Vgrep.Event

Event handling

An event handler is a function

handleEvent :: MonadState s m => e -> s -> Next (m Redraw)

where e is the event type and s is the state of the handler. The Next type determines the type of action to be performed. The state s is passed as a parameter so the handler can decide which type of action to perform, while not being able to modify the state.

Event handlers form a Monoid where the first handler that triggers will perform the action:

(handleSome <> handleOther) event state

is identical to

case handleSome event state of
    Skip -> handleOther event state
    action -> action

data Next a

The type of action to be performed on an event.

Constructors

Skip

Do not handle the event (fall-through to other event handlers)

Continue a

Handle the event by performing an action

Interrupt Interrupt

Interrupt the application

Instances

Functor Next

Defined in Vgrep.Event

Methods

fmap :: (a -> b) -> Next a -> Next b

(<$) :: a -> Next b -> Next a

Semigroup (Next a)

The first event handler that triggers (i. e. does not return Skip) handles the event.

Defined in Vgrep.Event

Methods

(<>) :: Next a -> Next a -> Next a

sconcat :: NonEmpty (Next a) -> Next a

stimes :: Integral b => b -> Next a -> Next a

Monoid (Next a)

Defined in Vgrep.Event

Methods

mempty :: Next a

mappend :: Next a -> Next a -> Next a

mconcat :: [Next a] -> Next a

data Redraw

Constructors

Redraw

Indicates that the state has been changed visibly, so the screen should be refreshed.

Unchanged

The state has not changed or the change would not be visible, so refreshing the screen is not required.

Instances

Semigroup Redraw

Defined in Vgrep.Event

Methods

(<>) :: Redraw -> Redraw -> Redraw

sconcat :: NonEmpty Redraw -> Redraw

stimes :: Integral b => b -> Redraw -> Redraw

Monoid Redraw

Defined in Vgrep.Event

Methods

mempty :: Redraw

mappend :: Redraw -> Redraw -> Redraw

mconcat :: [Redraw] -> Redraw

data Interrupt

Constructors

Suspend (forall m. MonadIO m => Environment -> m ())

Suspend the application and run the action, e. g. invoking an external process, then resume the application.

Halt

Shut down.

Dispatching Events

dispatch :: (e -> Maybe a) -> e -> Next a

If the lookup returns Just action, then handle it with Continue action', otherwise Skip this event handler.

dispatchMap :: Ord e => Map e a -> e -> Next a

Special case of dispatch where actions are looked up from a map.

Re-exports

data Map k a

A Map from keys k to values a.

The Semigroup operation for Map is union, which prefers values from the left operand. If m1 maps a key k to a value a1, and m2 maps the same key to a different value a2, then their union m1 <> m2 maps k to a1.

Instances

Eq2 Map

Since: containers-0.5.9

Defined in Data.Map.Internal

Methods

liftEq2 :: (a -> b -> Bool) -> (c -> d -> Bool) -> Map a c -> Map b d -> Bool

Ord2 Map

Since: containers-0.5.9

Defined in Data.Map.Internal

Methods

liftCompare2 :: (a -> b -> Ordering) -> (c -> d -> Ordering) -> Map a c -> Map b d -> Ordering

Show2 Map

Since: containers-0.5.9

Defined in Data.Map.Internal

Methods

liftShowsPrec2 :: (Int -> a -> ShowS) -> ([a] -> ShowS) -> (Int -> b -> ShowS) -> ([b] -> ShowS) -> Int -> Map a b -> ShowS

liftShowList2 :: (Int -> a -> ShowS) -> ([a] -> ShowS) -> (Int -> b -> ShowS) -> ([b] -> ShowS) -> [Map a b] -> ShowS

Functor (Map k)

Defined in Data.Map.Internal

Methods

fmap :: (a -> b) -> Map k a -> Map k b

(<$) :: a -> Map k b -> Map k a

Foldable (Map k)

Folds in order of increasing key.

