catch in Ruby is meant to jump out of deeply nested code. In Java e.g. it is possible to achieve the same with Java's try-catch meant for handling exceptions, it is however considered poor solution and is also very inefficient. In Ruby for handling exceptions we have begin-raise-rescue and I assume it is also to expensive to use it for other tasks.
Is Ruby's catch-throw really a more efficient solution then begin-raise-rescue or are there any other reasons to use it to break nested blocks instead of begin-raise-rescue?
In addition to being the "correct" way to get out of control structures, catch-throw is also significantly faster(10 times as fast in my testing). Check out this gist for my code and results.
Josh's answer is correct. I want to add more information about catch-throw and raise-rescue.
catch-throw is used for flow control whereas raise-rescue is used for exception/error handling. The different is: backtrace is not needed for catch-throw (flow control). Trust me, the main reason causes raise-rescue runs slow than catch-throw 10 times in Josh's gist is raise-rescue takes a lot time to create backtrace object.
If you want to raise without backtrace, use syntax:
raise <type>, <message>, <backtrace>
Checkout my gist. raise without backtrace is much faster than raise with backtrace.
April 2016 Update:
I've updated my gist:
- Fixed "break" test
- Added benchmark tests results for newer ruby version 2.1.8, 2.2.4, 2.3.0
来源：https://stackoverflow.com/questions/13484004/ruby-catch-throw-and-efficiency