Pedro Alvarado visdesarrollo2

My issues with Modules

In researching topics for RailsCasts I often read code in Rails and other gems. This is a great exercise to do. Not only will you pick up some coding tips, but it can help you better understand what makes code readable.

A common practice to organize code in gems is to divide it into modules. When this is done extensively I find it becomes very difficult to read. Before I explain further, a quick detour on instance_eval.

You can find instance_eval used in many DSLs: from routes to state machines. Here's an example from Thinking Sphinx.

class Article &lt; ActiveRecord::Base

	#! /usr/bin/env ruby
	# usage:
	# $ das_download.rb email password [download_directory]

	require 'mechanize'
	# gem 'mechanize-progressbar'

	email = ARGV[0] or raise('Please provide the email address for your account')
	password = ARGV[1] or raise('Please provide the password for your account')
	path = ARGV[2] \|\| './'

	Installar Imagemagick
	sudo apt-get install imagemagick libmagickwand-dev

	luego
	gem install rmagick

	// layout file

	<body>
	<div class="container">

	<%= flash_messages %>

	<%= yield %>
	</div><!-- /container -->
	</body>

	<% flash.each do \|type, message\| %>
	<div class="alert <%= bootstrap_class_for(type) %> fade in">
	<button class="close" data-dismiss="alert">×</button>
	<%= message %>
	</div>
	<% end %>

	# autoload concerns
	module YourApp
	class Application < Rails::Application
	config.autoload_paths += %W(
	#{config.root}/app/controllers/concerns
	#{config.root}/app/models/concerns
	)
	end
	end

	# requires BSD sed
	namespace :whitespace do
	desc 'Removes trailing whitespace'
	task :cleanup do
	sh %{for f in `find . -type f \| grep -v .git \| grep -v ./vendor \| grep -v ./tmp \| egrep ".(rb\|js\|haml\|html\|css\|sass)"`;
	do sed -i '' 's/ *$//g' "$f";
	done}, {:verbose => false}
	puts "Task cleanup done"
	end