Sequence.swift

//
//  Sequence.swift
//  ExSwift
//
//  Created by Colin Eberhardt on 24/06/2014.
//  Copyright (c) 2014 pNre. All rights reserved.
//

import Foundation

extension SequenceOf {

    func first () -> T? {
        var generator =  self.generate();
        return generator.next()
    }
    
    func skip (n:Int) -> SequenceOf<T> {
        var generator =  self.generate();
        for _ in 0..n {
            generator.next()
        }
        return SequenceOf(generator)
    }
    
    func skipWhile(condition:(T) -> Bool) -> SequenceOf<T> {
        var generator =  self.generate();
        var keepSkipping = true
        while keepSkipping {
            if let nextItem = generator.next() {
                keepSkipping = condition(nextItem)
            } else {
                keepSkipping = false
            }
        }
        return SequenceOf(generator)
    }
    
    func contains<T:Equatable> (item: T) -> Bool {
        var generator =  self.generate();
        while let nextItem = generator.next() {
            if nextItem as T == item {
                return true;
            }
        }
        return false
    }
}