sub r { $_[0] } # no-op? sub rr :lvalue { $_[0] } # no-op? $_ = 1; print ($_) + $_++; $_ = 1; print r($_) + $_++; $_ = 1; print $_ + $_++; $_ = 1; print $_ + ++$_; $_ = 1; print r(++$_) + r(++$_); $_ = 1; print ++$_ + ++$_; $_ = 1; print rr(++$_) + rr(++$_)++;