V:\>perl -MO=Deparse -e "$x = FOO + 7 + 9"
$x = 'FOO' + 7 + 9;
-e syntax OK

V:\>perl -MO=Deparse -e "use constant FOO => 8; $x = FOO + 7 + 9"
use constant ('FOO', 8);
$x = 24;
-e syntax OK

##</code><code>##

V:\>perl -MO=Deparse -e "sub foo {}; sub bar {};$x = bar foo 7, 9"
sub foo { }
sub bar { }
$x = bar(foo(7, 9));
-e syntax OK
V:\>perl -MO=Deparse -e "sub foo ($) {}; sub bar {};$x = bar foo 7, 9"
sub foo ($) { }
sub bar { }
$x = bar(foo(7), 9);
-e syntax OK