You probably jest, but perl introduced simple arrays and hashes long before introducing references, and this created a lot of confusion later. Very simple json-like structures are pretty confusing in perl now. In most other dynamic languages distinction between array and a reference to an array is nonexistent, thankfully.

There're some actually exotic data structures, like pseudo-hashes. And perl can do this! $x = \$x

But having switched to ruby 15 years ago I never missed this particular quirk.

Distinguishing between the two can have massive performance impacts. There is also the reason that perl is closer to C than a lot of other languages in this regard.

Copying (often happens when passing an arg to a function / class) a reference is much quicker (only a 4 or 8 byte copy depending on arch) than doing either a single level shallow copy (4 x length(array) or 8 x length(array) bytes). Obviously the larger the size of the array the larger the impact.

well, then why bother copyiing at all? ruby passes references everywhere. Those are not pointers, of course, but for small arrays AFAIR those arrays (pointers to actual data) are contained in the reference itself. And logically it simplifies things soo much.