Runes

Infix operators for monadic functions in Swift

Code Quality Rank: L5

Programming language: Swift

License: MIT License

Tags: Utility    

Latest version: v5.1.0

README

Indecipherable symbols that some people claim have actual meaning.

Please see [the documentation] for [installation] instructions.

What's included?

Importing Runes introduces several new operators and one global function that correspond to common Haskell typeclasses:

Functor

• <^> (pronounced "map")

Applicative Functor

• <*> (pronounced "apply")
• <* (pronounced "left sequence")
• *> (pronounced "right sequence")
• pure (pronounced "pure")

Alternative

• <|> (pronounced "alternate")
• empty (pronounced "empty")

Monad

• >>- (pronounced "flatMap") (left associative)
• -<< (pronounced "flatMap") (right associative)
• >-> (pronounced "Monadic compose") (left associative)
• <-< (pronounced "Monadic compose") (right associative)

Implementations

We also include default implementations for Optional and Array with the following type signatures:

// Optional+Functor:
public func <^> <T, U>(f: T -> U, x: T?) -> U?

// Optional+Applicative:
public func <*> <T, U>(f: (T -> U)?, x: T?) -> U?
public func <* <T, U>(lhs: T?, rhs: U?) -> T?
public func *> <T, U>(lhs: T?, rhs: U?) -> U?
public func pure<T>(x: T) -> T?

// Optional+Alternative:
public func <|> <T>(lhs: T?, rhs: T?) -> T?
public func empty<T>() -> T?

// Optional+Monad:
public func >>- <T, U>(x: T?, f: T -> U?) -> U?
public func -<< <T, U>(f: T -> U?, x: T?) -> U?
public func >-> <T, U, V>(f: T -> U?, g: U -> V?) -> T -> V?
public func <-< <T, U, V>(f: U -> V?, g: T -> U?) -> T -> V?

// Array+Functor:
public func <^> <T, U>(f: T -> U, x: [T]) -> [U]

// Array+Applicative:
public func <*> <T, U>(fs: [T -> U], x: [T]) -> [U]
public func <* <T, U>(lhs: [T], rhs: [U]) -> [T]
public func *> <T, U>(lhs: [T], rhs: [U]) -> [U]
public func pure<T>(x: T) -> [T]

// Array+Alternative:
public func <|> <T>(lhs: [T], rhs: [T]) -> [T]
public func empty<T>() -> [T]

// Array+Monad:
public func >>- <T, U>(x: [T], f: T -> [U]) -> [U]
public func -<< <T, U>(f: T -> [U], x: [T]) -> [U]
public func >-> <T, U, V>(f: T -> [U], g: U -> [V]) -> T -> [V]
public func <-< <T, U, V>(f: U -> [V], g: T -> [U]) -> T -> [V]

// Result+Functor:
public func <^> <T, U, E>(f: (T) -> U, a: Result<T, E>) -> Result<U, E>

// Result+Applicative:
public func <*> <T, U, E>(f: Result<(T) -> U, E>, a: Result<T, E>) -> Result<U, E>
public func <* <T, U, E>(lhs: Result<T, E>, rhs: Result<U, E>) -> Result<T, E>
public func *> <T, U, E>(lhs: Result<T, E>, rhs: Result<U, E>) -> Result<U, E>
public func pure<T, E>(_ a: T) -> Result<T, E>

// Result+Alternative:
public func <|> <T, E>(lhs: Result<T, E>, rhs: @autoclosure () -> Result<T, E>) -> Result<T, E>

// Result+Monad:
public func >>- <T, U, E>(a: Result<T, E>, f: (T) -> Result<U, E>) -> Result<U, E>
public func -<< <T, U, E>(f: (T) -> Result<U, E>, a: Result<T, E>) -> Result<U, E>
public func >-> <T, U, V, E>(f: @escaping (T) -> Result<U, E>, g: @escaping (U) -> Result<V, E>) -> (T) -> Result<V, E>
public func <-< <T, U, V, E>(f: @escaping (U) -> Result<V, E>, g: @escaping (T) -> Result<U, E>) -> (T) -> Result<V, E>

Contributing

See the [CONTRIBUTING] document. Thank you, contributors!

License

Runes is Copyright (c) 2015 thoughtbot, inc. It is free software, and may be redistributed under the terms specified in the LICENSE file.

About

Runes is maintained and funded by thoughtbot, inc. The names and logos for thoughtbot are trademarks of thoughtbot, inc.

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