122 lines
3.3 KiB
Markdown
122 lines
3.3 KiB
Markdown
Protolude
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=========
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[](https://travis-ci.org/sdiehl/protolude)
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[](https://hackage.haskell.org/package/protolude)
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A sensible starting Prelude for building custom Preludes.
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Design points:
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* Banishes String.
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* Banishes partial functions.
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* Compiler warning on bottoms.
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* Polymorphic string IO functions.
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* Polymorphic show.
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* Automatic string conversions.
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* Types for common data structures in scope.
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* Types for all common string types in scope.
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* Banishes impure exception throwing outside of IO.
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* StateT/ReaderT/ExceptT transformers in scope by default.
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* Foldable / Traversable functions in scope by default.
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* Unsafe functions are prefixed with "unsafe" in separate module.
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* Compiler agnostic, GHC internal modules are abstracted out into Base.
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* Compatibility with GHC 8.0.
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* Includes Semiring for GHC >= 7.6.
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* Includes Bifunctor for GHC >= 7.6.
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* Includes Semigroup for GHC >= 7.6.
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Supports:
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* GHC 7.6.1
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* GHC 7.6.2
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* GHC 7.6.3
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* GHC 7.8.1
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* GHC 7.8.2
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* GHC 7.8.3
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* GHC 7.8.4
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* GHC 7.10.1
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* GHC 7.10.2
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* GHC 7.10.3
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* GHC 8.0.1
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* GHC HEAD
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Usage
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-----
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In your project simply disable the default Prelude and import Protolude.
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```haskell
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{-# LANGUAGE NoImplicitPrelude #-}
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import Protolude
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```
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To try out standalone prelude at the interactive shell, from the Protolude
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project directory run.
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```haskell
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$ stack exec ghci
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> import Protolude
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```
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Dependencies
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------------
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Protolude tries to be light on dependencies and only pulls in *essential*
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libraries that are universally common across most real-world projects. Lower and
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upper bounds are fully specified and compatible with both vanilla Cabal and
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tracks Stack LTS resolver.
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| Dependencies | Lower | Upper |
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| ----------- | -------- | -------- |
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| array | | 0.5 |
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| async | 2.1 | 2.2 |
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| base | 4.6 | 4.10 |
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| binary | | 0.7 |
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| bytestring | 0.10 | 0.11 |
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| containers | 0.5 | 0.6 |
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| deepseq | 1.3 | 1.5 |
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| ghc-prim | 0.3 | 0.6 |
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| integer-gmp | 1.0 | 1.0 |
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| mtl | 2.1 | 2.3 |
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| safe | 0.3 | 0.4 |
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| stm | 2.4 | 2.5 |
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| text | 1.2 | 1.3 |
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| transformers | 0.4 | 0.6 |
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FAQs
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----
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* My ``putStrLn`` and ``putStr`` instances are no longer inferred in the presense
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of the ``-XOverloadedStrings`` extension?
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Because the print functions are polymorphic the type of the print functions may
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require annotations if the type is not fully specified by inference. To force a
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specific type at the call site use either
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```haskell
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putText :: MonadIO m => T.Text -> m ()
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putLText :: MonadIO m => TL.Text -> m ()
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```
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* How do I write manual Show instances if ``show`` isn't provided?
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Generally speaking writing manual instances of Show is a [Haskell antipattern](
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http://www.stephendiehl.com/posts/strings.html) because it produces
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law-violating instances of Show. You probably want to use a pretty printer
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library for custom printing.
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If backwards compatibility is needed then the base library can be imported
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manually.
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```haskell
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import GHC.Show (Show(..))
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```
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License
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-------
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Released under the MIT License.
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Copyright (c) 2016, Stephen Diehl
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