Just how are you 'passing'  "v=33" as an argument? To what are you passing it? Can you show an example of  "=" disappearing? Otherwise, an expression like  $v = 33 behaves as expected: an assignment to a variable, which yields the value of the assignment.

c:\@Work\Perl>perl -wMstrict -le
"sub S { print qq{S got $_[0]}; }
 ;;
 my $v = 0;
 print qq{\$v starts as $v};
 ;;
 S($v = 33);
 print qq{\$v now $v};
"
$v starts as 0
S got 33
$v now 33
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