From: Yong Li <gilbertly@...>
Date: 2011-12-16T14:17:36+09:00
Subject: [ruby-core:41690] Re: Documentation of the language itself (syntax, meanings, etc)

>
> Still, I don't like using exceptions as a control flow mechanism for entirely un-exceptional situations.
>
I strongly agree with this, even though I have myself met a similar
situation in the past:

def action
  check_input

  return if handle_special_input1_and_return  # This is valid input
and return logic, so exception is inappropriate

  return if handle_special_input2_and_return

  handle_common_cases
end

I did not want to inline "handle_special_inputx_and_return" because it
would make the action method too long and blur the main logic.
However, extracting them to private methods would make the code more
verbose as I cannot return "action" from within
"handle_special_input_and_return", and this forces me to return a
value from "handle_special_input_and_return" and check them in
"action".

I was also trying hard to get around this, but finally settled on this
for the following reasons:
* The only way to break out multiple levels of code (nested methods or
loops or both) is to use a "go-to" like operation, which allows you to
jump to anywhere in you code. Exceptions can be used for this purpose.
But again, this is very bad.
* go-to operations are rarely good to use
* the purpose and condition of return is clear and explicit, which
reduces confusions for other people

Maybe I could re-design my code to avoid such situations in the first
place, but that would be a completely different story.

I would be very glad to hear a more succinct solution and throw my
silly argument under the bus :-D