> > cons-cell is a terrible abstraction on modern hardware

> Could you expand on this?

Sure, that one is pretty easy. cons cells are effectively 2 pointers. Consequently, they are not guaranteed nor expected to be near one another in memory.

Now, that's not a big deal with respect to the first pointer. That contains the thing, so we always have to chase that down.

In a Lisp/Scheme cons-cell list, the second pointer needs to be referenced to get to the next cons cell. So, we have to chase a second pointer just to move to the next element.

Every time you chase a non-contiguous pointer like this, the processor may have to bring in a cache line and that's a big penalty.

Contrast this to say, an array/vector. To get to the next element you just add some small amount to the current index. It's likely already in the same cache line as the previous element.

Arrays/vectors have a big win over pointer-based lists in terms of locality of reference on a modern microprocessor.

There is a second problem with cons cells in that their abstraction in terms of the language also has problems:

"Programing Language: Why Lisp Do Not Have a Generic Copy-List Function" http://xahlee.info/UnixResource_dir/writ/lisp_equal_copy_lis... http://www.nhplace.com/kent/PS/EQUAL.html

What is so much better between Squirrel and Javascript? To my eye, they look pretty much the same.

And Javascript has an enormous ecosystem. While Squirrel has a very small niche of the not terribly large Lua ecosystem.

This isn't to knock Squirrel as a language, but I view this in the same light and Python vs. Ruby. The languages don't have enough better/different from one another for me to tell someone to switch if they already know one or the other.