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@ -1,39 +1,54 @@
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module Internal.Tools.Hashdict exposing (Hashdict, decoder, empty, encode, fromList, get, insert, isEmpty, keys, member, memberKey, rehash, remove, removeKey, singleton, size, softDecoder, toList, union, values)
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module Internal.Tools.Hashdict exposing
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( Hashdict
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, empty, singleton, insert, remove, removeKey
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, isEmpty, member, memberKey, get, size
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, keys, values, toList, fromList
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, rehash, union
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, encode, decoder, softDecoder
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)
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{-| This module abstracts the `Dict` type with one function that assigns a
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unique identifier for each value based on a function that assigns each value.
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This allows you to store values based on an externally defined identifier.
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## Dictionaries
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@docs Hashdict
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## Build
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@docs empty, singleton, insert, remove, removeKey
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## Query
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@docs isEmpty, member, memberKey, get, size
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## Lists
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@docs keys, values, toList, fromList
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## Transform
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@docs rehash, union
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## JSON coders
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@docs encode, decoder, softDecoder
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-}
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import FastDict as Dict exposing (Dict)
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import Json.Decode as D
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import Json.Encode as E
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{-| A dictionary of keys and values where each key is defined by its value. For
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example, this can be useful when every user is identifiable by their username:
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@ -53,9 +68,11 @@ example, this can be useful when every user is identifiable by their username:
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, height : Float
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}
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In the example listed above, the users are stored by their username, which means
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that all you need to know is the value "Alice" to retrieve all the information
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about them. Additionally, you do not need to specify a key to insert the values.
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-}
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type Hashdict a
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= Hashdict
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@ -63,6 +80,7 @@ type Hashdict a
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, values : Dict String a
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}
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{-| Decode a hashdict from a JSON value. To create a hashdict, you are expected
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to insert a hash function. If the hash function doesn't properly hash the values
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as expected, the decoder will fail to decode the hashdict.
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@ -72,22 +90,25 @@ decoder f xDecoder =
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D.keyValuePairs xDecoder
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|> D.andThen
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(\items ->
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if List.all (\(hash, value) -> f value == hash) items then
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if List.all (\( hash, value ) -> f value == hash) items then
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items
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|> Dict.fromList
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|> (\d -> { hash = f, values = d })
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|> Hashdict
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|> D.succeed
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else
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D.fail "Hash function fails to properly hash all values"
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)
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{-| Create an empty hashdict.
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-}
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empty : (a -> String) -> Hashdict a
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empty hash =
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Hashdict { hash = hash, values = Dict.empty }
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{-| Encode a Hashdict into a JSON value. Keep in mind that an Elm function
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cannot be universally converted to JSON, so it is up to you to preserve that
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hash function!
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@ -99,6 +120,7 @@ encode encodeX (Hashdict h) =
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|> List.map (Tuple.mapSecond encodeX)
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|> E.object
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{-| Convert an association list into a hashdict.
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-}
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fromList : (a -> String) -> List a -> Hashdict a
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@ -111,6 +133,7 @@ fromList hash xs =
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|> Dict.fromList
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}
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{-| Get the value associated with a hash. If the hash is not found, return
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`Nothing`. This is useful when you are not sure if a hash will be in the
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hashdict.
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@ -119,6 +142,7 @@ get : String -> Hashdict a -> Maybe a
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get k (Hashdict h) =
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Dict.get k h.values
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{-| Insert a value into a hashdict. The key is automatically generated by the
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hash function. If the function generates a collision, it replaces the existing
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value in the hashdict.
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@ -127,30 +151,35 @@ insert : a -> Hashdict a -> Hashdict a
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insert v (Hashdict h) =
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Hashdict { h | values = Dict.insert (h.hash v) v h.values }
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{-| Determine if a hashdict is empty.
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-}
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isEmpty : Hashdict a -> Bool
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isEmpty (Hashdict h) =
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Dict.isEmpty h.values
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{-| Get all of the hashes in a hashdict, sorted from lowest to highest.
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-}
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keys : Hashdict a -> List String
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keys (Hashdict h) =
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Dict.keys h.values
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{-| Determine if a value's hash is in a hashdict.
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-}
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member : a -> Hashdict a -> Bool
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member value (Hashdict h) =
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Dict.member (h.hash value) h.values
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{-| Determine if a hash is in a hashdict.
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-}
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memberKey : String -> Hashdict a -> Bool
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memberKey key (Hashdict h) =
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Dict.member key h.values
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{-| Remap a hashdict using a new hashing algorithm.
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-}
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rehash : (a -> String) -> Hashdict a -> Hashdict a
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@ -164,35 +193,42 @@ rehash f (Hashdict h) =
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|> Dict.fromList
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}
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{-| Remove a value from a hashdict. If the value's hash is found, the key-value
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pair is removed. If the value's hash is not found, no changes are made.
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hdict |> Hashdict.remove (User "Alice" 19 1.82)
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-}
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remove : a -> Hashdict a -> Hashdict a
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remove v (Hashdict h) =
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Hashdict { h | values = Dict.remove (h.hash v) h.values }
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{-| Remove a key from a hashdict. If the key is not found, no changes are made.
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hdict |> Hashdict.removeKey "Alice"
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-}
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removeKey : String -> Hashdict a -> Hashdict a
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removeKey k (Hashdict h) =
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Hashdict { h | values = Dict.remove k h.values }
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{-| Create a hashdict with a single key-value pair.
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-}
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singleton : (a -> String) -> a -> Hashdict a
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singleton f v =
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empty f |> insert v
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{-| Determine the number of values in a hashdict.
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-}
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size : Hashdict a -> Int
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size (Hashdict h) =
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Dict.size h.values
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{-| Decode a hashdict from a JSON value. If you cannot deduce the originally
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used hash function, (or if you simply do not care) you can use this function to
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decode and rehash the Hashdict using your new hash function.
