PLC - Paradigmas de Linguagens computacionais | Programming Pparadigms

My lessons or whatever to discipline Programming Paradigms at CIn - UFPE.

Tutorial

Open GHCI inside workspace folder typing ghci on terminal $ cd /myworkspace && ghci To load a file type: $ :load file.hs Now you just need call a function in file.hs $ myFunc

List generators

[0..5] ---> [0,1,2,3,4,5]

List functions

take

take 3 [1,2,3,4,5,6]   --> [1,2,3]

drop

drop 3 [1,2,3,4,5,6]   --> [4,5,6]

map

map func [1,2,3]       -->  [func 1, func 2, func 3]

filter

filter func [1,2,3]    --> [1,2] if satf func
filter (>=2) [1,2,3]   --> [2,3]

reverse

reverses [1,2,3,4]       --> [4,3,2,1]

zip

zip [a,b] [c,d]        --> [(a,c), (c,d)]

fmap

fmap (*2)  [1,2,3]

foldr or foldl (right or left)

foldr (+) 0 (fmap (+2) [1,2,3])    --> 12

foldr1 no have base case

foldr1 (+) [1,2,3]      --> 6

elem

elem 4 [1,2,3,4,5,6]      --> True
elem 9 [1,2,3,4,5,6]      --> False

maximum and minimum

maximum [1,2,3,4,5,6]      --> 6
minimum [1,2,3,4,5,6]      --> 1

List Comprehension

[ ( op item ) | item <- [1,2,3], conditions]           ---> [op 1, op 2, op 3] if condition
[ (i1, i2) | i1 <- [1,2], i2 <- [1,2], conditions]     ---> [(1,1), (1,2), (2,1), (2,2)] if condition

Where

func :: t -> t
func _ = _
func x = anotherFunc x
    where anotherFunc _ = _
          anotherFunc x = x

Let

can be used to generate var

Class

Instance

data Temperature = Celsius Float | Fahrenheit Float | Kelvin Float

showTmp :: Temperature -> String showTmp (Celsius x) = "Temp: " ++ show x ++ "º C" showTmp (Fahrenheit x) = "Temp: " ++ show x ++ "° F" showTmp (Kelvin x) = "Temp: " ++ show x ++ " K"

toKelvin :: Temperature -> Float toKelvin (Celsius x) = (x + 273) toKelvin (Fahrenheit x) = ((((x - 32) / 9) * 5) + 273) toKelvin (Kelvin x) = x

cmpTmp :: (Float -> Float -> Bool) -> Temperature -> Temperature -> Bool cmpTmp f (Kelvin x) (Kelvin y) = f x y cmpTmp f (Celsius x) (Celsius y) = f x y cmpTmp f (Fahrenheit x) (Fahrenheit y) = f x y cmpTmp f (Kelvin x) (Celsius y) = f x (toKelvin (Celsius y)) cmpTmp f (Kelvin x) (Fahrenheit y) = f x (toKelvin (Fahrenheit y)) cmpTmp f (Celsius x) (Fahrenheit y) = f (toKelvin (Celsius x)) (toKelvin (Fahrenheit y)) cmpTmp f (Celsius x) (Kelvin y) = cmpTmp f (Kelvin y) (Celsius x) cmpTmp f (Fahrenheit x) (Kelvin y) = cmpTmp f (Kelvin y) (Fahrenheit x) cmpTmp f (Fahrenheit x) (Celsius y) = cmpTmp f (Celsius y) (Fahrenheit x)

instance Show Temperature where show = showTmp

instance Eq Temperature where (==) = (cmpTmp (==))

instance Ord Temperature where (<=) = (cmpTmp (<=)) (>) x y = (cmpTmp (>)) y x

ovictoraurelio/plc