abp

Inheritance is a key concept in most object-oriented languages, but applying it skillfully can be challenging in practice. Back in 1989, M. Sakkinen wrote a paper called Disciplined inheritance that addresses these problems and offers some useful criteria for working around them. Despite being more than two decades old, this paper is extremely relevant to the modern Ruby programmer.

Sakkinen's central point seems to be that most traditional uses of inheritance lead to poor encapsulation, bloated object contracts, and accidental namespace collisions. He provides two patterns for disciplined inheritance and suggests that by normalizing the way that we model things, we can apply these two patterns to a very wide range of scenarios. He goes on to show that code that conforms to these design rules can easily be modeled as ordinary object composition, exposing a solid alternative to tradi

Initial thoughts on Datomic

Rich Hickey (of [Clojure][1] fame) has released a cloud-based database called [Datomic][2] that has some interesting properties.

Datomic is an log of assertions and retractions of "facts", much as a DVCS like [Git][3] is a log of code diffs. The state of the database at any one time is the sum of all the assertions and retractions up to that date.

	;; I could have used a closed dispatch (aka cond) but you may find this version more enjoyable
	;; the spec format is the one provided by BG

	(defprotocol Selector
	(-select [s m]))

	(defn select [m selectors-coll]
	(reduce conj {} (map #(-select % m) selectors-coll)))

	(extend-protocol Selector

	(ns datomic-play.core
	(:use [datomic.api :only [db q] :as d])
	(:require [clojure.core.logic :as l]
	[clojure.pprint :as pp]))

	(def uri "datomic:dev://localhost:4334/hello")

	(defprotocol IUnifyWithDatum
	(unify-with-datum [u v s]))

	;; Datomic example code
	(use '[datomic.api :only (db q) :as d])

	;; ?answer binds a scalar
	(q '[:find ?answer :in ?answer]
	42)

	;; of course you can bind more than one of anything
	(q '[:find ?last ?first :in ?last ?first]
	"Doe" "John")

	// ©2012 Viktor Klang
	// 6,016 bytes jarred.
	package java.klang;
	import java.util.concurrent.*;
	import java.util.concurrent.atomic.AtomicInteger;
	public class Actor {
	public static interface Fun<T, R> { public R apply(T t); }
	public static interface Effect extends Fun<Behavior, Behavior> { };
	public static interface Behavior extends Fun<Object, Effect> { };
	public static interface Address { Address tell(Object msg); };

	(extend-type js/RegExp
	cljs.core.IFn
	(-invoke ([this s] (re-matches this s))))

	(#"foo.*" "foobar") ;=> "foobar"
	(#"zoo.*" "foobar") ;=> nil

	(filter #".foo." ["foobar" "goobar" "foobaz"]) ;=> ("foobar" "foobaz")

	; very basic example of driving a listbox with binding in Seesaw
	(use 'seesaw.core)
	(require '[seesaw.bind :as b])

	; create a text box and a listbox next to each other
	(defn make-ui []
	(frame
	:size [400 :by 400]
	:content (left-right-split
	(scrollable (text :id :text :multi-line? true))

	#!/usr/bin/env ruby

	# giftube – Generates an animated gif from a YouTube url.
	#
	# Usage:
	#
	# giftube [youtube url] [minute:second] [duration]
	#
	# ex.
	#

	; Invoke a macro like a function - if you dare.
	; ______
	; .-" "-.
	; / \
	; _ \| \| _
	; ( \ \|, .-. .-. ,\| / )
	; > "=._ \| )(__/ \__)( \| _.=" <
	; (_/"=._"=._ \|/ /\ \\| _.="_.="\_)
	; "=._ (_ ^^ _)"_.="
	; "=\__\|IIIIII\|__/="