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@ -202,13 +238,15 @@ softDecoder f xDecoder =
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D.keyValuePairs xDecoder
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|> D.map (List.map Tuple.second >> fromList f)
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{-| Convert a hashdict into an association list of key-value pairs, sorted by
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keys.
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-}
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toList : Hashdict a -> List (String, a)
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toList : Hashdict a -> List ( String, a )
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toList (Hashdict h) =
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Dict.toList h.values
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{-| Combine two hashdicts under the hash function of the first. If there is a
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collision, preference is given to the first hashdict.
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-}
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@ -221,6 +259,7 @@ union (Hashdict h1) hd2 =
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, values = Dict.union h1.values h2.values
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}
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{-| Get all values stored in the hashdict, in the order of their keys.
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-}
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values : Hashdict a -> List a
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@ -1,4 +1,11 @@
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module Internal.Tools.Iddict exposing (Iddict, decoder, empty, encode, get, insert, isEmpty, keys, map, member, remove, singleton, size, values)
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module Internal.Tools.Iddict exposing
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( Iddict
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, empty, singleton, insert, map, remove
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, isEmpty, member, get, size
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, keys, values
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, encode, decoder
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)
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{-| The id-dict is a data type that lets us store values in a dictionary using
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unique identifiers. This can be used as a dictionary where the keys do not
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matter.
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@ -6,31 +13,38 @@ matter.
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The benefit of the iddict is that it generates the keys FOR you. This way, you
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do not need to generate identifiers yourself.
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## Id-dict
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@docs Iddict
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## Build
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@docs empty, singleton, insert, map, remove
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## Query
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@docs isEmpty, member, get, size
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## Lists
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@docs keys, values
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## JSON coders
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@docs encode, decoder
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-}
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import FastDict as Dict exposing (Dict)
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import Json.Decode as D
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import Json.Encode as E
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{-| The Iddict data type.
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-}
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type Iddict a
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, dict : Dict Int a
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}
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{-| Decode an id-dict from a JSON value.
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-}
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decoder : D.Decoder a -> D.Decoder (Iddict a)
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dict =
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pairs
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|> List.filterMap
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(\(k, v) ->
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(\( k, v ) ->
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k
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|> String.toInt
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|> Maybe.map (\n -> (n, v))
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|> Maybe.map (\n -> ( n, v ))
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)
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|> Dict.fromList
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in
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Iddict
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{ cursor =
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Dict.keys dict -- Larger than all values in the list
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Dict.keys dict
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-- Larger than all values in the list
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|> List.map ((+) 1)
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|> List.maximum
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|> Maybe.withDefault 0
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|> max (Dict.size dict) -- At least the dict size
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|> max c -- At least the given value
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|> max (Dict.size dict)
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-- At least the dict size
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|> max c
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-- At least the given value
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, dict = dict
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}
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)
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(D.field "cursor" D.int)
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(D.field "dict" <| D.keyValuePairs xDecoder)
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{-| Create an empty id-dict.
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-}
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empty : Iddict a
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, dict = Dict.empty
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}
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{-| Encode an id-dict to a JSON value.
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-}
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encode : (a -> E.Value) -> Iddict a -> E.Value
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encode encodeX (Iddict d) =
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E.object
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[ ( "cursor", E.int d.cursor )
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, ( "dict",
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d.dict
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, ( "dict"
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, d.dict
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|> Dict.toCoreDict
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|> E.dict String.fromInt encodeX
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)
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]
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{-| Get a value from the id-dict using its key.
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-}
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get : Int -> Iddict a -> Maybe a
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get k (Iddict { dict }) =
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Dict.get k dict
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{-| Insert a new value into the id-dict. Given that the id-dict generates its
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key, the function returns both the updated id-dict as the newly generated key.
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@ -107,25 +130,29 @@ key, the function returns both the updated id-dict as the newly generated key.
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case x of
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( _, iddict ) ->
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get 0 iddict -- Just "hello"
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-}
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insert : a -> Iddict a -> (Int, Iddict a)
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insert : a -> Iddict a -> ( Int, Iddict a )
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insert v (Iddict d) =
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( d.cursor
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, Iddict { cursor = d.cursor + 1, dict = Dict.insert d.cursor v d.dict }
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)
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{-| Determine if an id-dict is empty.
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-}
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isEmpty : Iddict a -> Bool
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isEmpty (Iddict d) =
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Dict.isEmpty d.dict
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{-| Get all of the keys from the id-dict, sorted from lowest to highest.
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-}
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keys : Iddict a -> List Int
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keys (Iddict { dict }) =
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Dict.keys dict
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{-| Map an existing value at a given key, if it exists. If it does not exist,
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the operation does nothing.
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-}
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map k f (Iddict d) =
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Iddict { d | dict = Dict.update k (Maybe.map f) d.dict }
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{-| Determine if a key is in an id-dict.
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-}
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member : Int -> Iddict a -> Bool
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member k (Iddict d) =
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k < d.cursor && Dict.member k d.dict
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{-| Remove a key-value pair from the id-dict. If the key is not found, no
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changes are made.
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-}
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remove k (Iddict d) =
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Iddict { d | dict = Dict.remove k d.dict }
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{-| Create an id-dict with a single value.
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-}
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singleton : a -> (Int, Iddict a)
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singleton v = insert v empty
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singleton : a -> ( Int, Iddict a )
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singleton v =
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insert v empty
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{-| Determine the number of key-value pairs in the id-dict.
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-}
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size (Iddict d) =
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Dict.size d.dict
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{-| Get all of the values from an id-dict, in the order of their keys.
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-}
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values : Iddict a -> List a
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Reference in New Issue