Defined in Data.Map.Internal

Methods

fold :: Monoid m => Map k m -> m

foldMap :: Monoid m => (a -> m) -> Map k a -> m

foldMap' :: Monoid m => (a -> m) -> Map k a -> m

foldr :: (a -> b -> b) -> b -> Map k a -> b

foldr' :: (a -> b -> b) -> b -> Map k a -> b

foldl :: (b -> a -> b) -> b -> Map k a -> b

foldl' :: (b -> a -> b) -> b -> Map k a -> b

foldr1 :: (a -> a -> a) -> Map k a -> a

foldl1 :: (a -> a -> a) -> Map k a -> a

toList :: Map k a -> [a]

null :: Map k a -> Bool

length :: Map k a -> Int

elem :: Eq a => a -> Map k a -> Bool

maximum :: Ord a => Map k a -> a

minimum :: Ord a => Map k a -> a

sum :: Num a => Map k a -> a

product :: Num a => Map k a -> a

Traversable (Map k)

Traverses in order of increasing key.

Defined in Data.Map.Internal

Methods

traverse :: Applicative f => (a -> f b) -> Map k a -> f (Map k b)

sequenceA :: Applicative f => Map k (f a) -> f (Map k a)

mapM :: Monad m => (a -> m b) -> Map k a -> m (Map k b)

sequence :: Monad m => Map k (m a) -> m (Map k a)

(FromJSONKey k, Ord k) => FromJSON1 (Map k)

Defined in Data.Aeson.Types.FromJSON

Methods

liftParseJSON :: (Value -> Parser a) -> (Value -> Parser [a]) -> Value -> Parser (Map k a)

liftParseJSONList :: (Value -> Parser a) -> (Value -> Parser [a]) -> Value -> Parser [Map k a]

Eq k => Eq1 (Map k)

Since: containers-0.5.9

Defined in Data.Map.Internal

Methods

liftEq :: (a -> b -> Bool) -> Map k a -> Map k b -> Bool

Ord k => Ord1 (Map k)

Since: containers-0.5.9

Defined in Data.Map.Internal

Methods

liftCompare :: (a -> b -> Ordering) -> Map k a -> Map k b -> Ordering

(Ord k, Read k) => Read1 (Map k)

Since: containers-0.5.9

Defined in Data.Map.Internal

Methods

liftReadsPrec :: (Int -> ReadS a) -> ReadS [a] -> Int -> ReadS (Map k a)

liftReadList :: (Int -> ReadS a) -> ReadS [a] -> ReadS [Map k a]

liftReadPrec :: ReadPrec a -> ReadPrec [a] -> ReadPrec (Map k a)

liftReadListPrec :: ReadPrec a -> ReadPrec [a] -> ReadPrec [Map k a]

Show k => Show1 (Map k)

Since: containers-0.5.9

Defined in Data.Map.Internal

Methods

liftShowsPrec :: (Int -> a -> ShowS) -> ([a] -> ShowS) -> Int -> Map k a -> ShowS

liftShowList :: (Int -> a -> ShowS) -> ([a] -> ShowS) -> [Map k a] -> ShowS

Ord k => IsList (Map k v)

Since: containers-0.5.6.2

Defined in Data.Map.Internal

Associated Types

type Item (Map k v)

Methods

fromList :: [Item (Map k v)] -> Map k v

fromListN :: Int -> [Item (Map k v)] -> Map k v

toList :: Map k v -> [Item (Map k v)]

(Eq k, Eq a) => Eq (Map k a)

Defined in Data.Map.Internal

Methods

(==) :: Map k a -> Map k a -> Bool

(/=) :: Map k a -> Map k a -> Bool

(Data k, Data a, Ord k) => Data (Map k a)

