#omotesandorb

2. 🎉

3. require 'rubygems'
require 'open-uri
specs = Marshal.load(Gem.gunzip(File.read("./latest_specs.4.8.gz")))
total = specs.length
specs.each do |gem_name, gem_version, _|
begin
compressed = open("https://rubygems.org/quick/Marshal.4.8/#{gem_name}-#{gem_version}.gemspec.rz").read
inflated = Gem.inflate(compressed)
spec = Marshal.load(inflated)
ruby1_8 = Gem::Version.new("1.8.7")
ruby1_9 = Gem::Version.new("1.9.3")
ruby2_0 = Gem::Version.new("2.0.0")
ruby2_1 = Gem::Version.new("2.1.0")
ruby2_2 = Gem::Version.new("2.2.0")
ruby2_3 = Gem::Version.new("2.3.0")
ruby2_4 = Gem::Version.new("2.4.0")
ruby2_5 = Gem::Version.new("2.5.0")
ruby2_5_1 = Gem::Version.new("2.5.1")
ruby2_5_2 = Gem::Version.new("2.5.2")
ruby2_5_3 = Gem::Version.new("2.5.3")
ruby2_6 = Gem::Version.new("2.6.0")
old_versions = [ruby1_8, ruby1_9, ruby2_0, ruby2_1,
ruby2_2, ruby2_3, ruby2_4, ruby2_5,
ruby2_5_1, ruby2_5_2, ruby2_5_3]
required = spec.required_ruby_version
if old_versions.all?{|v| !required.satisfied_by?(v) } && required.satisfied_by?(ruby2_6)
puts "#{gem_name}-#{gem_version}"
end
rescue => e
puts "#{gem_name}: #{e.message}"
end
end

11. require 'function-composite'
using Function::Composite
p %w{72 101 108 108 111}.map(&:to_i >> :chr) #=> ["H", "e", "l", "l", "o"]
p %w{72 101 108 108 111}.map(&proc { |s| s.to_i } >> :chr) #=> ["H", "e", "l", "l", "o"]
h = { Alice: 30, Bob: 60, Cris: 90 }
p %w{Alice Bob Cris}.map(&(:to_sym >> h)) #=> [30, 60, 90]

14. 😳

16. 😅