Mangling Ruby with TracePoint

@markbates

http://mo.markbates.com

RUBYCONF13 http://www.metacasts.tv

Mangling Ruby with TracePoint

TracePoint

trace = TracePoint.new(:raise) do |tp| p [tp.lineno, tp.event, tp.raised_exception] end #=> #<TracePoint:0x007f786a452448> !trace.enable #=> #<TracePoint:0x007f786a452448> !0 / 0 #=> [5, :raise, #<ZeroDivisionError: divided by 0>]

Events

TracePoint.new(:class) TracePoint.new(:end)

TracePoint.new(:call) TracePoint.new(:return) TracePoint.new(:c_call) TracePoint.new(:c_return)

TracePoint.new(:raise)

TracePoint.new(:b_call) TracePoint.new(:b_return)

TracePoint.new(:thread_begin) TracePoint.new(:thread_end)

Demo

Method Call Collector

TracePoint: disable 1 enable 1 !Object: puts 1 at_exit 1 !Class: new 1 method_added 1 inherited 1 !Foo: bar 1 initialize 1 !IO: write 2 puts 1 !Symbol: to_proc 1 !Array: map 1

------------- Totals: Class 3 IO 3 Object 2 TracePoint 2 Foo 2 Symbol 1 Array 1 !! Total Method Calls: 14

Total Method Calls: 122538

Class 25888 Rails::Initializable::Initializer 16502 Symbol 14136 Module 12727 String 11379 Array 6080 Hash 4479 Fixnum 3108 Object 2499 ActionDispatch::Journey::Visitors::Each 2276 File 1888 Rails::Paths::Path 1655 Regexp 1190 ThreadSafe::Cache 1026

HelloController: class 13 process_action 7 lookup_context 4 initialize 4 instance_variable_defined? 4 method_for_action 3 respond_to? 3 render 3 _normalize_options 3 render_to_body 3 _process_options 3 block_given? 2 dispatch 2 view_renderer 2 _render_template 2 process 2 append_info_to_payload 2 _prefixes 2 response_body= 2 config 2 instance_variable_get 2 _normalize_args 2 cleanup_view_runtime 2

Demo

jRuby

Abstract Interfaces IN RUBY!

Please Don’t!Actually Do This!

interface Bicycle { void changeGear(int newValue); void speedUp(int increment); void applyBrakes(int decrement); } !public class ACMEBicycle implements Bicycle { public void changeGear(int newValue) { // do some work here } public void speedUp(int increment) { // do some work here } public void applyBrakes(int decrement) { // do some work here } }

module ApiInterface include AbstractInterface abstract_method :get, :put end !class HttpLibrary include ApiInterface end

module ApiInterface include AbstractInterface abstract_method :get, :put end !class HttpLibrary include ApiInterface end

module ApiInterface include AbstractInterface abstract_method :get, :put end !class HttpLibrary include ApiInterface def get end def put end end

module ApiInterface include AbstractInterface abstract_method :get, :put end !class HttpLibrary include ApiInterface end

@markbates http://www.metacasts.tv