What's the meaning of die ref $res... ?

miguelele has asked for the wisdom of the Perl Monks concerning the following question:

Hi, I am handling errors in SOAP::LITE with the help of http://guide.soaplite.com/#error%20handling It works as I need, but I am stuck trying to understand this block of Perl code:

on_fault => sub { my($soap, $res) = @_;
    eval { die ref $res ? $res->faultstring : $soap->transport->status
+ };
    return ref $res ? $res : new SOAP::SOM;
  };
[download]

Specially, after it dies, I do not understand the meaning of ref $res ? $res->faultstring : $soap->transport->status Is it referencing or something?

Any didactic help will be really appreciated.

Regards

Comment on What's the meaning of die ref $res... ? Select or Download Code

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Re: What's the meaning of die ref $res... ? by Utilitarian (Vicar) on Jan 12, 2012 at 17:01 UTC
Look for the Ternary operator in the perlop doc. `ref $res ? $res->faultstring : $soap->transport->status` [download] Could be written as `if (ref $res){ #$res is a reference and not a scalar die $res->faultstring; # exit printing the fault } else{ die $soap->transport->status; #Exit with the current transport statu +s of the SOAP object }` [download] `print "Good ",qw(night morning afternoon evening)[(localtime)[2]/6]," fellow monks."`	[reply] [d/l] [select]
Re^2: What's the meaning of die ref $res... ? by miguelele (Beadle) on Jan 13, 2012 at 09:17 UTC
Thank you, I get it now! It is no easy to make a search for "ref" or "?" or ":" Regards	[reply]
Re^3: What's the meaning of die ref $res... ? by Utilitarian (Vicar) on Jan 13, 2012 at 11:15 UTC
Indeed, until you know what it's called (at which point you probably understand it) searching for the ternary op can be difficult ;) `print "Good ",qw(night morning afternoon evening)[(localtime)[2]/6]," fellow monks."`	[reply] [d/l]
Re: What's the meaning of die ref $res... ? by BrowserUk (Patriarch) on Jan 12, 2012 at 17:06 UTC
If you feed the code you are having trouble with in to Deparse,-p you get: `C:\>perl -MO=Deparse,-p -e"die ref $res ? $res->faultstring : $soap->t +ransport->status" die((ref($res) ? $res->faultstring : $soap->transport->status)); -e syntax OK` [download] And if we add a little horizontal whitespace to that: `die( ( ref( $res ) ? $res->faultstring : $soap->transport->status ) );` [download] You can see that the ref`( $res )` part is a conditional test to see if `$res` is a reference. If it is, then it passes `$res->faultstring` to die. Otherwise it passes: `$soap->transport->status` to die. With the rise and rise of 'Social' network sites: 'Computers are making people easier to use everyday' Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error. "Science is about questioning the status quo. Questioning authority". In the absence of evidence, opinion is indistinguishable from prejudice. The start of some sanity?	[reply] [d/l] [select]