Ruby 2.0 upcoming changes

A very brief look at ruby 2.0 upcoming changes

Transcript

1. Ruby 2.0 Upcoming Changes Monday, 21 January 13
2. List of things • Refinements • Keyword arguments • Module#prepend • DTrace Support • TracePoint Monday, 21 January 13
3. Refinements Class extension without global namespace pollution Monday, 21 January 13
4. Monkey patching class Fixnum def hours_ago Time.now - self*3600 end end 10.hours_ago Monday, 21 January 13
5. New way module FixnumExtras refine Fixnum do def hours_ago Time.now - self*3600 end end end > 10.hours_ago Undefined method > using FixnumExtras > 10.hours_ago Monday, 21 January 13
6. Another use case? module FixnumExtras refine Fixnum do def hours_ago Time.now - self*3600 end end end class Foo using FixnumExtras end class Bar < Foo def hello 10.hours_ago end end a = Bar.new() a.hello() Monday, 21 January 13
7. Wrong module FixnumExtras refine Fixnum do def hours_ago Time.now - self*3600 end end end class Foo using FixnumExtras end class Bar < Foo def hello 10.hours_ago end end a = Bar.new() a.hello() Monday, 21 January 13
8. Mind bender • using can only be called on main object. module StringExtras refine String do def wow puts "Called wow" end end end using StringExtras class Foo def hello "hello".wow() end end a = Foo.new() a.hello Monday, 21 January 13
9. More mind benders • It is limited to file scope • scope begins where using is called and ends at the end of file. • It is confusing as hell and may change in future. Monday, 21 January 13
10. More docs http://blog.headius.com/2012/11/refining-ruby.html http://timelessrepo.com/refinements-in-ruby https://bugs.ruby-lang.org/projects/ruby-trunk/wiki/ RefinementsSpec Monday, 21 January 13
11. Keyword arguments def link_to(url, css_klass: 'foo', css_id: 'foo') %Q{<a href="#{url}" class=#{css_klass} id=#{css_id} />} end link_to("http://www.google.com", css_klass: "foo", css_id: "bar") Monday, 21 January 13
12. How different from Hash? Monday, 21 January 13
13. def link_to(url, options = {} ) css_klass = options[:css_klass] css_id = options[:css_id] %Q{<a href="#{url}" class=#{css_klass} id=#{css_id} />} end link_to("http://www.google.com", css_klass: "foo", css_id: "bar") def link_to(url, css_klass: 'foo', css_id: 'foo') %Q{<a href="#{url}" class=#{css_klass} id=#{css_id} />} end link_to("http://www.google.com", css_klass: "foo", css_id: "bar") Monday, 21 January 13
14. Module#prepend The most awesomest thing Monday, 21 January 13
15. Pains it solves • alias_method_chain • remove_method and redefine the method • always define API methods of your class in modules. Monday, 21 January 13
16. Ruby techniques by example http://jeremyevans-pres.heroku.com/ rubymw2010_presentation/index.html Monday, 21 January 13
17. Usage Monday, 21 January 13
18. Usage class Foo def hello puts "hello from foo" end end Monday, 21 January 13
19. Usage class Foo def hello puts "hello from foo" end end class Bar < Foo def hello puts "hello from bar" end end Monday, 21 January 13
20. Usage class Foo def hello puts "hello from foo" end end class Bar < Foo def hello puts "hello from bar" end end class Foo def hello puts "overridden definition of hello" end end Monday, 21 January 13
21. Usage class Foo def hello puts "hello from foo" end end class Bar < Foo def hello puts "hello from bar" end end class Foo def hello puts "overridden definition of hello" end end module FooExtensions def self.included(base) base.undef_method :hello end def hello puts "Hello from Foo extensions" end end Foo.send(:include,FooExtensions) Monday, 21 January 13
22. New way class Foo def hello puts "hello from foo" end end module FooExtensions def hello puts "Hello from Foo extensions" end end Foo.send(:prepend, FooExtensions) a = Foo.new() a.hello() Monday, 21 January 13
23. TracePoint Nicer set_trace_func Monday, 21 January 13
24. TracePoint trace = TracePoint.new(:call) do |tp| p [tp.lineno, tp.defined_class, tp.method_id, tp.event] end trace.enable MoreComplex.new().start() Monday, 21 January 13
25. Useful for CPU Profiling Monday, 21 January 13
26. DTrace hooks Monday, 21 January 13