6 ms·

This does NOT mean Python will get Tail Call Optimization, as Guido cannot be shown The Light, and has decided.

rpcope1 2y ago
That's probably one of the more frustrating things about Python. Each release it gets all sorts of questionable new syntax (including the very strange pattern matching "feature" that kind of sucks compared to something like Erlang or Scala), but we never get real useful quality of life improvements for basic functional programming like TCO or multi line lambdas
- jgalt212 2y ago
  The utility value of multi-line lambdas is real, but the readability of these is terrible. And Python prizes readability. So you know where this initiative will end up.
  - saagarjha 2y ago
    Nothing more readable than a triply-nested list comprehension on an object that exists only to vend its __getattr__ for some unholy DSL
    - pinoy420 2y ago
      Annoying. Because it “compiles” to less optimal code than writing it explicitly.
  - vrighter 2y ago
    I personally find python to be highly UNreadable, especially with all of its syntax and braindead scoping rules
- throwaway81523 2y ago
  Python has always been unashamedly imperative, with some functional features entering by slipping through the cracks. The pattern matching thing seemed ok to me when I tried it, but I haven't used it except briefly, since I'm still mostly on Python 3.9. Interestingly, Python has been losing users to Rust. I don't entirely understand that, other than everyone saying how Rust's tooling is so much better.
  - flakes 2y ago
    > Python has been losing users to Rust. I don't entirely understand that, other than everyone saying how Rust's tooling is so much better. Not to rust, but to Go and C++ for myself. The biggest motivating factor is deployment ease. It is so difficult to offer a nice client install process when large virtual environments are involved. Static executables solve so many painpoints for me in this arena. Rust would probably shine here as well. If its for some internal bespoke process, I do enjoy using Python. For tooling shipped to client environments, I now tend to steer clear of it.
    - sieve 2y ago
      > For tooling shipped to client environments, I now tend to steer clear of it. A guy on r/WritingWithAI is building a new writing assistant tool using python and pyQt. He is not a SE by trade. Even so, the installation instructions are: - Install Python from the Windows app store - Windows + R -> cmd -> pip install ... - Then run python main.py This is fine for technical people. Not regular folks. For most people, these incantations to be typed as-is in a black window mean nothing and it is a terrible way of delivering a piece of software to the end-user.
    - pjmlp 2y ago
      As someone that always kept a foot on C++ land, dispite mostly working on managed languages, I would that by C++17 (moreso now in C++23), dispite all its quirks and warts, C++ has become good enough that I can write Python like code with it. Maybe it is only a thing to those of us already damaged with C++, and with enough years experience using it, but there are still plenty of such folks around to matter, specially to GPU vendors, and compiler writers.
      - cempaka 2y ago
        Are there any books or curricula you'd recommend to someone starting out, who wants to learn a more modern style? My main worry is just that everything is going to be geared to C++11 (or worse, 98).
- dragonwriter 2y ago
  > we never get real useful quality of life improvements for basic functional programming like TCO or multi line lambdas A lambda can be as big of an expression as you want, including spanning multiple lines; it can't (because it is an expression) include statements, which is only different than lambdas in most functional languages in that Python actually has statements.
  - kqr 2y ago
    > most functional languages Most popular functional languages I can think of except maybe Haskell has statements!
- pinoy420 2y ago
  The choice of “unique” verbs is weird too. Case match. Try except?
  - maleldil 2y ago
    `match/case` looks absolutely fine to me. What's the problem? `try/except` is definitely weird, though.
ehsankia 2y ago
Guido is no longer BDFL though, it's the steering committee that decides.
- thunkingdeep 2y ago
  Ah, you’re correct. My comment was mainly meant as a tongue in cheek remark to point out that this definition of tailcall is wholly separate from Python function objects and merely an implementation detail.
- riffraff 2y ago
  the steering committee seems way less conservative than Guido, right? Looking at python from the outside a lot of changes since GvR stepped down seem like stuff he'd not have been fond of.
  - pansa2 2y ago
    Any examples? The biggest change since Guido stepped down has been the addition of pattern matching, which he was strongly in favour of. Moreover, Guido is in favour of ongoing addition of major new features (like pattern matching), worrying that without them Python would become a “legacy language”: https://discuss.python.org/t/pep-8012-frequently-asked-questions/487/2 https://discuss.python.org/t/pep-8012-frequently-asked-quest...
    - pinoy420 2y ago
      Pattern matching seems like a cool feature that was added just because it was cool. I think the syntax is really odd too - apparently to “be pythonic”. I really see no use for it other than to “look smart”. The fact that case match (switch case is a much better description) is expanded to practically a huge if else is disturbing. Similarly the walrus operator. Other than an answer to “what is a new feature of python that you like” interview trivia question, really, who has actually used it?
      - pansa2 2y ago
beagle3 2y ago
It is not an optimization ; it changes program semantics - converts programs that will run out of stack eventually regardless of the amount of available memory (and raise exceptions an the process, for example, which a program might rely on. Either way, semantics are changed) It should only be called Tail Call Elimination.
- flakes 2y ago
  > converts programs that will run out of stack eventually regardless of the amount of available memory (and raise exceptions an the process, for example, which a program might rely on https://xkcd.com/1172/ https://xkcd.com/1172/
- dragonwriter 2y ago
  By that standard, any optimization that changes scaling in any dimension changes semantics, which, well, I’m not saying its wrong, but I would say it is exactly what people looking for optimization want.
  - dataflow 2y ago
    > By that standard, any optimization that changes scaling in any dimension changes semantics That doesn't follow. This isn't like going from driving a car to flying an airplane. It's like going from driving a car to just teleporting instantly. (Except it's about space rather than time.) It's a difference in degree (optimization), yes, but by a factor of infinity (O(n) overhead to 0 overhead). At that point it's not unreasonable to consider it a difference in kind (semantics).
    - tomsmeding 2y ago
      Modern C compilers are able to transform something like this: for (int i = 0; i < n; i++) a += i; To: a += n * (n+1) / 2; Is this an optimisation or a change in program semantics? I've never heard anyone call it anything slse than an optimisation.
      - 2y ago
coldtea 2y ago
Hasn't Guido step down from BD anyway?

