(Some) differences between ruby versions.

ruby_differences.rb

#!/bin/env ruby
# encoding: utf-8

# Differences between Ruby versions

code = case ARGV[0]

	when "1"

		puts "- Local block variables"
		<<-CODE
			i = 10
			1.upto(5) do |i|
			  puts i
			end
			puts \"i is \#{i}\"
		CODE

	when "2"

		puts "- Hash changes"
		<<-CODE
			hash = { 'dog' => 'bark', 'cat' => 'meow', 'bird' => 'tweet' }
			puts hash.keys.inspect
			puts hash.to_s
		CODE

	when "3"

		puts "- String changes"
		<<-CODE
			puts "STRING"[0]
			puts "eñe".size
		CODE

	when "4"
		puts "- Syntax changes"
		[
		"
		    my_proc = -> x { puts x + 1 }
		    my_proc.call(10)
		",
		"
			my_proc = proc { |x| puts x + 1 }
			my_proc.(10)
		",
		"
			hash = { foo: 'bar', baz: 'quux' }
			puts hash
		"
		]
	when "5"
		puts "- Method changes"
		[
		"
			def some_method(required, *optional, config)
				puts \"Required: \#{required}\"
				puts \"Optional: \#{optional}\"
				puts \"Config: \#{config}\"
			end
			some_method(1, 2, 3, 4, :option_1 => 'x', :option_2 => 'y')
		",
		"
			def some_method(first = \"first\", second)
				puts [first, second].inspect
			end
			some_method(10)
		"
		]
end

code = [code] if code.is_a?(String)
code.each do |c|
	puts c

	$stdin.gets

	begin
		eval c
	rescue SyntaxError => e
		puts e
	end

	puts "----------"
end