labels: Anonymous records via named tuples

Declare and access tuple fields with labels. An approach to anonymous records.

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Versions [RSS]	0.0.0, 0.1.0, 0.1.1, 0.1.2, 0.2.0, 0.3.0, 0.3.1, 0.3.2, 0.3.3
Change log	CHANGELOG
Dependencies	base (>=4.7 && <5), template-haskell [details]
License	BSD-3-Clause
Copyright	2016 Chris Done
Author	Chris Done
Maintainer	chrisdone@gmail.com
Category	Development
Home page	https://github.com/chrisdone/labels#readme
Source repo	head: git clone https://github.com/chrisdone/labels
Uploaded	by ChrisDone at 2017-01-20T11:06:16Z
Distributions	LTSHaskell:0.3.3, NixOS:0.3.3, Stackage:0.3.3
Reverse Dependencies	3 direct, 9 indirect [details]
Downloads	6440 total (50 in the last 30 days)
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Status	Docs available [build log] Last success reported on 2017-01-20 [all 1 reports]

Declare and access tuple fields with labels

This package is experimental, exploring the design space opened up by the implemented and to-be-implemented work on extensible records in GHC.

Note: You need GHC 8.0.1 for the #foo syntax, otherwise you have to use $("foo") which works on GHC 7.10.

Enable these extensions:

In GHCi: :set -XOverloadedLabels -XTypeOperators -XDataKinds -XFlexibleContexts
In a module: {-# LANGUAGE OverloadedLabels, TypeOperators, DataKinds, FlexibleContexts #-}

Let's use GHCi:

> import Labels
> :set -XOverloadedLabels -XTypeOperators -XDataKinds -XFlexibleContexts

Construct a record	> (#foo := "hi", #bar := 123) (#foo := "hi",#bar := 123)
Get fields of a record	> get #bar (#foo := "hi", #bar := 123) 123
Set fields of a record	> set #bar 66 (#foo := "hi", #bar := 123) (#foo := "hi",#bar := 66)
Modify fields of a record	> modify #mu (*0.1) (#bar := "hi", #mu := 123) (#bar := "hi",#mu := 12.3)
Add fields to a record	> cons (#mu := [1,2,3]) (#foo := "hi", #bar := 123) (#mu := [1,2,3],#foo := "hi",#bar := 123)
Abstraction	> let double field record = set field (get field record * 2) record > double #mu (#bar := "hi", #mu := 123) (#bar := "hi",#mu := 246)