This paper: https://cs.brown.edu/~sk/Publications/Papers/Published/pmmwplck-python-full-monty/paper.pdf

… has been out for several years now, and the CPython authors don’t seem to be taking any heed from it. The question one’s faced when viewing the inner-workings of CPython’s VM is:

Is Python a lazy language, or is it not? Should types and symbols be resolved through VM, or semantic analysis? Should there be explicit tree-building and DAG number-value optimization, or just shit out the bytecode?

Because the VM seems to build classes on-the-go [list of opcodes]. I am not pretending, and I don’t pretend, that I know enough about this, but would it be not better if they did a full semantic analysis, then emitted the bytecodes? So this way, the execution would be faster, albeit whilst introducing small lags for a more loaded semantic analysis?

Of course, the answer is clear: Python may not officially be a lazy language, but it virtually is one. class syntax, as the paper says, is a syntactic sugar around type with tree arguments. type with three arguments is invoked during runtime, it would be rather stupid, and slow to do semantics on a runtime function right!? So classes are not ‘really’ classes!

For further clearity, this:

cls = type("Cls", (), { "foo": "baar" })

is equal to this:

class Cls:
   foo = "bar"

They might have looked at this paper, and said ‘nah, don’t fix what’s broken’ and this exact attitude that Python community has, from top to bottom, is why I have not used it in about 2 years, and unless paid handsomely, won’t use it in any projects.

I believe Python needs to decide if it’s an scripting language, a cross-platform juggernaut like Java is, or is it what it exactly is, a piece of crap hyped out to high heavens!

These are my opinions, I don’t think I am educated enough for these to be facts. But look through your heart, compare CPython’s VM opcodes with JVM’s opcodes. JVM is a full register machine (whereas Python is a stack machine), with low-level opcodes designed to get things done fast and portable. It has an infrasturcture, and an echosystem. Several languages run on it, hell even Python itself runs on it!

Sadly, because that dang C FFI is so sweet, CPython seems to be de facto the Python implementation. And Python is not even badly specified like Perl is. I prefer a highly non-orthogonal language like Perl for scripting any day of the week. I use Perl a lot for preprocessing C source files, or just using it as AWK replacement. Is Python supposed to be that? Or Java? Decide goddamit.

So what we get from this is, Python is a simple AWK-ascended UNIX scripting language that lazy people have made into de facto Java! lol

Again, I am not very educated on this matter, please don’t take my opinion as facts. I just made this thread to share this nice paper and a bit of trivia.

Thanks.

  • Corbin@programming.devEnglish
    1·
    3 months ago

    I’ve only skimmed the paper, so let me know if I’ve missed something, ideally with a page number. Also, it’s late and I’m tired, so I’m not hyperlinking anything; sorry.

    I’m not sure what a “full semantic analysis” entails, but always keep Rice’s theorem in mind: there aren’t any interesting semantic analyses available for Turing-complete systems.

    Python is a descendant of Smalltalk. Like several of its cousins, particularly the famous ECMAScript, Python doesn’t have types or classes in the Smalltalk sense, but prototypes which form a class-like hierarchy. From the static-analysis point of view, whether a type is created or instantiated is a matter of Rice’s theorem.

    The ability to invoke type() at runtime is not lazy. Python is eager and strict; even generators are eager and strict, although they can cause stack frames to become “stale”; whether a stale stack frame is cleaned up is also a matter of Rice’s theorem.

    None of this prevents compilation of Python. The RPython toolchain first imports an application, evaluating all calls to type() and pre-building all classes; then, it statically analyzes all of the Python objects in memory and decompiles their bytecode to determine their behaviors. The resulting executable behaves as if it were started from a snapshot of the Python heap.

    Yes, CPython sucks. Use PyPy instead; also, use cffi to wrap C libraries.

  • Turun@feddit.de
    1·
    3 months ago

    Yes, python is between java (long compiles, faster execution) and perl (no compiles, slower execution). No, it won’t change that, because it’s pretty successful the way it is now.

    And yes, cffi is pretty dang sweet. Tons of scientific research runs on Numpy and pandas.