jonschoning

The original code (~7.2s on my laptop).

import System.Random
import System.CPUTime

rainfall :: [Int] -> Int
rainfall xs = sum (zipWith (-) mins xs)

jonschoning

{-# LANGUAGE TypeSynonymInstances #-}

import Data.Monoid
import Data.Maybe

-- How much water does a "histogram" hold?
--
-- Inspired by Guy Steele's talk "Four Solutions to a Trivial Problem"
-- https://www.youtube.com/watch?v=ftcIcn8AmSY

jonschoning

What

A technique for writing parsers.

Why

• Easy to understand
• Generally applicable
• Full power of the programming language at your disposal
• Declarative

jonschoning

{-# LANGUAGE BangPatterns #-}
module Main where

import qualified Data.Text as Text
import Data.Text (Text, pack)
import Criterion.Main
import Test.QuickCheck.Arbitrary
import Test.QuickCheck
import Data.List
import qualified Data.Vector.Unboxed as U

jonschoning

{-# LANGUAGE ApplicativeDo           #-}
{-# LANGUAGE ConstrainedClassMethods #-}
{-# LANGUAGE ConstraintKinds         #-}
{-# LANGUAGE DataKinds               #-}
{-# LANGUAGE DeriveFunctor           #-}
{-# LANGUAGE DeriveGeneric           #-}
{-# LANGUAGE FlexibleContexts        #-}
{-# LANGUAGE FlexibleInstances       #-}
{-# LANGUAGE IncoherentInstances     #-}
{-# LANGUAGE InstanceSigs            #-}

jonschoning

{-# LANGUAGE DeriveFunctor, GADTs #-}
import Control.Monad.Writer
import Data.List (intercalate)
import Data.Foldable (traverse_)

data S m a where
    It         :: String -> m a       -> S m a
    Describe   :: String -> S m a     -> S m a
    Group      :: [S m a]             -> S m a
    BeforeEach :: m a -> S m (a -> b) -> S m b

jonschoning

Advanced Functional Programming with Scala - Notes

Copyright © 2017 Fantasyland Institute of Learning. All rights reserved.

1. Mastering Functions

A function is a mapping from one set, called a domain, to another set, called the codomain. A function associates every element in the domain with exactly one element in the codomain. In Scala, both domain and codomain are types.

val square : Int => Int = x => x * x

jonschoning

#!/usr/bin/env stack
{-
  stack
  --resolver lts-8.4
  --install-ghc
  runghc
  --package aeson
  --package aeson-casing
  --package base
  --package bytestring

jonschoning

{-# LANGUAGE MultiParamTypeClasses #-}
{-# LANGUAGE FlexibleInstances #-}
{-# LANGUAGE OverloadedStrings #-}
{-# LANGUAGE DataKinds #-}
{-# LANGUAGE DeriveGeneric #-}
{-# LANGUAGE TypeOperators #-}

module Sand where

import Data.Aeson

jonschoning

<Project>
    <ItemGroup>
        <Solution Include="*.sln" />
        <PublishProject Include="XXX.Mvc\XXX.Mvc.csproj" />
        <TestProject Include="**\*.Test*.*proj" Exclude="XXX.Tests.Shared\XXX.Tests.Shared.csproj" />
    </ItemGroup>

    <Target Name="Build">
        <MSBuild Projects="@(Solution)" Targets="Restore" ContinueOnError="ErrorAndStop" UnloadProjectsOnCompletion="true" UseResultsCache="false" />
        <MSBuild Projects="@(PublishProject)" Targets="Publish" Properties="Configuration=Release" ContinueOnError="ErrorAndContinue" />