Add console presentation on ruby 2.4 new features

2017-01-ruby-2.4/23/01.rb

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+p !!/foo/.match("foo")
+p !!"foo".match(/foo/)
+p !!:foo.match(/foo/)

2017-01-ruby-2.4/23/02.rb

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+Thread.new do
+  begin
+    raise 'foo'
+  rescue Exception => e
+    puts "#{Thread.current} terminated with exception:"
+    puts "#{e.backtrace.first}: #{e.message} (#{e.class})"
+  end
+end
+sleep 0.01
+

2017-01-ruby-2.4/23/03.rb

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+require 'irb'
+IRB.setup(eval("__FILE__"))
+irb = IRB::Irb.new(IRB::WorkSpace.new(binding))
+IRB.conf[:MAIN_CONTEXT] = irb.context
+irb.eval_input

2017-01-ruby-2.4/23/04.rb

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+p Integer.equal?(Integer)
+p Integer.equal?(Integer)

2017-01-ruby-2.4/23/05.rb

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+# No equivalent 
+s = "\u00EB\u00C4\u00D6"
+p s
+p s.upcase
+p s.downcase
+p s.swapcase
+p s.capitalize

2017-01-ruby-2.4/23/06.rb

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+if (a, b = [1, 2]; [1,2])
+  p a
+  p b
+end
+unless (a, b = nil; nil)
+  p a
+  p b
+end

2017-01-ruby-2.4/23/07.rb

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+module Foo
+  refine String do
+    def a; 1; end
+  end
+end
+
+using Foo
+meth = :a
+eval <<END
+using Foo
+p 'a'.#{meth}
+p 'ab'.each_char.map{|s| s.#{meth}}
+END

2017-01-ruby-2.4/23/08.rb

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+puts ((raise rescue 1))
+begin
+  eval('puts(raise rescue 1)')
+rescue SyntaxError
+  puts "Still Bad"
+end

2017-01-ruby-2.4/23/09.rb

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+p 1
+if false
+p 2
+end

2017-01-ruby-2.4/23/10.rb

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+# No equivalent
+o = Object.new
+def o.foo; 1 end
+o.freeze
+
+begin
+x = o.clone
+def x.bar; foo + 2 end
+p x.bar
+rescue
+  p $!
+end
+
+begin
+x = o.dup
+def x.bar; foo + 2 end
+x.freeze
+p x.bar
+rescue
+  p $!
+end
+

2017-01-ruby-2.4/23/11.rb

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+# No equivalent
+$VERBOSE = true
+instance_variable_get(:@foo)
+$a

2017-01-ruby-2.4/23/12.rb

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+p (1...100).inject(0, :+)
+p (1...100).to_a.inject(0, :+)

2017-01-ruby-2.4/23/13.rb

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+s = StringIO.new <<END
+a
+b
+a
+c
+END
+p s.each_line.to_a.uniq

2017-01-ruby-2.4/23/14.rb

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+p File.zero?(__FILE__)
+p Dir.new(__dir__).entries.length == 2
+require 'pathname'
+p File.zero?(Pathname.new(__FILE__).to_s)

2017-01-ruby-2.4/23/15.rb

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+m = 'food'.match(/(?<a>.)(?<b>..)(?<c>.)/)
+p m.names.inject({}){|a, n| a[n] = m[n]; a}
+p [:a, :b, :c].map{|c| m[c]}

2017-01-ruby-2.4/23/16.rb

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+p 1234.to_s.split(//).reverse.map(&:to_i)

2017-01-ruby-2.4/23/17.rb

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+f = 12.35678
+p((f*(10**1)).ceil/(10.0**1))
+p((f*(10**2)).floor/(10.0**2))
+p((f*(10**3)).round/(10.0**3))
+p((f*(10**4)).truncate/(10.0**4))

2017-01-ruby-2.4/23/18.rb

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+f = 12.5
+p ((f.round - f == 0.5) ? (f.round.odd? ? f.round - 1 : f.round) : f.round)
+p f.round
+p ((f.round - f == 0.5) ? f.round - 1 : f.round)

2017-01-ruby-2.4/23/19.rb

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+p :foo.to_s.match(/foo/)

2017-01-ruby-2.4/23/20.rb

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+p [3].concat([1]).concat([2])
+p "foo".concat("bar").concat("baz")
+p "foo".prepend("baz").prepend("bar")

2017-01-ruby-2.4/23/21.rb

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+p 1 < 3 ? 3 : (1 > 5 ? 5 : 1)
+p 4 < 3 ? 3 : (4 > 5 ? 5 : 4)
+p 7 < 3 ? 3 : (7 > 5 ? 5 : 7)

2017-01-ruby-2.4/23/22.rb

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+p({a: 1, b: nil}.inject({}){|a, (k,v)| a[k] = v unless v.nil?; a})

