Swift.Optional extensions

Optional_TJU.swift

//
//  Optional.swift
//  TonalKit
//
//  Created by TJ Usiyan on 11/4/14.
//  Copyright (c) 2014 Buttons and Lights LLC. All rights reserved.
//  https://gist.github.com/d9d826ed242b89ff2d85.git


extension Optional {
    internal func bind<U>(f: T -> U?) -> U? {
        if let x = self {
            return f(x)
        } else {
            return nil
        }
    }
}

func mapSome<S: SequenceType, T: ExtensibleCollectionType>
    (source: S, transform: (S.Generator.Element)->T.Generator.Element?) -> T {
        var result = T()
        for x in source {
            if let y = transform(x) {
                result.append(y)
            }
        }
        return result
}