Foward'|>'Pipeh"p://github.com/jarsen/Pipes

Method'Chaining[1,2,3,4,5].filter(isEven).map({$0 * 3}).reduce(0, combine: +) // 18

Method'Chaining

Array(1...5) .filter(isEven) .map({$0 * 3}) .reduce(0, combine: +) // 18

Func%on!Chaining

reduce(map(filter(1...5, isEven), {$0 * 3}), 0, +) // 18

"Hello" |> println

• Meet%the%Forward%Pipe%Operator%|>

• Popular%in%languages%such%as%F#%and%Elixir.

• Simply%applies%le>%hand%side%of%expression%as%first%argument%of%funcAon%on%the%right

The$Forward$Pipe$Operator

2 |> increment // 35 |> (divide, 10) // 0.510 |> (divide, 5) // 2

Data$Pipelines

// the result of each step becomes first arg in the next1...5|> (filter, isEven) // [2, 4]|> (map, {$0 * 3}) // [6, 12]|> (reduce, 0, +) // 18

Data$Pipelines

students// filter to students with last name L*|> (filter, { $0.lastName.hasPrefix("L") }// get list of all their first names|> (map, Student.firstName)// make all the names uppercase|> (map, String.uppercaseString)

Op#onal<T>+Method+Chaininglet animalNoiseMap = ["cow":"moo", "dog":"woof", "cat":"meow"]

animalNoiseMap["dog"]?.uppercaseString // .Some("WOOF")animalNoiseMap["fox"]?.uppercaseString // .None

Op#onal<T>+Func%on+Chaininglet animalNoiseMap = ["cow":"moo", "dog":"woof", "cat":"meow"]

map(animalNoiseMap["dog"]) { count(filter($0, isVowel)) } // .Some(2)map(animalNoiseMap["fox"]) { count(filter($0, isVowel)) } // .None

Op#onal<T>+Pipeline

animalNoiseMap["dog"] // .Some("woof")|> (filter, isVowel) // .Some(["o", "o"])|> count // .Some(2)

Op#onal<T>+Pipeline

animalNoiseMap["fox"] // .None|> (filter, isVowel) // .None|> count // .None

Op#onal<T>+Pipeline

[2, 4, 6, 8, 10]|> (map, increment) // [3, 5, 7, 9, 11]|> (find, 7) // .Some(2)|> isEven // .Some(true)

Op#onal<T>+Pipeline

[2, 4, 6, 8, 10]|> (map, increment) // [3, 5, 7, 9, 11]|> (find, 6) // .None|> isEven // .None

Result<T>*Pipeline!// uses https://github.com/antitypical/Result

func escapeInput(string: String) -> String { ... }

func readFile(fileName: String) -> Result<String> { ... }

func processText(string: String) -> String { ... }

let processedText = inputFileName |> escapeInput |> readFile |> processText

Experimental,Forward,Pipes

|>> // apply as second argument|>>> // apply as third argument|< // apply as last argument

Benefits

• pipelines(are(about(composi'on,(encouraging(small,(pure,(reusable(func3ons

• fewer("temporary"(variables(intended(for(use(on(next(line

• data(pipeline(reads(like(a(nice(list

• code(for(handling(values,(Optional<T>(and(Result<T>(is(the(same:(avoid(if-lets(and(switches(and(without(knowledge(of(monad(kung>fu

Non$Muta)ng+Helpers

Pure%versions%of%everything%in:

• ExtensibleCollectionType

• RangeReplaceableCollectionType

• MutableCollectionType

• Mutable)dic-onary)stuff

Currying// curry the first argument at the endfunc map<S: SequenceType, T>(f: S.Generator.Element->T)(seq: S) -> [T] {...}

1...5|> filter(isEven) // [2, 4]|> map({$0 * 3}) // [6, 12]|> reduce(0, +) // 18

Non$Muta)ng+Helpers

Pipes&contains&curried&versions&of:

• map,#filter,#reduce

• ExtensibleCollectionType

• RangeReplaceableCollectionType

• MutableCollectionType

• Mutable#dic.onary#stuff

h"p://github.com/jarsen/PipesFeedback(/(Pull(Requests(much(appreciated

@jarsen(on(twi-er