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Comment by saagarjha | Hacker News Reader

> The higher the language is, the slower it is. That’s why C and C++ are so much faster, they’re very close to the machine code language: the assembly language.

Wait until you see Rust ;)

> That means that new properties can be added, replaced and removed during execution time. This is not possible with languages like Java, for example, in which everything (classes, method, objects and variables) must be defined before program execution and can’t be dynamically changed after the app starts.

Nit: they can; this is just not normally done

> At the time of writing this article, the GitHub repo counts 15.3k stars and 2.9k forks.

Note that V8 is developed mostly outside of GitHub.

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> Wait until you see Rust ;)

Or Common Lisp. Or OCaml. Or Haskell. Or Dylan. Or...

Those are all higher languages however they are slow.

No, they aren't. That's the whole point. This idea that high level languages are slow is a pernicious myth.

How can say lisp, a language that touches the heap profusely, be faster than c or rust?

i've heard a lot about SBCL and the efficient machine code it generates. i'm guessing a lot of the heap stuff can be optimized away if the code is written right (e.g. via escape analysis or eliminating intermediate values). though i'm guessing that if you really want the best performance, you just end up writing C/Rust with a lot of parentheses :)

You have to compare apples and apples. Lisp can "touch the heap profusely" but it doesn't have to. You can trade off programming convenience for heap touching.

But GC technology has come a very long way, and GC's optimized for Lisp's particular pattern of heap touching have become exceptionally good. Such technology is now standard equipment in EVERY language EXCEPT C and C++, and even C and C++ have them as bolt-on accessories. For some kinds of tasks, Lisp can actually be faster than C or C++. This is why, for example, the Orbitz search engine was written in Common Lisp.

OK can I see some numbers?

Sure. What kind of numbers would you like to see?

That show that lisp is comparably fast as c.

The class of problems you can solve with a C program that doesn't touch the heap profusely is small. C programs that touch the heap profusely often do it in bad ways which are necessary so that they can be debugged to production. For instance, a commonly seen design decision in C programs is to avoid sharing objects, leading to increased memory use, increased calls to malloc and wasteful copying overhead. A Lisp program rarely calls the equivalent of strdup for instance; you don't worry about who is going to free this, and will two modules try to do it to the same object?

Not only that, with languages like Objective-C or C++, one can have high level code just like Python, Lisp or OCaml, yet the myth still stays.

> Wait until you see Rust

Rust is still just a really nice macro assembler.

Err, what?

Like every compiled language :/

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