This will accommodate the case when $seclar is Zero
Not needed: 
$ perl -MO=Deparse -e 'while (my $scalar = <$TEST>) {1}'
while (defined(my $scalar = <$TEST>)) {
    do {
        '???'
    };
}
-e syntax OK

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Relevant: To Kill a Meme: while(defined($line = <>))

لսႽ† ᥲᥒ⚪⟊Ⴙᘓᖇ Ꮅᘓᖇ⎱ Ⴙᥲ𝇋ƙᘓᖇ

In reply to Re^2: intersection of scalar with 1D array and 2D array Matlab=>Perl by choroba
in thread intersection of scalar with 1D array and 2D array Matlab=>Perl by f77coder

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