mkhl

extension Array {
  mutating func shuffle() {
    if self.count < 2 { return }
    for i in 0..<self.count {
      let j = Int(arc4random_uniform(UInt32(self.count - i))) + i
      if i != j {
        swap(&self[i], &self[j])
      }
    }
  }

mkhl

extension CollectionType {
  func indexBy<Key: Hashable>(keyFunction: (Generator.Element) -> Key) -> [Key: [Generator.Element]] {
    var map: [Key: [Generator.Element]] = [:]
    for element in self {
      let key = keyFunction(element)
      var elements = map[key] ?? []
      elements.append(element)
      map[key] = elements
    }
    return map

mkhl

extension Dictionary {
  mutating func merge(other: [Key: Value], by combine: (Value, Value) -> Value) {
    for (key, newValue) in other {
      if let oldValue = self[key] {
        self[key] = combine(oldValue, newValue)
      } else {
        self[key] = newValue
      }
    }
  }

mkhl

import PromiseKit

extension CollectionType {
  func traverse<T>(transform: Generator.Element -> Promise<T>) -> Promise<[T]> {
    return Promise { fulfill, reject in
      var accumulator: [T] = []
      var generator = self.generate()
      func recurse() {
        guard let next = generator.next() else {
          fulfill(accumulator)

mkhl

func permutations<Sequence: SequenceType>(items: Sequence) -> [[Sequence.Generator.Element]] {
	return items.reduce([[]]) { (perms, item) in
		return perms.flatMap { perm in
			return (0 ... perm.count).map { i in
				var copy = perm
				copy.insert(item, atIndex: i)
				return copy
			}
		}
	}

mkhl

func power<Sequence: SequenceType>(items: Sequence) -> [[Sequence.Generator.Element]] {
  return items.reduce([[]]) { (arrays, item) in
    return arrays + arrays.map { (var array) in
      array.append(item)
      return array
    }
  }
}

mkhl

#!/usr/bin/env ruby -w

require "rubygems"
require "nokogiri"
require "open-uri"

PROGRAM_BASE = File.basename $PROGRAM_NAME

def usage
  puts <<-USAGE

mkhl

extension NSComparisonResult {
  init() {
    self = .OrderedSame
  }

  var isAscending: Bool {
    return self == .OrderedAscending
  }

  var isDescending: Bool {

mkhl

#!/bin/sh
git add --update -- "$@"
git commit --message="trash -- $(date)" -- "$@"
git reset --soft HEAD^
git reset --quiet -- "$@"
git checkout -- "$@"

mkhl

cd $(seq -f .. -s / 1 ${1:-1})
cd $(jot -b .. -s / ${1:-1})
# using jot(1) is shorter, and doesn't add a trailing /
# but as far as I recall, jot(1) isn't part of GNU userland