Safe Haskell	None
Language	Haskell2010

Servant.Util.Dummy.Sorting

Description

Implements plain lexicographical sorting.

Example:

sortingSpecApp
    :: MyObject
    -> SortingSpecApp
        DummySortingBackend
        [ "id" ?: Int
        , "desc" ?: Text
        ]
sortingSpecApp obj =
    fieldSort "id" (id obj) .*.
    fieldSort "desc" (desc obj) .*.
    HNil

Next, you use sortBySpec to apply sorting.

sortObjects sorting = filter (sortBySpec sorting . sortingSpecApp) allObjects

Synopsis

type SortingSpecApp backend (allParams :: [TyNamedParam *]) = HList (SortingApp backend) allParams
fieldSort :: forall name a backend. (SortingBackend backend, SortedValueConstraint backend a) => SortedValue backend a -> SortingApp backend ('TyNamedParam name a)
sortBySpec :: (backend ~ DummySortingBackend, allParams ~ AllSortingParams provided base, ApplyToSortItem backend allParams) => SortingSpec provided base -> (a -> SortingSpecApp backend allParams) -> [a] -> [a]

Documentation

type SortingSpecApp backend (allParams :: [TyNamedParam *]) = HList (SortingApp backend) allParams Source #

List of SortingApp functions. Describes how to apply SortingSpec params (each of possible SortingItem) to an SQL query.

Instance of this type can be created using fieldSort function. For example:

sortingSpecApp :: SortingSpecApp ["course" ?: Course, "desc" ?: Text]
sortingSpecApp =
    fieldSort "course" courseField .*.
    fieldSort "desc" descField .*.
    HNil

Annotating fieldSort call with parameter name is not mandatory but recommended to prevent possible mistakes in fieldSorts ordering.

fieldSort :: forall name a backend. (SortingBackend backend, SortedValueConstraint backend a) => SortedValue backend a -> SortingApp backend ('TyNamedParam name a) Source #

sortBySpec :: (backend ~ DummySortingBackend, allParams ~ AllSortingParams provided base, ApplyToSortItem backend allParams) => SortingSpec provided base -> (a -> SortingSpecApp backend allParams) -> [a] -> [a] Source #

Applies a whole filtering specification to a set of response fields. Resulting value can be put to filter function.