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Globalcode–Open4education
Impactos no design utilizando programação funcional
Luiz [email protected] / @gutomcosta
twitter.com/gutomcosta github.com/gutomcosta
www.sagadoprogamador.com.br medium.com/saga-do-programador
orientação a objetos
conjunto de ideias
encapsulamento polimorfismo
objetos herançaestado ...
programação funcional
conjunto de ideias
funções higher-order functions
imutabilidade lazy evaluationrecursão ...
Dois estilos de escrita
código imperativo
Foco no “como fazer”
código declarativo
Foco no “o que fazer”
código declarativo
Foco no “o que fazer”
“When writing a modular program to solve a problem, one first divides the problem into subproblems, then solves the subproblems, and finally combines the solutions. The ways in which one can divide up the original problem depend directly on the ways in which one can glue solutions together.”
“Why functional programming matters” -John Hughes in Research topics in functional programming, 1990
“When writing a modular program to solve a problem, one first divides the problem into subproblems, then solves the subproblems, and finally combines the solutions. The ways in which one can divide up the original problem depend directly on the ways in which one can glue solutions together.”
“Why functional programming matters” -John Hughes in Research topics in functional programming, 1990
“When writing a modular program to solve a problem, one first divides the problem into subproblems, then solves the subproblems, and finally combines the solutions. The ways in which one can divide up the original problem depend directly on the ways in which one can glue solutions together.”
“Why functional programming matters” -John Hughes in Research topics in functional programming, 1990
..argue in the remainder of this paper that functional languages provide two new, very important kinds of glue.
“Why functional programming matters” -John Hughes in Research topics in functional programming, 1990
higher order function lazy evaluation
building blocks
first class functions
uma variável?
invocando uma função
função como parâmetro
invoca a função
mesma função variando comportamento
dados e funções separados
higher order functionuma funcão que recebe outra função como
argumento ou retorna uma função
Como First Class Functions e Higher
Order Functions podem impactar nas decisões
de design?
OO foco na estruturaComo substituir uma implementação em
runtime?
FP foco na transformaçãotransformação?
listas, map, reduce, filter
map
capitalize capitalize capitalize
Jose Paulo Luiz
jose luizpaulo
TextTextTextText
clojure.string
focus on results, not steps
“Functional Thinking” -Neal Ford - IBM Developer Works series
Filter clojure.string
1 2 3 4 5 6 7 8 9
ArgentumAnálise de Candlesticks, bolsa de valores
Candlesticks
ArgentumDomain Model
como representar os conceitos?
Negócio, Candlestick
define uma abstração
dados e funções separados
decompose an algorithm into functions that are simple, meaningful and useful.
“Tutorial on Good Lisp Programming Style” -Peter Norvig in 1992
decompose an algorithm into functions that are simple, meaningful and useful.
“Tutorial on Good Lisp Programming Style” -Peter Norvig in 1992
decomposição
invariantes
decomposição
dependência de outro namespace
ArgentumGeração de gráfico com indicadores define uma
abstração
define comportamentos diferentes
como variar o comportamento?
declara as funções
compondo funções
higher order functions
decomposição de função
calculando a média móvel
com diferentes building blocks, é
preciso repensar as decisões de design
OO e FP Juntos?
Functional in the small, OO in the large.“Tell Above, and Ask Below - Hybridizing OO and Functional design”
-Michael Feathers, blog post
Functional Core, imperative shell.“Destroy all software - episode 72”
-Gary Bernhardt, destroy on software screen cast series
conclusão
Functional Programming is more a mindset than a particular set
of tools or languages.“Functional Thinking”
-Neal Ford - IBM Developer Works series
Obrigado
ReferênciasSICP - http://mitpress.mit.edu/sicp/full-text/book/book.html
Why functional programming matters - http://www.cs.kent.ac.uk/people/staff/dat/miranda/whyfp90.pdf
Clojure - http://clojure.org/
Functional Thinking - http://www.ibm.com/developerworks/java/library/j-ft1/index.html
Tell Above, and ask Below - http://michaelfeathers.typepad.com/michael_feathers_blog/2012/03/tell-above-and-ask-below-hybridizing-oo-and-functional-design.html
Functional Core, imperative shell - https://www.destroyallsoftware.com/screencasts/catalog/functional-core-imperative-shell
Tutorial on good lisp programming style - http://www.cs.umd.edu/~nau/cmsc421/norvig-lisp-style.pdf
