in reply to check for existing value, else set to default

Is this what you meant? Taken literally, $a has a defined value, and the tertiary operator is unnecessary, so I presume you are looking for a default value kind of operation. 

$a = 'text';
$b = $a || '';

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Your third example is not reducible. At least, not by me.

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Re: Re: check for existing value, else set to default
by waswas-fng (Curate) on Apr 26, 2004 at 06:03 UTC 
    
$a = 0;
$a = $a || "1024";
if ($a == 1024) {
print "ack $a =  1024 rm -rf ~\n";
}

    [download]
    whoops.


    -Waswas
[reply]
[d/l]

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