$_= ~/^\w+\s*=\s*\w+\s*\,\?\w+/ ;
Actually, it's worse than that. Because the = ~ is screwed up (should have been =~), the statement (if that's the statement that's actually in perlynewby's code (if that's actually perlynewby)) is assigning the 1s-complement of the numeric value of the result of the m// against $_ to $_ instead:
c:\@Work\Perl\monks>perl -wMstrict -le
"$_ = 'x=x,?x';
print qq{'$_'};
;;
$_= ~/^\w+\s*=\s*\w+\s*\,\?\w+/ ;
print qq{'$_'};
;;
$_ = '----';
print qq{'$_'};
;;
$_= ~/^\w+\s*=\s*\w+\s*\,\?\w+/ ;
print qq{'$_'};
"
'x=x,?x'
'4294967294'
'----'
'4294967295'
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