Represents a one-to-one mapping between values. So a OneToOne String Int is a one-to-one mapping that lets you look up a String and find the associated Int and vice versa.

Create an empty one-to-one mapping.

empty --> fromList []

Insert a pair of values into a one-to-one mapping. Removes overlapping pairs when there is a collision.

oneToOne : OneToOne Int Int
oneToOne =
    empty
        |> insert 1 1
        |> insert 2 1


oneToOne --> fromList [ ( 2, 1 ) ]

Remove a pair from a one-to-one mapping by the first value. If the pair is not found, no changes are made.

animalNamesToNumbers : OneToOne String Int
animalNamesToNumbers =
    fromList [ ( "Tom", 1 ), ( "Jerry", 2 ) ]


removeFirst "Tom" animalNamesToNumbers --> fromList [ ( "Jerry", 2 ) ]


removeFirst "Quacker" animalNamesToNumbers --> fromList [ ( "Tom", 1 ), ( "Jerry", 2 ) ]

Remove a pair from a one-to-one mapping by the second value. If the pair is not found, no changes are made.

animalNamesToNumbers : OneToOne String Int
animalNamesToNumbers =
    fromList [ ( "Tom", 1 ), ( "Jerry", 2 ) ]


removeSecond 1 animalNamesToNumbers --> fromList [ ( "Jerry", 2 ) ]


removeSecond 3 animalNamesToNumbers --> fromList [ ( "Tom", 1 ), ( "Jerry", 2 ) ]

Determine if a one-to-one mapping is empty.

isEmpty empty --> True


isEmpty (singleton 1 1) --> False

Determine if a first value is in a one-to-one mapping.

memberFirst 1 (singleton 1 2) --> True


memberFirst 2 (singleton 1 2) --> False

Determine if a second value is in a one-to-one mapping.

memberSecond 2 (singleton 1 2) --> True


memberSecond 1 (singleton 1 2) --> False

Extract the first value associated with a second value. If the second value is not found, return Nothing.

animalNamesToNumbers : OneToOne String Int
animalNamesToNumbers =
    fromList [ ( "Tom", 1 ), ( "Jerry", 2 ) ]


first 1 animalNamesToNumbers --> Just "Tom"
first 2 animalNamesToNumbers --> Just "Jerry"
first 3 animalNamesToNumbers --> Nothing

Extract the second value associated with a first value. If the first value is not found, return Nothing.

animalNamesToNumbers : OneToOne String Int
animalNamesToNumbers =
    fromList [ ( "Tom", 1 ), ( "Jerry", 2 ) ]


second "Tom" animalNamesToNumbers --> Just 1
second "Jerry" animalNamesToNumbers --> Just 2
second "Quacker" animalNamesToNumbers --> Nothing

Determine the number of pairs in a one-to-one mapping.

animalNamesToNumbers : OneToOne String Int
animalNamesToNumbers =
   fromList [ ( "Tom", 1 ), ( "Jerry", 2 ) ]


size animalNamesToNumbers --> 2

Convert a one-to-one mapping into an association list of pairs, sorted by the first value.

toList (singleton "tomato" "cabbage") --> [ ( "tomato", "cabbage" ) ]

Convert an association list into a one-to-one mapping.

fromList [ ( "tomato", "cabbage" ) ] --> (singleton "tomato" "cabbage")