Editing CTRex (section)

= Introduction =

This page describes the design, usage and motivation for [https://github.com/atzeus/CTRex CTRex].

CTRex is a library for Haskell which implements extensible records using closed type families, datakinds and type literals. It does '''not''' use overlapping instances.

Features:

* Row-polymorphism

* Support for scoped labels (i.e. duplicate labels) '''and''' non-scoped labels (i.e. the lacks predicate on rows).

* The value level interface and the type level interface correspond to each other. 

* The order of labels (except for duplicate labels) does not matter. I.e. {x = 0, y = 0} and {y = 0, x = 0} have the '''same type'''.

* Syntactic sugar on the value level as well as type level.

* If all values in a record satisfy a constraint such as <hask>Show</hask>, then we are able to do operations on all fields in a record, if that operation only requires that the constraint is satisfied. In this way we can create instances such as <hask> Forall r Show => Show (Rec r) </hask>. This is available to the application programmer as well.

* Fast extend, lookup and restriction (all O(log n)) using HashMaps.

The haddock documentation is available [http://homepages.cwi.nl/~ploeg/openrecdocs/Records.html here].