Porque aprender haskell me fez um programador

python melhor?

@gustavopintogustavo@entropie.com.br

Porque aprender haskell me fez um programador

python melhor?

@gustavopintogustavo@entropie.com.br

Baseado em fatos reais

Gustavo Pinto

2004 - belém, grad, php, sh2006 - amazontic, java, xp2008 - curitiba, msc, python2009 - aprioriti, xp, scrum2011 - recife, phd, haskell2012 - entropie, lean, scala

Belém

Belém

Belém

Belém

Belém

Belém

DISCLAIMER

Não tem código

Não tem código¬¬''

Mentira, tem mas épouquinho :-)

1912 ~ 1954

1912 ~ 19541936

1912 ~ 19541936

ON COMPUTABLE NUMBERS, WITH AN APPLICATION

TO THE ENTSCHEIDUNGS

PROBLEM

ON COMPUTABLE NUMBERS, WITH AN APPLICATION

TO THE ENTSCHEIDUNGS

PROBLEM

ON COMPUTABLE NUMBERS, WITH AN APPLICATION

TO THE DECISION PROBLEM

1903 ~1995

1903 ~19951936

1903 ~19951936

AN UNSOLVABLE PROBLEM OF ELEMENTARY

NUMBER THEORY

1936

1936

Church-Turing thesis

Church-Turing thesis

Church-Turing thesis

Equivalentes

Algumas features:

● Pure functions● Functions as first-class objects● No side effects

Algumas features:

● Pure functions● Functions as first-class objects● No side effects

Concurrency Friendly

Great.. But, what about Python??

Python functional

Is python functional?

Is python functional?

I have never considered Python to be heavily influenced by functional

languages, no matter what people say or think. I was much more familiar with imperative languages such as C and

Algol 68 and although I had made functions first-class objects, I didn't view

Python as a functional programming language. However, earlier on, it was

clear that users wanted to do much more with lists and functions.

http://python-history.blogspot.com.br/2009/04/origins-of-pythons-functional-features.html

I have never considered Python to be heavily influenced by functional

languages, no matter what people say or think. I was much more familiar with imperative languages such as C and

Algol 68 and although I had made functions first-class objects, I didn't view

Python as a functional programming language. However, earlier on, it was

clear that users wanted to do much more with lists and functions.

http://python-history.blogspot.com.br/2009/04/origins-of-pythons-functional-features.html

I have never considered Python to be heavily influenced by functional

languages, no matter what people say or think. I was much more familiar with imperative languages such as C and

Algol 68 and although I had made functions first-class objects, I didn't view

Python as a functional programming language. However, earlier on, it was

clear that users wanted to do much more with lists and functions.

http://python-history.blogspot.com.br/2009/04/origins-of-pythons-functional-features.html

I have never considered Python to be heavily influenced by functional

languages, no matter what people say or think. I was much more familiar with imperative languages such as C and

Algol 68 and although I had made functions first-class objects, I didn't view

Python as a functional programming language. However, earlier on, it was

clear that users wanted to do much more with lists and functions.

http://python-history.blogspot.com.br/2009/04/origins-of-pythons-functional-features.html

I see list and functions

hack, hack

if god exists: atepassar**2

search_list = lambda l,e : [ [ idx for idx, element in enumerate(l) if element ==

element_f ] for element_f in e]

search_list = lambda l,e : [ [ idx for idx, element in enumerate(l) if element ==

element_f ] for element_f in e]

List comprehensionA basic comprehension for a set that contains the first ten even natural numbers is

The part before the pipe is called the output function, x is the variable, N is the input set and x <= 10 is the predicate. That means that the set contains the doubles of all natural numbers that satisfy the predicate.

http://learnyouahaskell.com/starting-out#im-a-list-comprehension

List comprehensionA basic comprehension for a set that contains the first ten even natural numbers is

The part before the pipe is called the output function, x is the variable, N is the input set and x <= 10 is the predicate. That means that the set contains the doubles of all natural numbers that satisfy the predicate.

http://learnyouahaskell.com/starting-out#im-a-list-comprehension

List comprehensionA basic comprehension for a set that contains the first ten even natural numbers is

>>> [i for x in range (0, 100) if x > 10]

http://learnyouahaskell.com/starting-out#im-a-list-comprehension

List comprehensionA basic comprehension for a set that contains the first ten even natural numbers is

