$arg1 = "arg1";
$arg2 = "arg2";
$arg3 = "arg3";
 
sub f1 { return "1"; }
sub f2 { return "0"; }
sub f3 { return "3"; }

print "${\-+- f1( $arg1 )}";
print "${\+-+ f2( $arg2 )}";
print "${\-+- f3( $arg3 )}";
print "\n"