name:                references
version:             0.3.0.1
synopsis:            Selectors for reading and updating data.

description:         References are data accessors that can read, write or update the accessed infromation through their context. They are first-class values, can be passed in functions, transformed, combined. References generalize lenses, folds and traversals for haskell (see: < https://hackage.haskell.org/package/lens>).
		     .
             References are more general than field selectors in traditional languages.
             .
              * References are first-class values. If there is a struct in C, for example, with an `int` field `fl`, then fl can only be used as part of an expression. One can not generalize a function to take a field selector and transform the selected data or use it in other ways.
             .
              * They can have different meanings, while field accessors can only represent data-level containment. They can express uncertain containment (like field selectors of C unions), different viewpoints of the same data, and other concepts.
             .              
		     There are two things that references can do but the previously mentioned access methods don't.
		     .
		      * References can cooperate with monads, for example IO. This opens many new applications.
             .
		      * References can be added using the @&+&@ operator, to create new lenses more easily.
		     .
		     Basic idea taken from the currently not maintained package <https://hackage.haskell.org/package/yall>. 
		     .
		     An example use of the references (a logger application that spawns new threads to update a global log):
		     .
		     > logger =
		     >   (forever $ do
		     >      log <- logChan ^? chan&logRecord    -- Extract the log record from the received log message
		     >      thrId <- forkIO (do time <- getTime
		     >                          ioref&lastLogTime != time $ logDB     -- Update the last logging time mutable log database
		     >                          let logMsg = senderThread .- show     -- Transform the thread id to a string and
		     >                                         $ loggingTime .= time  -- update the time
		     >                                         $ log                  -- inside the log message
		     >                          ioref&debugInfos !~ addLogEntry log $ logDB  -- update the table of log entries
		     >                          mvar !- (+1) $ count )
		     >      mvar !- (thrId:) $ updaters                               -- Record the spawned thread
		     >     ) `catch` stopUpdaters updaters
		     >   where stopUpdaters updaters ThreadKilled =    
		     >           mvar&traverse !| killThread $ updaters               -- Kill all spawned threads before stopping
		     .
		     There are a bunch of predefined references for datatypes included in standard libraries.
		     .
		     New references can be created in several ways:
		     .
		      * From getter, setter and updater, using the @reference@ function.
		     .
              * From getter and setter, using one of the simplified functions (@lens@, @simplePartial@, @partial@, ...).
		     .
		      * Using the `Data.Traversal` instance on a datatype to generate a traversal of each element.
		     .
		      * Using lenses from `Control.Lens` package. There are a lot of packages defining lenses, folds and traversals
		        for various data structures, so it is very useful that all of them can simply be converted into a reference.
		     .
		      * Generating references for newly defined datatypes using the `makeReferences` Template Haskell function.
		     .

homepage:            https://github.com/lazac/references
license:             BSD3
license-file:        LICENSE
author:              Boldizsar Nemeth
maintainer:          nboldi@elte.hu
copyright:           Boldizsar Nemeth, 2014
category:            Control
build-type:          Simple
cabal-version:       >=1.8

extra-source-files:
  README.md
  CHANGELOG.md
  Control/Reference/Examples/Examples.hs
  Control/Reference/Examples/Main.hs

test-suite lens-creation
  type:           exitcode-stdio-1.0
  main-is:        Control/Reference/Examples/Main.hs
  build-depends:  base, text, array, mtl, transformers, containers
                , either, template-haskell, instance-control, directory
                , filepath, HUnit, lens
  
source-repository head
  type:       git
  location:   git://github.com/lazac/references.git
                     
library
  exposed-modules:     Control.Reference
                     , Control.Reference.Representation
                     , Control.Reference.Types
                     , Control.Reference.Combinators
                     , Control.Reference.Operators
                     , Control.Reference.Generators
                     , Control.Reference.Predefined
                     , Control.Reference.Predefined.Containers
                     , Control.Reference.Predefined.Containers.Tree
                     , Control.Reference.TupleInstances
                     , Control.Reference.InternalInterface
                     , Control.Reference.TH.Records
                     , Control.Reference.TH.Tuple
                     , Control.Reference.Examples.TH
  build-depends:       base                 >= 4.6 && < 5 
                     , uniplate             >= 1.6 && < 2
                     , text                 >= 1.1 && < 2
                     , array                >= 0.5 && < 1
                     , mtl                  >= 2.2 && < 3
                     , transformers         >= 0.4 && < 1
                     , containers           >= 0.5 && < 1
                     , either               >= 4.3 && < 5
                     , template-haskell     >= 2.8 && < 3
                     , instance-control     >= 0.1 && < 1
                     , directory            >= 1.2 && < 2
                     , filepath             >= 1.3 && < 2