insertLookupWithKey -package:ghc-lib-parser

The expression (insertLookupWithKey f k x map) is a pair where the first element is equal to (lookup k map) and the second element equal to (insertWithKey f k x map).

let f key new_value old_value = (show key) ++ ":" ++ new_value ++ "|" ++ old_value
insertLookupWithKey f 5 "xxx" (fromList [(5,"a"), (3,"b")]) == (Just "a", fromList [(3, "b"), (5, "5:xxx|a")])
insertLookupWithKey f 7 "xxx" (fromList [(5,"a"), (3,"b")]) == (Nothing,  fromList [(3, "b"), (5, "a"), (7, "xxx")])
insertLookupWithKey f 5 "xxx" empty                         == (Nothing,  singleton 5 "xxx")

This is how to define insertLookup using insertLookupWithKey:

let insertLookup kx x t = insertLookupWithKey (\_ a _ -> a) kx x t
insertLookup 5 "x" (fromList [(5,"a"), (3,"b")]) == (Just "a", fromList [(3, "b"), (5, "x")])
insertLookup 7 "x" (fromList [(5,"a"), (3,"b")]) == (Nothing,  fromList [(3, "b"), (5, "a"), (7, "x")])

Also see the performance note on fromListWith.

Combines insert operation with old value retrieval. The expression (insertLookupWithKey f k x map) is a pair where the first element is equal to (lookup k map) and the second element equal to (insertWithKey f k x map).

let f key new_value old_value = (show key) ++ ":" ++ new_value ++ "|" ++ old_value
insertLookupWithKey f 5 "xxx" (fromList [(5,"a"), (3,"b")]) == (Just "a", fromList [(3, "b"), (5, "5:xxx|a")])
insertLookupWithKey f 7 "xxx" (fromList [(5,"a"), (3,"b")]) == (Nothing,  fromList [(3, "b"), (5, "a"), (7, "xxx")])
insertLookupWithKey f 5 "xxx" empty                         == (Nothing,  singleton 5 "xxx")

This is how to define insertLookup using insertLookupWithKey:

let insertLookup kx x t = insertLookupWithKey (\_ a _ -> a) kx x t
insertLookup 5 "x" (fromList [(5,"a"), (3,"b")]) == (Just "a", fromList [(3, "b"), (5, "x")])
insertLookup 7 "x" (fromList [(5,"a"), (3,"b")]) == (Nothing,  fromList [(3, "b"), (5, "a"), (7, "x")])

Also see the performance note on fromListWith.

The expression (insertLookupWithKey f k x map) is a pair where the first element is equal to (lookup k map) and the second element equal to (insertWithKey f k x map).

let f key new_value old_value = (show key) ++ ":" ++ new_value ++ "|" ++ old_value
insertLookupWithKey f 5 "xxx" (fromList [(5,"a"), (3,"b")]) == (Just "a", fromList [(3, "b"), (5, "5:xxx|a")])
insertLookupWithKey f 7 "xxx" (fromList [(5,"a"), (3,"b")]) == (Nothing,  fromList [(3, "b"), (5, "a"), (7, "xxx")])
insertLookupWithKey f 5 "xxx" empty                         == (Nothing,  singleton 5 "xxx")

This is how to define insertLookup using insertLookupWithKey:

let insertLookup kx x t = insertLookupWithKey (\_ a _ -> a) kx x t
insertLookup 5 "x" (fromList [(5,"a"), (3,"b")]) == (Just "a", fromList [(3, "b"), (5, "x")])
insertLookup 7 "x" (fromList [(5,"a"), (3,"b")]) == (Nothing,  fromList [(3, "b"), (5, "a"), (7, "x")])

Insert a key-value pair into a map, return the previous key's value if it existed. Inserts the value directly if the key does not exist in the map. Otherwise, apply a supplied function that accepts the key, the new value, and the previous value and insert that result into the map.

O(log n). Combines insert operation with old value retrieval. The expression (insertLookupWithKey f k x map) is a pair where the first element is equal to (lookup k map) and the second element equal to (insertWithKey f k x map).

Inserts a binding into the map. If a binding for the key already exists, then the value obtained by applying the function to the key, the new value and the old value is inserted, and the old value is returned. Precondition: See insertLookupWithKeyPrecondition.

The expression (insertLookupWithKey f k x map) is a pair where the first element is equal to (lookup k map) and the second element equal to (insertWithKey f k x map).

O(log n). Combines insert operation with old value retrieval. The expression (insertLookupWithKey f k x map) is a pair where the first element is equal to (lookup k map) and the second element equal to (insertWithKey f k x map).

let f key new_value old_value = (show key) ++ ":" ++ new_value ++ "|" ++ old_value
insertLookupWithKey f 5 "xxx" (fromList ((5,"a") :| [(3,"b")])) == (Just "a", fromList ((3, "b") :| [(5, "5:xxx|a")]))
insertLookupWithKey f 7 "xxx" (fromList ((5,"a") :| [(3,"b")])) == (Nothing,  fromList ((3, "b") :| [(5, "a"), (7, "xxx")]))

This is how to define insertLookup using insertLookupWithKey:

let insertLookup kx x t = insertLookupWithKey (\_ a _ -> a) kx x t
insertLookup 5 "x" (fromList ((5,"a") :| [(3,"b")])) == (Just "a", fromList ((3, "b") :| [(5, "x")]))
insertLookup 7 "x" (fromList ((5,"a") :| [(3,"b")])) == (Nothing,  fromList ((3, "b") :| [(5, "a"), (7, "x")]))

O(log n). Combines insert operation with old value retrieval. The expression (insertLookupWithKey f k x map) is a pair where the first element is equal to (lookup k map) and the second element equal to (insertWithKey f k x map).

let f key new_value old_value = (show key) ++ ":" ++ new_value ++ "|" ++ old_value
insertLookupWithKey f 5 "xxx" (fromList ((5,"a") :| [(3,"b")])) == (Just "a", fromList ((3, "b") :| [(5, "5:xxx|a")]))
insertLookupWithKey f 7 "xxx" (fromList ((5,"a") :| [(3,"b")])) == (Nothing,  fromList ((3, "b") :| [(5, "a"), (7, "xxx")]))

This is how to define insertLookup using insertLookupWithKey:

let insertLookup kx x t = insertLookupWithKey (\_ a _ -> a) kx x t
insertLookup 5 "x" (fromList ((5,"a") :| [(3,"b")])) == (Just "a", fromList ((3, "b") :| [(5, "x")]))
insertLookup 7 "x" (fromList ((5,"a") :| [(3,"b")])) == (Nothing,  fromList ((3, "b") :| [(5, "a"), (7, "x")]))

O(log n). Combine insert with old values retrieval.

Insert a key-value pair into the map using a combining function, and if the key was already present, the old value is returned along with the proof that the key was present.

Insert a key-value pair into the map using a combining function, and if the key was already present, the old value is returned along with the proof that the key was present.

Insert a key-value pair into the map using a combining function, and if the key was already present, the old value is returned along with the proof that the key was present.

O(log n). A strict version of insertLookupWithKey.

The precondition for insertLookupWithKey f k v m is that, if the value v' is inserted into m, and tag v' is defined, then no key other than k may map to a value v'' for which tag v'' = tag v'.

Deprecated. As of version 0.3, replaced by insertLookupWithKey. O(log n). A strict version of insertLookupWithKey.