2017-01-ruby-2.4/23/23.rb

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+p({a: 1, b: nil}.inject({}){|a, (k,v)| a[k] = !v; a})

2017-01-ruby-2.4/23/24.rb

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+File.open('runner.rb').each_line{|l| p l.chomp; break}
+StringIO.new("a\nb\n").each_line{|l| p l.chomp}
+"a\nb\n".each_line{|l| p l.chomp}
+p "a\nb\n".lines.map(&:chomp)

2017-01-ruby-2.4/23/25.rb

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+# No equivalent
+module Foo
+  refine Enumerable do
+    def a; 1 end
+  end
+end
+
+using Foo
+p [].a

2017-01-ruby-2.4/23/26.rb

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+# No equivalent
+module Foo
+  refine String do
+    def a; 1 end
+  end
+end
+
+p Module.used_modules
+using Foo
+p Module.used_modules

2017-01-ruby-2.4/23/27.rb

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+p "\x10\x00".unpack('s').first

2017-01-ruby-2.4/23/28.rb

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+s = ''.b
+s.replace([1].pack('s'))
+p s

2017-01-ruby-2.4/23/29.rb

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+p ((x = 'foo'.casecmp('Foo')).is_a?(Integer) ? x.zero? : x)
+p ((x = :foo.casecmp(:Bar)).is_a?(Integer) ? x.zero? : x)

2017-01-ruby-2.4/23/30.rb

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+require 'net/http'
+require 'uri'
+url = URI('http://localhost/')
+Net::HTTP.start(url.hostname, url.port) do |http|
+  http.post(url.path, "q" => "ruby")
+end

2017-01-ruby-2.4/23/31.rb

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+# No built-in equivalent
+require 'double_bag_ftps'
+ftp = DoubleBagFTPS.new
+ftp.connect('localhost')

2017-01-ruby-2.4/23/32.rb

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+p TRUE
+p FALSE
+p NIL

2017-01-ruby-2.4/23/33.rb

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+require 'logger'
+logger = Logger.new($stderr)
+logger.level = :info
+logger.progname = 'L2'
+logger.info 'foo'

2017-01-ruby-2.4/23/34.rb

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+require 'optparse'
+h = {}
+OptionParser.new do |o|
+  o.on "-f", "--foo=HOST" do |v|
+    h[:foo] = v
+  end
+  o.on "-b", "--bar=PORT", Integer do |v|
+    h[:bar] = v
+  end
+  o.on "-B", "--baz" do
+    h[:baz] = true
+  end
+end.parse(%w'-f FOO --bar 3 -B')
+p h

2017-01-ruby-2.4/23/35.rb

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+p (10.0**400) < Float::MIN ? -1 : ((10.0**400) > Float::MAX ? 1: true)
+p -(10.0**400) < Float::MIN ? -1 : (-(10.0**400) > Float::MAX ? 1: true)
+p 1.0 < Float::MIN ? -1 : (1.0 > Float::MAX ? 1: true)

2017-01-ruby-2.4/23/36.rb

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+# No equivalent
+p String.new

2017-01-ruby-2.4/24/01.rb

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+p /foo/.match?("foo")
+p "foo".match?(/foo/)
+p :foo.match?(/foo/)

2017-01-ruby-2.4/24/02.rb

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+Thread.new do
+  Thread.current.report_on_exception = true
+  raise  'foo'
+end
+sleep 0.01

2017-01-ruby-2.4/24/03.rb

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+require 'irb'
+binding.irb

2017-01-ruby-2.4/24/04.rb

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+p Fixnum.equal?(Integer)
+p Bignum.equal?(Integer)

2017-01-ruby-2.4/24/05.rb

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+s = "\u00EB\u00C4\u00D6"
+p s
+p s.upcase
+p s.downcase
+p s.swapcase
+p s.capitalize

2017-01-ruby-2.4/24/06.rb

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+if (a, b = [1, 2])
+  p a
+  p b
+end
+unless (a, b = nil)
+  p a
+  p b
+end

2017-01-ruby-2.4/24/07.rb

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+module Foo
+  refine String do
+    def a; 1; end
+  end
+end
+
+using Foo
+meth = :a
+p 'a'.send(meth)
+p 'ab'.each_char.map(&meth)

2017-01-ruby-2.4/24/08.rb

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+puts (raise rescue 1)
+begin
+  eval('puts(raise rescue 1)')
+rescue SyntaxError
+  puts "Still Bad"
+end

2017-01-ruby-2.4/24/09.rb

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+p 1
+return
+p 2

2017-01-ruby-2.4/24/10.rb

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+o = Object.new
+def o.foo; 1 end
+o.freeze
+x = o.clone(freeze: false)
+def x.bar; foo + 2 end
+x.freeze
+p x.bar

