Haskell¶

Изучение¶

Денис Москвин. Функциональное программирование на языке Haskell. stepik.org, видеокурс

Часть 1.
Часть 2.

О Haskell по-человечески
Learn You a Haskell for Great Good!
Real World Haskell by Bryan O'Sullivan, Don Stewart, and John Goerzen

ru.haskell— сообщество русскоговорящих Haskell-разработчиков

Полезные ссылки

ru.haskell wiki

Настройка редакторов для поддержки Haskell

Haskell Cheatsheet
haskell-trainings
Stack cookbook
The Haskell Phrasebook

Best practices¶

• Import modules properly
• deriving via

snippets¶

• HaskellMaybeChecks
• HaskellTypeLevelMachine

ghci running¶

stack ghci protesk:lib protesk:exe:example-that-uses-protesk

^^ running an executable that depends on the main lib requires listing the lib on the console!!

ghci debugging¶

:set -fbreak-on-error -fbreak-on-exception
:trace machineMain
:force _exception
:hist
:back

libs¶

• co-log
• named arguments
• refined — refinement types

  type ProperFraction = Refined (And (Not (LessThan 0)) (Not (GreaterThan 1))) Double

• Data.Sequence — list with fast append on both sides
• bound: Making de Bruijn Succ Less — convenient combinators for working with "locally-nameless" terms. These can be useful when writing a type checker, evaluator, parser, or pretty printer for terms that contain binders like forall or lambda
• Workflow — computations resumable from storage (!)
• capability — effects based on DerivingVia
• SMT:
  • concat (z3cat || smt example) — Compiling to categories — compiler plugin for translating normal Haskell functions (on standard types) to SMT, etc.
  • SBV: SMT Based Verification — translates Haskell functions on custom symbolic types
• Testing:
  • leancheck enumerative property-based testing core
    • extrapolate generalize counter-examples of properties
    • speculate discover properties
    • fitspec refine properties by mutation
  • hedgehog property
  • dejafu concurrency
  • type-spec: type level testing eDSL
  • should-not-typecheck
• Constraints:
  • https://github.com/ekmett/constraints
  • https://github.com/mikeizbicki/ifcxt
  • https://github.com/rampion/constraint-unions
• HKD:
  • https://github.com/jcpetruzza/barbies
  • https://github.com/i-am-tom/higgledy
  • https://hackage.haskell.org/package/rank2classes
• (Reversible) Parsing:
  • invertible-grammar by Eugene Smolanka, Sergey Vinokurov
    • http://hackage.haskell.org/package/invertible-grammar
  • Syntax by Paweł Nowak (Pavel Christof?) @2014 USED NOW
    • https://hackage.haskell.org/package/syntax
    • https://hackage.haskell.org/package/syntax-attoparsec
    • https://hackage.haskell.org/package/syntax-printer
    • https://hackage.haskell.org/package/semi-iso
  • Unparse by Tillmann Rendel and Klaus Ostermann @2010
    • https://www.informatik.uni-marburg.de/~rendel/unparse/ @2010
    • http://hackage.haskell.org/package/invertible-syntax @2010-2011
    • https://hackage.haskell.org/package/partial-isomorphisms @2011-2017
    • https://hackage.haskell.org/package/invertible @2016-2018
  • Fresnel, Prism-based unified parsers and pretty printers by Fraser Tweedale @2016
    • https://github.com/frasertweedale/hs-fresnel @2016-2017
  • (related) new optics library, alternative to lens @2019
    • Announcement
    • https://hackage.haskell.org/package/optics
    • https://hackage.haskell.org/package/optics-core
  • (related) Binary (ByteString-based) serialization by Lennart Kolmodin @2006-2019
    • https://hackage.haskell.org/package/binary

exts¶

• Existential Quantification
• RebindableSyntax — overloading built-in operators / do notation
• NullaryTypeClasses — global implementation of one thing
• DataKinds , TypeFamilies (+ GHC.TypeLits) — type-level annotations
  • Basic Type Level Programming in Haskell
  • Parsing type-level strings in Haskell
  • Servant, Type Families, and Type-level Everything
  • Haskell Type Names as Strings

other¶

• https://github.com/cohomolo-gy/haskell-resources
• ST Monad for imperative algorithms
• A Rosetta Stone for Haskell Abstractions Applicative, StateT, Lens
• Is it possible to place inequality constraints on haskell type variables?
• Practical uses of the Tardis monad?: 'build a packet ... where the fixed-length lengths and offsets of some variable length data are sent out before the actual data themselves'
• Comonadic builders
• GHC.Stack — can get code position for DSL
• GHC's Specializer: Much More Than You Wanted to Know
• Type Classes and Constraints
• Demystifying MonadBaseControl
• Cont:
  • Control.Monad.Trans.Cont
  • CC-delcont
  • Delimited continuations in Haskell
  • A Monadic Framework for DelimitedContinuations
  • Haskell's continuation monad
• Tagless Final / Overloading:
  • Introduction to Tagless Final
  • Tagless Final Encoding in Haskell
  • Typed final (aka, ``tagless-final'') style is a general method of embedding domain-specific languages (DSL)
  • Overloading lambda
• TypeFamilies:
  • Functional Dependencies & Type Families
  • Associated Types and Haskell
  • Partially applied type families GHC Proposal
  • On the arity of type families + Higher-order Type-level Programming in Haskell
  • Type Class Instances for Type-Level Lambdas in Haskell
  • Defunctionalization for Haskell Type Families
  • Haskell with only one type family
• HKD:
  • Functor Functors
  • Higher-Kinded Data
  • Deriving instances for higher-kinded data