A map from ByteStrings to a. For all the generic functions, note that tries are strict in the Maybe but not in a.

The Monad instance is strange. If a key k1 is a prefix of other keys, then results from binding the value at k1 will override values from longer keys when they collide. If this is useful for anything, or if there's a more sensible instance, I'd be curious to know.

\(\mathcal{O}(1)\). Construct the empty trie.

\(\mathcal{O}(1)\). Is the trie empty?

\(\mathcal{O}(1)\). Construct a singleton trie.

\(\mathcal{O}(n)\). Get count of elements in trie.

Convert association list into a trie. On key conflict, values earlier in the list shadow later ones.

Convert trie into association list. The list is ordered according to the keys.

Warning: This function suffers Bug #25.

Convert a trie into a list using a function. Resulting values are in key-sorted order.

Warning: This function suffers Bug #25.

Return all values in the trie, in key-sorted order.

Note: Prior to version 0.2.7, this function suffered Bug #25; but it no longer does.

Since: 0.2.2

Generic function to find a value (if it exists) and the subtrie rooted at the prefix. The first function argument is called if and only if a node is exactly reachable by the query; if no node is exactly reachable the default value is used; if the middle of an arc is reached, the second function argument is used.

This function is intended for internal use. For the public-facing version, see lookupBy.

Note: Type changed in 0.2.7

Return the subtrie containing all keys beginning with a prefix.

Given a query, find the longest prefix with an associated value in the trie, returning the length of that prefix and the associated value.

This function may not have the most useful return type. For a version that returns the prefix itself as well as the remaining string, see match.

Since: 0.2.4

Given a query, find all prefixes with associated values in the trie, and return the length of each prefix with their value, in order from shortest prefix to longest. This function is a good producer for list fusion.

This function may not have the most useful return type. For a version that returns the prefix itself as well as the remaining string, see matches.

Since: 0.2.4

Generic function to alter a trie by one element with a function to resolve conflicts (or non-conflicts).

A variant of alterBy which also allows modifying the sub-trie. If the function returns (Just v, t) and lookup empty t == Just w, then the w will be overwritten by v.

Note: Type changed in 0.2.6

Since: 0.2.3

Apply a function to the value at a key. If the key is not present, then the trie is returned unaltered.

Take the union of two tries, using a function to resolve conflicts. The resulting trie is constructed strictly, but the results of the combining function are evaluated lazily.

Take the union of two tries, using a function to resolve collisions. This can only define the space of functions between union and symmetric difference but, with those two, all set operations can be defined (albeit inefficiently).

Take the intersection of two tries, using a function to resolve collisions.

Since: 0.2.6

Return the lexicographically smallest ByteString and the value it's mapped to; or Nothing for the empty trie. When one entry is a prefix of another, the prefix will be returned.

Note: Prior to version 0.2.7, this function suffered Bug #25; but it no longer does.

Since: 0.2.2

Return the lexicographically largest ByteString and the value it's mapped to; or Nothing for the empty trie. When one entry is a prefix of another, the longer one will be returned.

Note: Prior to version 0.2.7, this function suffered Bug #25; but it no longer does.

Since: 0.2.2

Update the minAssoc and return the old minAssoc.

Note: Prior to version 0.2.7, this function suffered Bug #25; but it no longer does.

Since: 0.2.2

Update the maxAssoc and return the old maxAssoc.

Note: Prior to version 0.2.7, this function suffered Bug #25; but it no longer does.

Since: 0.2.2

Retain only those values which satisfy some predicate.

Laws

Since: 0.2.7

Apply a function to all values, potentially removing them.

Laws

Keyed version of filterMap.

Warning: This function suffers Bug #25.

An effectful version of filter.

Laws

-- Like 'liftA2' for the @(a->)@ monad, but horizontal.
-- The function definition should (hopefully) be straightforward
-- to follow; however, do beware the oddly criss-crossed types
-- for @g@ and @f@.
underA2 :: (Applicative f, Applicative g)
        => (b -> c -> d)
        -> (a -> g b)
        -> (a -> f c)
        -> a -> Compose f g d
underA2 h g f = liftA2 (liftA2 h) (g `under` pure) (pure `under` f)

Since: 0.2.7

An effectful version of filterMap.

Laws

under :: Functor f
      => (b -> g c)
      -> (a -> f b)
      -> a -> Compose f g c
under g f = Compose . fmap g . f

-- | Variant of wither for Maybe instead of Trie.
wither_Maybe :: Applicative f
             => (a -> f (Maybe b))
             -> Maybe a -> f (Maybe b)
wither_Maybe f = fmap join . traverse f

traverse f `under` traverse g ≡ traverse (f `under` g)

Since: 0.2.7

A variant of fmap which provides access to the subtrie rooted at each value.

Since: 0.2.3

A variant of contextualMap which evaluates the function strictly.

Since: 0.2.3

Contextual variant of filterMap.

Since: 0.2.3

Contextual variant of mapBy, aka keyed variant of contextualFilterMap.

Warning: This function suffers Bug #25.

Since: 0.2.3

Keyed variant of foldr.

Warning: This function suffers Bug #25.

Since: 0.2.2

Keyed variant of foldr'.

Warning: This function suffers Bug #25.

Since: 0.2.7

Keyed variant of foldl.

Warning: This function suffers Bug #25.

Since: 0.2.7

Keyed variant of foldl'.

Warning: This function suffers Bug #25.

Since: 0.2.7

Catamorphism for tries. Unlike most other functions (mapBy, contextualMapBy, foldrWithKey, etc), this function does not reconstruct the full ByteString for each value; instead it only returns the suffix since the previous value or branch point.

This function is a direct/literal catamorphism of the implementation datatype, erasing only some bitmasking metadata for the branches. For a more semantic catamorphism, see cata.

Since: 0.2.6

Catamorphism for tries. Unlike most other functions (mapBy, contextualMapBy, foldrWithKey, etc), this function does not reconstruct the full ByteString for each value; instead it only returns the suffix since the previous value or branch point.

This function is a semantic catamorphism; that is, it tries to express the invariants of the implementation, rather than exposing the literal structure of the implementation. For a more literal catamorphism, see cata_.

Since: 0.2.6

Keyed version of traverse.

Warning: This function suffers Bug #25.

Since: 0.2.7

Visualization fuction for debugging.

Returns the longest shared prefix and the two remaining suffixes for a pair of strings. This function performs no allocation/copying, it simply returns slices/views of the arguments.

• s ≡ (\(pre,s',z') -> pre <> s') (breakMaximalPrefix s z)

• z ≡ (\(pre,s',z') -> pre <> z') (breakMaximalPrefix s z)

Since: 0.2.2