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.

  • lolcatnipEnglish
    3·
    3 months ago

    Historically Python has done no semantic analysis at all, and as far as I know CPython still ignores type annotations except for checking their syntax and (I think) checking that type expressions can be evaluated as regular expressions. It’s also one if the slowest languages around, and it used to be much worse in the 1.x days. The only actual declarations are global and nonlocal, unless they’ve added something else recently. Everything else that looks like a declaration is actually a statement executed for its side effects. The super function used to only be callable with two arguments, because automatically supplying self and the lexically enclosing class was considered too magical.

    If you’re looking for something like Java or C#, Python isn’t for you. It was designed for use cases like fancy scripts and small applications that aren’t CPU bound. It’s about as dynamic as a language can be, meaning it’s possible to break almost any analysis you might do with a call to eval, and a lot of what you’d expect to be core language primitives, like accessing a field of an object, can execute arbitrary code.