Cabal-Version:       2.4
Name:                mutable-lens
Version:             0.4.1.0
Synopsis:            Interoperate mutable references with regular lens
Description:
  Use mutable references as lens, compose them with other lens, and run them.
  .
  You may have heard of lens being described as "functional" or "first-class"
  references, with some nice properties such as composition. However the
  equivalence is more than just abstract - mutable references can be readily
  converted into lens form, interoperable with other pure lens. This makes use
  of the fact that "mutability" in a high-level language focusing on purity, is
  really just an alias for a pure state monad that is treated specially by the
  runtime system. A mutable reference over a value of type @a@ with world state
  of type @s@, *is* therefore an actual @Lens s s a a@. There is no need for
  handwaving or connotative language, the isomorphism is direct and concrete.
  .
  This package demonstrates this isomorphism, converting between the two forms.
  You then have access to the whole of the lens ecosystem and its compositional
  properties, and use them with mutable references without other special-cased
  shims or mutable-specific abstractions.
  .
  Uniformity of API is another major benefit - if you want to switch to a
  different reference type, you only have to change your type definitions and
  imports, you don't have to change all @readSomeVar@ to @readOtherVar@,
  @writeSomeVar@ to @writeOtherVar@, or was it @putOtherVar@, and does the
  @atomicModifyVar@ function take a @s -> (a, s)@ or a @s -> (s, a)@ again?
  .
  A word of warning: this package has not been optimised for performance, and
  currently only supports GHC. We would certainly welcome contributions in
  these areas, if you are interested in running this code in production. On the
  other hand for what it's worth, our initial benchmarks suggest that the
  performance degradation is not signficant - ~13% with -O2 in a program that
  reads and writes to references and does no other useful work. In a real
  program that does other useful work, this number will be smaller.
  .
  See unit tests for example usage, e.g.
  <https://github.com/infinity0/hs-mutable-lens/tree/master/test/Control/Lens/MutableTest.hs MutableTest>
Homepage:            https://github.com/infinity0/hs-mutable-lens
Bug-Reports:         https://github.com/infinity0/hs-mutable-lens/issues
License:             Apache-2.0
License-File:        LICENSE.Apache-2
Author:              Ximin Luo
Maintainer:          infinity0@pwned.gg
Copyright:           2020 Ximin Luo
category:            Data, Lenses, Generics
Tested-With:         GHC >= 8.10.1
Extra-Source-Files:  CHANGELOG.md

Source-Repository head
  Type: git
  Location: https://github.com/infinity0/hs-mutable-lens

Flag dev
  Description:
    Set compile flags for development.
  Default:     False
  Manual:      True

Flag release
  Description:
    Set compile flags for release-checking. Users don't need this.
  Default:     False
  Manual:      True

Common generic
  Default-Language: Haskell2010
  Build-Depends: base >= 4 && < 5,
  GHC-Options:
    -Wall
    -Wcompat
    -Wno-unused-matches
    -Wredundant-constraints
    -Wincomplete-record-updates
    -Wincomplete-uni-patterns
    -Wunused-packages
  if flag(dev)
    GHC-Options:
      -O2
    -- some optimisations cause memory leaks; switch on -O2 and profiling so we
    -- can detect this during development so it doesn't cause surprises later
    GHC-Prof-Options:
    -- note: adding -fprof-auto gives unfair benchmark results with profiling,
    -- since many more SCCs are added for our code than for GHC native refs.
  if flag(release)
    GHC-Options:
      -Werror

Common executable
  GHC-Options:
    -threaded
  if flag(dev)
    GHC-Options:
      -rtsopts

Library
  Import: generic
  Build-Depends:
      base >=4.12.0.0 && <5
    , lens
    , primitive
    , stm
  HS-Source-Dirs: src
  Exposed-Modules:
      Control.Lens.Mutable
    , Control.Lens.Mutable.Internal
    , Control.Lens.Mutable.Types

Test-Suite doctests
  Import: generic, executable
  Build-Depends:
      doctest
  HS-Source-Dirs: test
  Type: exitcode-stdio-1.0
  Main-Is: DocTests.hs

Test-Suite unit
  Import: generic, executable
  Build-Depends:
      tasty
    , tasty-hunit
    , containers
    , lens
    , mutable-lens
    , primitive
    , stm
    , transformers
  HS-Source-Dirs: test
  Type: exitcode-stdio-1.0
  Main-Is: UnitTests.hs
  Other-Modules:
      Control.Lens.MutableTest

Benchmark basic-benchmark
  Import: generic, executable
  Build-Depends:
      mutable-lens
    , extra >= 1.7
    , primitive
  HS-Source-Dirs: test
  Type: exitcode-stdio-1.0
  Main-Is: BasicBenchmark.hs