njonsson

[This is [a DZone Snippet I created in August 2007][dzone-snippet]. DZone Snippets is now a defunct site, so I’m reposting it here.]

Dependency injection in Ruby is as easy as falling off a log. As [Jamis Buck has pointed out][jamis-buck-net-ssh-revisited], DI is a good thing, but DI frameworks for Ruby are overkill. The language makes them unnecessary.

Here's how to enhance [Module#attr_reader][ruby-module-attr-reader] and [#attr_accessor][ruby-module-attr-accessor] so that they can receive an options hash for specifying the default value of an attribute.

module AttrWithDefaultExtension
  
  module ClassMethods

njonsson

Keybase proof

I hereby claim:

• I am njonsson on github.
• I am njonsson (https://keybase.io/njonsson) on keybase.
• I have a public key whose fingerprint is 546E EA0C B2D1 AFC7 D08B B11C 27D3 E4D0 BF33 68B4

To claim this, I am signing this object:

njonsson

using System;
using System.Diagnostics;

/// <summary>
/// Serves as a wrapper around objects that require disposal but that do not
/// implement <see cref="System.IDisposable"/>.
/// </summary>
/// <typeparam name="T">The type of <see cref="Object"/></typeparam>
public abstract class DisposerBase<T> : IDisposable
{

njonsson

// (Do this up front somewhere else.)
var closeMethod = typeof(OpenNETCF.Phone.Sim.Sim).GetMethod("Close");

// (Do this many times.)
using (var disposer = new Disposer<OpenNETCF.Phone.Sim.Sim>(OpenNETCF.Phone.Sim.Sim(), closeMethod))
{
    // Use the 'disposer.Object' property ...
}

njonsson

using (var disposer = new Disposer<OpenNETCF.Phone.Sim.Sim>(new OpenNETCF.Phone.Sim.Sim(), "Close"))
{
    // Use the 'disposer.Object' property ...
}

njonsson

var sim = new OpenNETCF.Phone.Sim.Sim();
try
{
    // Use the 'sim' variable ...
}
finally
{
    sim.Close();
}

njonsson

// Unfortunately, this isn't possible.
using (var sim = new OpenNETCF.Phone.Sim.Sim())
{
    // Use the 'sim' variable ...
}

njonsson

#! /usr/bin/env ruby

def pluralize(word, count=2, plural_word=nil)
  plural_word ||= "#{word}s"
  "#{count} #{(count == 1) ? word : plural_word}"
end

unless (ARGV.length == 1) &&
       (good_revision = system("git log -1 #{ARGV.first} 2>/dev/null"))
  puts "Unknown revision '#{ARGV.first}'" unless good_revision

njonsson

source 'http://rubygems.org'

gem 'rake'

group :development do
  gem 'autotest'
  gem 'autotest-fsevent'
  gem 'ruby-debug'
end

njonsson

require 'sinatra'

get '/all-good' do
  [200, [['Set-Cookie', 'foo=bar; baz']], 'Hello World!']
end

get '/huh' do
  [404, 'What?']
end