jagbolanos

--Proposed solutions to problems 87,88 and 89 of "99 Haskell Problems"
--Not optimal but they work
--If you know haskell and want to solve some problems there are some missing at:
--http://www.haskell.org/haskellwiki/99_questions/80_to_89

import Data.List

type Node = Int
type Edge = (Node,Node)
type Graph = ([Node],[Edge])

markd2

#import <Foundation/Foundation.h>

@interface BNRDiggyDict : NSObject

// React to object indexing.  Would be nice to have a @protocol for this
- (id) objectForKeyedSubscript: (id) key;
- (void) setObject: (id) thing  forKeyedSubscript: (id<NSCopying>) key;

// And for fun, it also can react to scalar indexing.
// Returns the N'th key of the top-level collection.

domenic

This article has been given a more permanent home on my blog. Also, since it was first written, the development of the Promises/A+ specification has made the original emphasis on Promises/A seem somewhat outdated.

You're Missing the Point of Promises

Promises are a software abstraction that makes working with asynchronous operations much more pleasant. In the most basic definition, your code will move from continuation-passing style:

getTweetsFor("domenic", function (err, results) {
 // the rest of your code goes here.

benjchristensen

/**
 * Non-blocking method that immediately returns the value
 * if available or  uses a thread to fetch the value and 
 * callback via `onNext()` when done. 
 */
def Observable<T> getData(int id) {
    if(availableInMemory) {
        // if data available return immediately with data
        return Observable.create({ observer ->
            observer.onNext(valueFromMemory);

egonSchiele

import Control.Monad
import Control.Concurrent
import Control.Concurrent.STM
import System.Random
import Text.Printf

-- Forks
type Fork = TMVar Int
 
newFork :: Int -> IO Fork

egonSchiele

require 'rubygems'
require 'celluloid'

class Waiter
  include Celluloid
  FORK_FREE = 0
  FORK_USED = 1
  attr_reader :philosophers
  attr_reader :forks
  attr_reader :eating

egonSchiele

require 'thread'

class Waiter
  def initialize
    @mutex = Mutex.new
  end

  def can_eat? philosopher
    left = philosopher.left_fork
    right = philosopher.right_fork

egonSchiele

import Control.Monad.Reader

hello :: Reader String String
hello = do
    name <- ask
    return ("hello, " ++ name ++ "!")

bye :: Reader String String
bye = do
    name <- ask

leroux

Haskell Resources

• Learning Haskell
• Learn You a Haskell for Great Good
  • Learn You A Haskell Exercises
• Real World Haskell
• FPComplete's School of Haskell
• Haskell Wikibook
• Write Yourself a Scheme in 48 Hours
• Parallel and Concurrent Programming in Haskell

mzero

#!/bin/sh

inPreprocessorMode () {
    hasE=0
    hasU=0
    hasT=0
    for arg in "$@"
    do
        if [ 'x-E' = "x$arg" ];             then hasE=1; fi
        if [ 'x-undef' = "x$arg" ];         then hasU=1; fi