2017-01-ruby-2.4/24/11.rb

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+$VERBOSE = true
+def Warning.warn(s)
+  puts "WARNING: #{s}" unless s =~ /instance variable @.+ not initialized/
+end
+instance_variable_get(:@foo)
+$a

2017-01-ruby-2.4/24/12.rb

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+p (1...100).sum
+p (1...100).to_a.sum

2017-01-ruby-2.4/24/13.rb

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+s = StringIO.new <<END
+a
+b
+a
+c
+END
+p s.each_line.uniq

2017-01-ruby-2.4/24/14.rb

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+p File.empty?(__FILE__)
+p Dir.empty?(__dir__)
+require 'pathname'
+p Pathname.new(__FILE__).empty?

2017-01-ruby-2.4/24/15.rb

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+m = 'food'.match(/(?<a>.)(?<b>..)(?<c>.)/)
+p m.named_captures
+p m.values_at(:a, :b, :c)

2017-01-ruby-2.4/24/16.rb

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+p 1234.digits

2017-01-ruby-2.4/24/17.rb

@@ -0,0 +1,5 @@
+f = 12.35678
+p f.ceil(1)
+p f.floor(2)
+p f.round(3)
+p f.truncate(4)

2017-01-ruby-2.4/24/18.rb

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+f = 12.5
+p f.round(half: :even)
+p f.round(half: :up)
+p f.round(half: :down)

2017-01-ruby-2.4/24/19.rb

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+p :foo.match(/foo/)

2017-01-ruby-2.4/24/20.rb

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+p [3].concat([1], [2])
+p "foo".concat("bar", "baz")
+p "foo".prepend("bar", "baz")

2017-01-ruby-2.4/24/21.rb

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+p 1.clamp(3, 5)
+p 4.clamp(3, 5)
+p 7.clamp(3, 5)

2017-01-ruby-2.4/24/22.rb

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+p({a: 1, b: nil}.compact)

2017-01-ruby-2.4/24/23.rb

@@ -0,0 +1 @@
+p({a: 1, b: nil}.transform_values{|v| !v})

2017-01-ruby-2.4/24/24.rb

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+File.open('runner.rb').each_line(chomp: true){|l| p l; break}
+StringIO.new("a\nb\n").each_line(chomp: true){|l| p l}
+"a\nb\n".each_line(chomp: true){|l| p l}
+p "a\nb\n".lines(chomp: true)

2017-01-ruby-2.4/24/25.rb

@@ -0,0 +1,8 @@
+module Foo
+  refine Enumerable do
+    def a; 1 end
+  end
+end
+
+using Foo
+p [].a

2017-01-ruby-2.4/24/26.rb

@@ -0,0 +1,9 @@
+module Foo
+  refine String do
+    def a; 1 end
+  end
+end
+
+p Module.used_modules
+using Foo
+p Module.used_modules

2017-01-ruby-2.4/24/27.rb

@@ -0,0 +1 @@
+p "\x10\x00".unpack1('s')

2017-01-ruby-2.4/24/28.rb

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+s = ''.b
+[1].pack('s', :buffer=>s)
+p s

2017-01-ruby-2.4/24/29.rb

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+p 'foo'.casecmp?('Foo')
+p :foo.casecmp?(:Bar)

2017-01-ruby-2.4/24/30.rb

@@ -0,0 +1,3 @@
+require 'net/http'
+require 'uri'
+Net::HTTP.post(URI('http://localhost/'), {"q" => "ruby"})

2017-01-ruby-2.4/24/31.rb

@@ -0,0 +1,2 @@
+require 'net/ftp'
+ftp = Net::FTP.new('localhost', :ssl=>true)

2017-01-ruby-2.4/24/32.rb

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+p TRUE
+p FALSE
+p NIL

2017-01-ruby-2.4/24/33.rb

@@ -0,0 +1,3 @@
+require 'logger'
+logger = Logger.new($stderr, level: :info, progname: "L2")
+logger.info 'foo'

2017-01-ruby-2.4/24/34.rb

@@ -0,0 +1,8 @@
+require 'optparse'
+h = {}
+OptionParser.new do |o|
+  o.on "-f", "--foo=HOST"
+  o.on "-b", "--bar=PORT", Integer
+  o.on "-B", "--baz"
+end.parse(%w'-f FOO --bar 3 -B', :into=>h)
+p h

2017-01-ruby-2.4/24/35.rb

@@ -0,0 +1,3 @@
+p (10.0**400).infinite?
+p (-(10.0**400)).infinite?
+p (1.0).finite?

2017-01-ruby-2.4/24/36.rb

@@ -0,0 +1 @@
+p String.new(:capacity=>1 << 30)