Defined in Data.Map.Internal

Methods

gfoldl :: (forall d b. Data d => c (d -> b) -> d -> c b) -> (forall g. g -> c g) -> Map k a -> c (Map k a)

gunfold :: (forall b r. Data b => c (b -> r) -> c r) -> (forall r. r -> c r) -> Constr -> c (Map k a)

toConstr :: Map k a -> Constr

dataTypeOf :: Map k a -> DataType

dataCast1 :: Typeable t => (forall d. Data d => c (t d)) -> Maybe (c (Map k a))

dataCast2 :: Typeable t => (forall d e. (Data d, Data e) => c (t d e)) -> Maybe (c (Map k a))

gmapT :: (forall b. Data b => b -> b) -> Map k a -> Map k a

gmapQl :: (r -> r' -> r) -> r -> (forall d. Data d => d -> r') -> Map k a -> r

gmapQr :: forall r r'. (r' -> r -> r) -> r -> (forall d. Data d => d -> r') -> Map k a -> r

gmapQ :: (forall d. Data d => d -> u) -> Map k a -> [u]

gmapQi :: Int -> (forall d. Data d => d -> u) -> Map k a -> u

gmapM :: Monad m => (forall d. Data d => d -> m d) -> Map k a -> m (Map k a)

gmapMp :: MonadPlus m => (forall d. Data d => d -> m d) -> Map k a -> m (Map k a)

gmapMo :: MonadPlus m => (forall d. Data d => d -> m d) -> Map k a -> m (Map k a)

(Ord k, Ord v) => Ord (Map k v)

Defined in Data.Map.Internal

Methods

compare :: Map k v -> Map k v -> Ordering

(<) :: Map k v -> Map k v -> Bool

(<=) :: Map k v -> Map k v -> Bool

(>) :: Map k v -> Map k v -> Bool

(>=) :: Map k v -> Map k v -> Bool

max :: Map k v -> Map k v -> Map k v

min :: Map k v -> Map k v -> Map k v

(Ord k, Read k, Read e) => Read (Map k e)

Defined in Data.Map.Internal

Methods

readsPrec :: Int -> ReadS (Map k e)

readList :: ReadS [Map k e]

readPrec :: ReadPrec (Map k e)

readListPrec :: ReadPrec [Map k e]

(Show k, Show a) => Show (Map k a)

Defined in Data.Map.Internal

Methods

showsPrec :: Int -> Map k a -> ShowS

show :: Map k a -> String

showList :: [Map k a] -> ShowS

Ord k => Semigroup (Map k v)

Defined in Data.Map.Internal

Methods

(<>) :: Map k v -> Map k v -> Map k v

sconcat :: NonEmpty (Map k v) -> Map k v

stimes :: Integral b => b -> Map k v -> Map k v

Ord k => Monoid (Map k v)

Defined in Data.Map.Internal

Methods

mempty :: Map k v

mappend :: Map k v -> Map k v -> Map k v

mconcat :: [Map k v] -> Map k v

(FromJSONKey k, Ord k, FromJSON v) => FromJSON (Map k v)

Defined in Data.Aeson.Types.FromJSON

Methods

parseJSON :: Value -> Parser (Map k v)

parseJSONList :: Value -> Parser [Map k v]

(NFData k, NFData a) => NFData (Map k a)

Defined in Data.Map.Internal

Methods

rnf :: Map k a -> ()

type Item (Map k v)

Defined in Data.Map.Internal

type Item (Map k v) = (k, v)

type Index (Map k a)

Defined in Lens.Micro.GHC

type Index (Map k a) = k

type IxValue (Map k a)

Defined in Lens.Micro.GHC

type IxValue (Map k a) = a

fromList :: Ord k => [(k, a)] -> Map k a

O(n*log n). Build a map from a list of key/value pairs. See also fromAscList. If the list contains more than one value for the same key, the last value for the key is retained.

If the keys of the list are ordered, linear-time implementation is used, with the performance equal to fromDistinctAscList.

fromList [] == empty
fromList [(5,"a"), (3,"b"), (5, "c")] == fromList [(5,"c"), (3,"b")]
fromList [(5,"c"), (3,"b"), (5, "a")] == fromList [(5,"a"), (3,"b")]