Return value in ternary

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

Hi,

Can you have a ternary in 'return'?

my $flag = 'yes';

my $return_value = test($flag);
# return 'yes'

$flag = '';
$return_value = test($flag);
# return 'none'


sub test() {
    my $value = shift;
    return $value ? $value : 'none';
    # is the above line valid?
}
[download]

Thank you :)

Comment on Return value in ternary Download Code

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Re: Return value in ternary by ikegami (Patriarch) on Mar 29, 2010 at 16:33 UTC
I'm not sure why you asking this since your code clearly demonstrates that it does work. `return` accepts any expression. The only question might be one of precedence. `Does return $value ? $value : 'none'; mean return ( $value ? $value : 'none' ); or ( return $value ) ? $value : 'none'; ?` [download] If you're not sure of the precedence, a simple test will tell you. (Again, you already did that, so I don't know why you are asking.) Either way, you can state the precedence you desire explicitly using parens.	[reply] [d/l] [select]
Re: Return value in ternary by JavaFan (Canon) on Mar 29, 2010 at 16:37 UTC
`# is the above line valid?` Is it really easier to compose a post, then to just run the code and see if the compiler throws an error?	[reply] [d/l]
Re: Return value in ternary by toolic (Bishop) on Mar 29, 2010 at 16:16 UTC
Yes. And you can prove it to yourself by adding a couple of strategically-placed prints to your code: `print "$return_value\n";` [download] On a side note, use strict and warnings, and clean up the warnings you get: `sub test {` [download]	[reply] [d/l] [select]
Re: Return value in ternary by ramlight (Friar) on Mar 29, 2010 at 16:13 UTC
Yes, you can return undef as well as a value. You would need to do a defined test in order to differentiate between undef and false.	[reply]
Re: Return value in ternary by Anonymous Monk on Mar 30, 2010 at 14:18 UTC
Thanks all :) I ran the code before posting. Though I got the result I expected, I wasn't sure whether it was valid perl code in the sense of whether people would actually write it that way.	[reply]


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