>>> [i for x in range (0, 100) if x > 10]>>> [[row[i] for row in matrix] for i in range(4)]

http://learnyouahaskell.com/starting-out#im-a-list-comprehension

List comprehensionA basic comprehension for a set that contains the first ten even natural numbers is

>>> [i for x in range (0, 100) if x > 10]>>> [[row[i] for row in matrix] for i in range(4)]>>> dict([(i, chr(65+i)) for i in range(4)])

http://learnyouahaskell.com/starting-out#im-a-list-comprehension

List comprehensionA basic comprehension for a set that contains the first ten even natural numbers is

>>> [i for x in range (0, 100) if x > 10]>>> [[row[i] for row in matrix] for i in range(4)]>>> dict([(i, chr(65+i)) for i in range(4)])

http://learnyouahaskell.com/starting-out#im-a-list-comprehension

Sou foda

search_list = lambda l,e : [ [ idx for idx, element in enumerate(l) if element ==

element_f ] for element_f in e]

LambdaLambdas are basically anonymous functions that are used because we need some functions only once. Normally, we make a lambda with the sole purpose of passing it to a higher-order function.

http://learnyouahaskell.com/higher-order-functions#lambdas

LambdaLambdas are basically anonymous functions that are used because we need some functions only once. Normally, we make a lambda with the sole purpose of passing it to a higher-order function.

http://learnyouahaskell.com/higher-order-functions#lambdas

Lambda>>> lambda x: x % 2

http://learnyouahaskell.com/higher-order-functions#lambdas

Lambda>>> is_even = lambda x: x % 2

http://learnyouahaskell.com/higher-order-functions#lambdas

Lambda>>> is_even = lambda x: x % 2>>> is_even<function <lambda> at 0x2a3d050>

http://learnyouahaskell.com/higher-order-functions#lambdas

search_list = lambda l,e : [ [ idx for idx, element in enumerate(l) if element ==

element_f ] for element_f in e]

Built-in Functions>>> for mes in enumerate (['jan', 'fev', 'mar']):... print mes(0, 'jan')(1, 'fev')(2, 'mar')

Built-in Functions>>> for mes in enumerate (['jan', 'fev', 'mar']):... print mes(0, 'jan')(1, 'fev')(2, 'mar')

outras built-in functions: ● filter● map● reduce

Built-in Functions>>> for mes in enumerate (['jan', 'fev', 'mar']):... print mes(0, 'jan')(1, 'fev')(2, 'mar')

outras built-in functions: ● filter● map● reduce

Funções de alta ordem

Filterfilter(...)

filter(function or None, sequence) -> list, tuple or string

Return those items of sequence for which function(item) is true. [....]

>>> filter(lambda x: x % 2 == 0, range(10))

Filterfilter(...)

filter(function or None, sequence) -> list, tuple or string

Return those items of sequence for which function(item) is true. [....]

>>> is_even = lambda x: x % 2 == 0>>> filter(is_even, range(10))

Mapmap(...)

map(function, sequence[, sequence, ...]) -> list

Return a list of the results of applying the function to the items of the argument sequence(s). [....]

>>> map(lambda s: s.upper(), ['a', 'b', 'c'])

Reducereduce(...)

reduce(function, sequence[, initial]) -> value

Apply a function of two arguments cumulatively to the items of a sequence, from left to right, so as to reduce the sequence to a single value. [....]

>>> reduce(lambda x,y: x * y, range(1, 4))>>> reduce(lambda x, y: x + y, ['a', 'b', 'c', 'd'])

Sua High Order Functiondef f(x):

return x + 1

def g(function, x):return function(x) + function (x + 1)

print g(f, 1)

Sua High Order Functiondef f(x):

return x + 1

def g(function, x):return function(x) + function (x + 1)

print g(f, 1)

not bad

Porque aprender haskell me fez um programador

python melhor?

Consegui entendermelhor o

código do Marcel!

Consegui entender melhor o código

de outras pessoas!

Consegui entender melhor a minha

linguagem!

Consegui entender melhor o meu

framework!

Resumindo

Domine sua linguagem

Evolua com a sua linguagem

Domine outras linguagens(Tanto quanto)

Entenda que linguagens são

escolhas

Seja o principal crítico das suas

escolhas

Para saber mais:

from functional import *

OBRIGADO!

@gustavopintogustavo@entropie.com.br