| Copyright | (c) Adam Conner-Sax 2019 |
|---|---|
| License | BSD |
| Maintainer | adam_conner_sax@yahoo.com |
| Stability | experimental |
| Safe Haskell | None |
| Language | Haskell2010 |
Frames.Folds
Contents
Description
Frames.Folds contains various helper functions designed to simplify folding over Frames/Vinyl records given some way of folding over each column.
Synopsis
- type EndoFold a = Fold a a
- newtype FoldEndo t = FoldEndo {
- unFoldEndo :: EndoFold (Snd t)
- newtype FoldRecord f rs a = FoldRecord {
- unFoldRecord :: Fold (Record rs) (f a)
- recFieldF :: forall t rs a. KnownField t => Fold a (Snd t) -> (Record rs -> a) -> FoldRecord ElField rs t
- sequenceRecFold :: forall as rs. Rec (FoldRecord ElField as) rs -> Fold (Record as) (Record rs)
- sequenceEndoFolds :: forall rs. (RApply rs, RPureConstrained KnownField rs, EndoFieldFoldsToRecordFolds rs) => Rec FoldEndo rs -> Fold (Record rs) (Record rs)
- foldAll :: (RPureConstrained KnownField rs, RApply rs, EndoFieldFoldsToRecordFolds rs) => (forall a. Fold a a) -> Fold (Record rs) (Record rs)
- foldAllConstrained :: forall c rs. (RPureConstrained (ConstrainedField c) rs, RPureConstrained KnownField rs, RApply rs, EndoFieldFoldsToRecordFolds rs) => (forall a. c a => Fold a a) -> Fold (Record rs) (Record rs)
- foldAllMonoid :: forall f rs. (RPureConstrained (ConstrainedField (MonoidalField f)) rs, RPureConstrained KnownField rs, RApply rs, EndoFieldFoldsToRecordFolds rs) => Fold (Record rs) (Record rs)
Types
Types to act as "interpretation functors" for records of folds
Wrapper for Endo-folds of the field types of ElFields
Constructors
| FoldEndo | |
Fields
| |
newtype FoldRecord f rs a Source #
Wrapper for folds from a record to an interpreted field. Usually f ~ ElField
Constructors
| FoldRecord | |
Fields
| |
functions for building records of folds
Arguments
| :: KnownField t | |
| => Fold a (Snd t) | A fold from some type a to the field type of an ElField |
| -> (Record rs -> a) | a function to get the a value from the input record |
| -> FoldRecord ElField rs t | the resulting |
Helper for building a FoldRecord from a given fold and function of the record
functions for turning records of folds into folds of records
sequenceRecFold :: forall as rs. Rec (FoldRecord ElField as) rs -> Fold (Record as) (Record rs) Source #
Turn a Record of folds into a fold over records
sequenceEndoFolds :: forall rs. (RApply rs, RPureConstrained KnownField rs, EndoFieldFoldsToRecordFolds rs) => Rec FoldEndo rs -> Fold (Record rs) (Record rs) Source #
turn a record of endo-folds over each field, into a fold over records
functions using constraints to extend an endo-fold across a record
foldAll :: (RPureConstrained KnownField rs, RApply rs, EndoFieldFoldsToRecordFolds rs) => (forall a. Fold a a) -> Fold (Record rs) (Record rs) Source #
apply an unconstrained endo-fold, e.g., a fold which takes the last item in a container, to every field in a record
foldAllConstrained :: forall c rs. (RPureConstrained (ConstrainedField c) rs, RPureConstrained KnownField rs, RApply rs, EndoFieldFoldsToRecordFolds rs) => (forall a. c a => Fold a a) -> Fold (Record rs) (Record rs) Source #
Apply a constrained endo-fold to all fields of a record. May require a use of TypeApplications, e.g., foldAllConstrained @Num FL.sum
foldAllMonoid :: forall f rs. (RPureConstrained (ConstrainedField (MonoidalField f)) rs, RPureConstrained KnownField rs, RApply rs, EndoFieldFoldsToRecordFolds rs) => Fold (Record rs) (Record rs) Source #
Given a monoid-wrapper, e.g., Sum, apply the derived endo-fold to all fields of a record This is strictly less powerful than foldAllConstrained but might be simpler to use in some cases