From: Matthew Kerwin <matthew@...>
Date: 2013-07-05T23:32:23+09:00
Subject: Re: How do I rescue a program exception in an at_exit block?

It's a pure, unadulterated hack, but you can "exec" something at the
end of your at_exit block, to replace the ruby process with something
else, thus avoiding the final error report.

  at_exit do
    error = $!
    if error
      #...
    end
    exec 'echo -n ""'
  end
  raise 'badness'

On 6 July 2013 00:08, Josh Cheek <josh.cheek@gmail.com> wrote:
> I was thinking about how bad I am at reading error messages, and realized it
> could be useful to catch the exception and write it in a way that was easier
> for me to find the relevant information. So, came up with this proof of
> concept:
>
> at_exit do
>   error = $!
>   if error
>     pink, normal, red, green = "\e[35m", "\e[0m", "\e[31m", "\e[32m"
>
>     puts
>     puts "#{pink}#{error.class}"
>     puts "#{red}#{error.message}#{normal}"
>     puts
>     puts error.backtrace.map { |line|
>       line.sub(%r([^/:]*(?=:)))    { |match| "#{green}#{match}#{normal}" }
>           .sub(%r((?<=:)\d+(?=:))) { |match| "#{pink}#{match}#{normal}" }
>     }
>   end
> end
>
>
> The problem, though, is that $! is still set after this block runs, and so
> Ruby still spits out its own exception message afterwards. I don't know how
> to stop it from doing this.
>
> I tried setting $!, but it's a read-only variable. Tried raising and
> rescuing another exception, which cleared $! for the rest of that at_exit
> block, but it was still around in the next at_exit block, and so Ruby still
> printed it out. Not sure what else to try.
>
> -Josh



-- 
  Matthew Kerwin, B.Sc (CompSci) (Hons)
  http://matthew.kerwin.net.au/