$x = 4;         # Scalar assignment operator (sassign)
($x) = 4;       # List assignment operator   (aassign)

$x x 4          # String repetition operator (repeat)
($x) x 4        # Scalar repetition operator (repeat/DOLIST)

\$x, $y         # The referencing isn't distributed.
\($x, $y)       # The referencing is distributed.

use Mod;        # Calls import.
use Mod ();     # Doesn't call import.

@a = ;          # Illegal
@a = ();        # Stub operator