gustavofranke

package option

import org.scalatest.funsuite.AnyFunSuite

/**
 * show some scala language features that, if you come from other languages, they might be unknown to you.
 *
 * Like last week, we'll play with the REPL, then turn our findings into tests.
 *
 * I'll use scala-test to automate this process,

gustavofranke

module Geometry.Cube  
( volume  
, area  
) where  
  
import qualified Geometry.Cuboid as Cuboid  
  
volume :: Float -> Float  
volume side = Cuboid.volume side side side  
  

gustavofranke

Data.Time> :t "foo"
"foo" :: [Char]
Data.Time> :set -XOverloadedStrings
Data.Time> :t "foo" "foo" :: Data.String.IsString p => p

gustavofranke

-- stack repl --package <package-name>

-- stack repl --package time
> import Data.Time
Data.Time> getCurrentTime
2020-10-17 15:03:15.521782 UTC
Data.Time> utctDay <$> getCurrentTime
2020-10-17
Data.Time> today <- utctDay <$> getCurrentTime
Data.Time> today

gustavofranke

package cipher

def lowers(xs: String): Int =
  xs.filter(x => x >= 'a' && x <= 'z').length

def count(x: Char, xs: String): Int =
  xs.toList.filter(x0 => x == x0).length

def positions[A](x: A, xs: List[A]): List[Int] =
  for

gustavofranke

package playground
// https://www.youtube.com/watch?v=xpz4rf1RS8c
// 01. functional effects

// Console - Model 1
sealed trait Console1 { self =>
  def +(that: Console1): Console1 = Sequence1(self, that)
}
final case class Print1(line: String) extends Console1
final case class Sequence1(first: Console1, second: Console1) extends Console1

gustavofranke

-- 1.7Exercises
-- 1.Give another possible calculation for the result of double (double 2).
double x = x + x

another = (double . double) 2

-- 2.Show that sum [x] = x for any number x.
ex2 :: (Eq a, Num a) => a -> Bool
ex2 x = sum [x] == x

gustavofranke

module Main where
import Control.Monad
import Control.Monad.Except
import System.Environment
import Text.ParserCombinators.Parsec hiding (spaces)

main :: IO ()
main = do
    args   <- getArgs
    evaled <- return $ liftM show $ readExpr (args !! 0) >>= eval

gustavofranke

module Database where

import System.Random (getStdRandom, randomR)
import Project

getBudget :: ProjectId -> IO Budget
getBudget _ = do
    income      <- Money <$> getStdRandom (randomR (0, 10000))
    expenditure <- Money <$> getStdRandom (randomR (0, 10000))
    pure Budget { budgetIncome = income, budgetExpenditure = expenditure}

gustavofranke

-- from
-- https://www.youtube.com/watch?v=lxjIUWGMUqE
-- Haskell at Work - Validation with Smart Constructors

module SerialNumber 
    ( SerialNumber
    , ValidataionError(..)
    , makeSerialNumber   
    , renderSerialNumber 
    ) where