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Comment by hindenburg | Hacker News Reader

You make some specific claims here that sound a little odd to this LISP and assembly language hacker.

Assembly language doesn't provide any datatypes. LISP does. Assembly language doesn't provide any type checking. LISP does. Assembly language doesn't provide automatic storage reclamation. LISP does. Assembly language doesn't provide naming. LISP does.

You also make a claim about L1 caches and locality of reference. Every LISP compiler writer, and every LISP garbage collector writer, knows about CDR-coding. We also know about how Cheney copying garbage collectors and their descendants like the Baker incremental collector compact data, precisely for locality of reference. The compiler writer of course is thinking about cache performance and how lines are mapped in particular target architectures.

You should probably educate yourself a little more about LISP if you are so interested in it as to make statements in a public forum.

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He was talking about macro assemblers, which often do provide naming and some level of type checking (and pure assembly is arguably at a lower level of abstraction than type systems, with separate instructions and registers for integers, pointers, floating-point etc).

I agree it's a somewhat odd comparison.

There are of course plenty of obvious and non-obvious ways to optimize linked lists, but even still they have poor performance characteristics, space efficiency and cache locality compared to alternative structures like arrays and even immutable arrays.

There's a reason Java, C#, Python etc store strings as immutable arrays; not only do they start from a generally better performance baseline than lists, but they too have well-understood optimization characteristics.

>"every LISP garbage collector writer, knows about CDR-coding."

I thought CDR needed hardware support as opposed it being a general programming technique, is that not correct?

I've only ever read about it on FAQs like in the following:

http://www.cs.cmu.edu/Groups/AI/html/faqs/lang/lisp/part2/fa...

I was only talking about the 'list of function calls' aspect of assembler and Lisp, not the type system. I agree that Lisp has a type system and assembler doesn't. Forth is another language that also has very simple syntax that approximates the 'list of function calls' style that I would say isn't unlike a macro assembler either.

I am writing a new language with built-in garbage collection that I think is quite superior to other languages. I have created a full standard library with almost 1,000 built-in functions and none of my data structures (lists, maps, trees, stacks, indexes, tables etc) contain pointers or linked lists (that use pointers). I sold over 30,000 copies of a language/database system in 1987 so I think your last comment is quite inappropriate. I have know about Lisp since I started CS in University in 1975.

Linked lists are horrible data structures when being used as well as when being freed (your garbage collection comment). I use simple dynamic multi-typed arrays instead of linked lists (pointers) and they can be freed in 1 chunk or a bigger version can be freed with a few memory de-allocations. I get full cache locality and improved speed of allocation and de-allocation.

I would love to see an incremental GC that can copy all linked lists nodes into contiguous memory automatically. Nice trick if you can do it but that doesn't help you if your linked list doesn't cause a GC.

Big time array fan here. I'd love to check out your language when you publish it. Sooner the better.. we need new ideas! Email in profile if you'd like to chat about it.

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