
typeGuard :: TypeGuard a Source
Type guard (function). Typical usage:
full_tdTU (typeTickTU (typeGuard::TypeGuard MyType))
Generic ticker, derived from type guard
typeTickTU :: (Term t, Monad m, Num n) => TypeGuard t -> TU n m Source
If type guard holds for the input term, return 1 otherwise return 0.