James Edward Gray II JEG2

How Should We Use Struct?

The Choice

It's common in Ruby to see some code setup a Struct like this:

class Specialized < Struct.new(:whatever)
  # ... define custom methods here...
end

I've been in multiple discussions lately about the problems with subclassing Ruby's base types.

The main problem is that Ruby sometimes takes shortcuts with the base types, for performance reasons. This can cause them to behave odd. For example, have a look at this subclass:

class MyString < String
  def initialize(*)
    super
    puts "Building MyString:  #{inspect}"
  end

I have a problem that pretty much boils down to this:

a = [1, 2, 3]
b = [1.1, 2.2, 3.3]

# BEGIN GROSS SOLUTION:  avert your eyes!
results = [ ]
a.each do |i|
 b.each do |j|

	<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
	"http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
	<html xmlns="http://www.w3.org/1999/xhtml">
	<head>
	<title>Ruby Quiz - Dice Roller (#61)</title>
	<link rel="stylesheet" type="text/css" href="quiz.css" />
	<link rel="stylesheet" type="text/css" href="print.css" media="print" />
	</head><body>
	<div id="page">
	<div id="header"><span class="ruby">Ruby</span> <span class="quiz">Quiz</span></div>

	module Plugin
	def some_method
	puts "Plugin"
	super
	end
	end

	class A
	def some_method
	puts "A"

	class RequiredArgument
	def initialize(one, keyword: false)
	p [one, keyword]
	end
	end

	RequiredArgument.new(Hash.new)

	# ruby 2.0.0p195 (2013-05-14 revision 40734) [x86_64-darwin12.3.0]
	# bug.rb:2:in `initialize': wrong number of arguments (0 for 1) (ArgumentError)

	~/Desktop [ruby 2.0.0p247]$ cat dont_close_my_logger.rb
	require "logger"

	log = ARGV.shift or abort "USAGE: #{$PROGRAM_NAME} LOG"
	logger = Logger.new(log)

	threads = [ ]
	threads << Thread.new do
	logger.info "Thread one started. Sleeping a bit to make sure thread two is going..."
	sleep 1

	headers = nil
	File.foreach(path) do \|line\|
	fields = line.split(“\|”)
	if headers
	row = headers.zip(fields)
	# …
	else
	headers = fields
	end
	end

	(set-face-attribute 'window-number-face nil :background "#2a2a2a")
	(set-face-attribute 'window-number-face nil :foreground "red")

	use std::fmt;
	use std::os;

	struct Stack {
	numbers: Vec<f64>
	}
	impl Stack {
	fn new() -> Stack {
	Stack{numbers: vec![]}
	}