has: Generic Haskell's Record Accessors

Versions [RSS]	0.1, 0.2, 0.2.1, 0.3, 0.4, 0.4.0.1, 0.5.0.0, 0.5.0.1, 0.6.0.1
Dependencies	base (>=4 && <5), HUnit, test-framework, test-framework-hunit [details]
License	BSD-3-Clause
Copyright	(c) Yusaku Hashimoto 2010
Author	Yusaku Hashimoto
Maintainer	Yusaku Hashimoto <nonowarn@gmail.com>
Category	Data
Home page	http://github.com/nonowarn/has
Source repo	head: git clone git://github.com/nonowarn/has.git
Uploaded	by YusakuHashimoto at 2010-03-03T00:46:11Z
Distributions
Reverse Dependencies	2 direct, 0 indirect [details]
Executables	test
Downloads	7068 total (22 in the last 30 days)
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Status	Docs uploaded by user Build status unknown [no reports yet]

Readme for has-0.2

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has

This is a library which provides generic accessors for records.

-- This example is based on fclabel's one: http://hackage.haskell.org/package/fclabels

import Data.Has

import Control.Arrow

type Person = Name :*: Age :*: Sex :*: Place
type Place  = City :*: Country

newtype Name = Name { unName :: String }
newtype Age  = Age  { unAge  :: Int    }
data    Sex  = Male | Female
newtype City = City { unCity :: String }
newtype Country = Country { unCountry :: String }

nonowarn :: Person
nonowarn =   Name "nonowarn"
         :*: Age 17
         :*: Male
         :*: City "Yokohama"
         :*: Country "Japan"

getAge :: (Has Age a) => a -> Int
getAge = unAge . prj

moveToKyoto :: (Has City a) => a -> a
moveToKyoto = inj (City "Kyoto")

getCity :: (Has City a) => a -> String
getCity = unCity . prj

spendFourYears :: (Has Age a) => a -> a
spendFourYears = upd (Age . (+4) . unAge)

test = (21,"Kyoto") == ((getAge &&& getCity) . spendFourYears . moveToKyoto $ nonowarn)