Currying

Lightning talk de 5 minutos sobre Currying em Português.

Transcript

1. TDAH Talks 2016 - E01 Fabricio C Zuardi (@fczuardi) Assunto: Currying 1 / 21
2. Currying 2 / 21
3. Curry photo: curry-powder-590 by Oregon State University 3 / 21
4. Curry photo: MacTutor History of Mathematics archive 4 / 21
5. Haskell Brook Curry There are three programming languages named after him, Haskell, Brook and Curry, as well as the concept of currying, a technique used for transforming functions in mathematics and computer science. source: Haskell_Curry @ Wikipedia 5 / 21
6. Currying is… "…the technique of translating the evaluation of a function that takes multiple arguments (or a tuple of arguments) into evaluating a sequence of functions, each with a single argument. It was introduced by Gottlob Frege, developed by Moses Schönfinkel, and further developed by Haskell Curry." -- Wikipedia source: Currying - Wikipedia 6 / 21
7. Currying is… "…the process of transforming a function that takes multiple arguments into a function that takes just a single argument and returns another function if any arguments are still needed." -- Haskell Wiki source: Currying - Haskell Wiki 7 / 21
8. …a technique for postponing a problem. "…um jeito de empurrar problemas pra frente." 8 / 21
9. Curried function "A function that will return a new function until it receives all it's arguments" -- Brian Lonsdorf source: Hey Underscore, You're Doing It Wrong! 9 / 21
10. Partially-aplied function "A function that will return a new function until it receives all it's arguments" -- Brian Lonsdorf source: Hey Underscore, You're Doing It Wrong! 10 / 21
11. Example (javascript) c o n s t s u m A B = f u n c t i o n ( a , b ) { r e t u r n a + b ; } s u m A B ( 1 , 2 ) ; / / 3 11 / 21
12. Example (javascript) c o n s t c u r r i e d S u m A B = f u n c t i o n ( a ) { r e t u r n f u n c t i o n ( b ) { r e t u r n a + b ; } } c u r r i e d S u m A B ( 3 ) ( 4 ) ; / / 7 12 / 21
13. Example (javascript) c o n s t s u m A B = ( a , b ) = > a + b ; s u m A B ( 1 , 2 ) ; / / 3 c o n s t c u r r i e d S u m A B = ( a ) = > ( b ) = > a + b ; c u r r i e d S u m A B ( 3 ) ( 4 ) ; / / 7 c u r r i e d S u m A B ( 1 ) ( 1 ) ; / / 2 13 / 21
14. (0)(0) 14 / 21
15. wtf(0)(0) 15 / 21
16. Example step-by-step (javascript) c o n s t c u r r i e d S u m A B = ( a ) = > ( ( b ) = > a + b ) ; c o n s t s u m 3 = c u r r i e d S u m A B ( 3 ) ; t y p e o f s u m 3 ; / / f u n c t i o n s u m 3 ; / / f u n c t i o n ( b ) { r e t u r n a + b ; } s u m 3 ( 4 ) ; / / 7 16 / 21
17. curry (Ramda.js) Returns a curried equivalent of the provided function. The curried function has two unusual capabilities. First, its arguments needn't be provided one at a time. If f is a ternary function and g is R.curry(f), the following are equivalent: g(1)(2)(3) g(1)(2, 3) g(1, 2)(3) g(1, 2, 3) 17 / 21
18. curriedSumAB (Ramda.js) c o n s t s u m A B = ( a , b ) = > a + b ; c o n s t c u r r i e d S u m A B = c u r r y ( s u m A B ) ; c u r r i e d S u m A B ( 1 , 2 ) c u r r i e d S u m A B ( 3 , 4 ) c u r r i e d S u m A B ( 3 ) ( 4 ) 18 / 21
19. E pq isso é útil? 19 / 21
20. Function Composition 20 / 21
21. Obrigado! 21 / 21