Why I care about Haskell

by Nuno Alexandre

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Why I care about Nuno Alexandre nunoalexandre.com

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Overview 1. Premise 2. Why Haskell 3. From OOP to FP 4. Haskell Goodies 5. Wrap up 6. Q & A

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To Digest

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Why Haskell • functional thinking • mathematical based • a great type system • beautiful code • features 20 years ahead • rigorous & constrained • challenging

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From OOP to FP • Objects vs Functions • A matter of granularity

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From OOP to FP

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From OOP to FP • OO starts low and abstracts as necessary PeopleGroup Group *BaseClass PersonUtils

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From OOP to FP • In FP abstraction is the starting point • Reusable • Decoupled • Composition

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First Look

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Haskell Goodies • Purely functional • Laziness • Pattern Matching • Lambdas & Currying

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Purely Functional • Immutability • Purity • Explicit side-effects through Monads

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Purely Functional Immutability

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Purely Functional Purity  • same result for same arguments • no side-effects • referential transparency

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Purely Functional Explicit side-effects through Monads http://nunoalexandre.com/2016/10/13/the-monad-pattern

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Laziness • Idle until necessary otherwise • Declarative thinking

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Pattern Matching • http://nunoalexandre.com/2016/11/17/the-joy-of-pattern-matching

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Pattern Matching • On custom types

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Pattern Matching • On lists

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Pattern Matching • On polymorphism

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Pattern Matching • On binding

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Lambdas • anonymous & Turing-complete http://nunoalexandre.com/2016/09/16/love-the-lambda

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Currying • beautiful partial applications http://nunoalexandre.com/2016/09/13/a-taste-of-curry-an-apologetic

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Drawbacks • Space complexity is hard to debug • Not such great tooling • Memory consumption • Hard to learn independently

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Conclusion • Languages are not just tools • Think different • Purity is beauty • Scientiﬁc certainty

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Advanced Topics • Monads & Monads Transformers • Functors, Applicative Functors and Monoids • Category Theory