That's probably one of the more frustrating things about Python. Each release it gets all sorts of questionable new syntax (including the very strange pattern matching "feature" that kind of sucks compared to something like Erlang or Scala), but we never get real useful quality of life improvements for basic functional programming like TCO or multi line lambdas

jgalt212 2y ago
The utility value of multi-line lambdas is real, but the readability of these is terrible. And Python prizes readability. So you know where this initiative will end up.
- saagarjha 2y ago
  Nothing more readable than a triply-nested list comprehension on an object that exists only to vend its __getattr__ for some unholy DSL
  - pinoy420 2y ago
    Annoying. Because it “compiles” to less optimal code than writing it explicitly.
- vrighter 2y ago
  I personally find python to be highly UNreadable, especially with all of its syntax and braindead scoping rules
throwaway81523 2y ago
Python has always been unashamedly imperative, with some functional features entering by slipping through the cracks. The pattern matching thing seemed ok to me when I tried it, but I haven't used it except briefly, since I'm still mostly on Python 3.9. Interestingly, Python has been losing users to Rust. I don't entirely understand that, other than everyone saying how Rust's tooling is so much better.
- flakes 2y ago
  > Python has been losing users to Rust. I don't entirely understand that, other than everyone saying how Rust's tooling is so much better. Not to rust, but to Go and C++ for myself. The biggest motivating factor is deployment ease. It is so difficult to offer a nice client install process when large virtual environments are involved. Static executables solve so many painpoints for me in this arena. Rust would probably shine here as well. If its for some internal bespoke process, I do enjoy using Python. For tooling shipped to client environments, I now tend to steer clear of it.
  - sieve 2y ago
    > For tooling shipped to client environments, I now tend to steer clear of it. A guy on r/WritingWithAI is building a new writing assistant tool using python and pyQt. He is not a SE by trade. Even so, the installation instructions are: - Install Python from the Windows app store - Windows + R -> cmd -> pip install ... - Then run python main.py This is fine for technical people. Not regular folks. For most people, these incantations to be typed as-is in a black window mean nothing and it is a terrible way of delivering a piece of software to the end-user.
  - pjmlp 2y ago
    As someone that always kept a foot on C++ land, dispite mostly working on managed languages, I would that by C++17 (moreso now in C++23), dispite all its quirks and warts, C++ has become good enough that I can write Python like code with it. Maybe it is only a thing to those of us already damaged with C++, and with enough years experience using it, but there are still plenty of such folks around to matter, specially to GPU vendors, and compiler writers.
    - cempaka 2y ago
      Are there any books or curricula you'd recommend to someone starting out, who wants to learn a more modern style? My main worry is just that everything is going to be geared to C++11 (or worse, 98).
dragonwriter 2y ago
> we never get real useful quality of life improvements for basic functional programming like TCO or multi line lambdas A lambda can be as big of an expression as you want, including spanning multiple lines; it can't (because it is an expression) include statements, which is only different than lambdas in most functional languages in that Python actually has statements.
- kqr 2y ago
  > most functional languages Most popular functional languages I can think of except maybe Haskell has statements!
pinoy420 2y ago
The choice of “unique” verbs is weird too. Case match. Try except?
- maleldil 2y ago
  `match/case` looks absolutely fine to me. What's the problem? `try/except` is definitely weird, though.

ehsankia 2y ago

Guido is no longer BDFL though, it's the steering committee that decides.

thunkingdeep 2y ago
Ah, you’re correct. My comment was mainly meant as a tongue in cheek remark to point out that this definition of tailcall is wholly separate from Python function objects and merely an implementation detail.
riffraff 2y ago
the steering committee seems way less conservative than Guido, right? Looking at python from the outside a lot of changes since GvR stepped down seem like stuff he'd not have been fond of.
- pansa2 2y ago
  Any examples? The biggest change since Guido stepped down has been the addition of pattern matching, which he was strongly in favour of. Moreover, Guido is in favour of ongoing addition of major new features (like pattern matching), worrying that without them Python would become a “legacy language”: https://discuss.python.org/t/pep-8012-frequently-asked-questions/487/2 https://discuss.python.org/t/pep-8012-frequently-asked-quest...
  - pinoy420 2y ago
    Pattern matching seems like a cool feature that was added just because it was cool. I think the syntax is really odd too - apparently to “be pythonic”. I really see no use for it other than to “look smart”. The fact that case match (switch case is a much better description) is expanded to practically a huge if else is disturbing. Similarly the walrus operator. Other than an answer to “what is a new feature of python that you like” interview trivia question, really, who has actually used it?
    - pansa2 2y ago

beagle3 2y ago

It is not an optimization ; it changes program semantics - converts programs that will run out of stack eventually regardless of the amount of available memory (and raise exceptions an the process, for example, which a program might rely on. Either way, semantics are changed) It should only be called Tail Call Elimination.

flakes 2y ago
> converts programs that will run out of stack eventually regardless of the amount of available memory (and raise exceptions an the process, for example, which a program might rely on https://xkcd.com/1172/ https://xkcd.com/1172/
dragonwriter 2y ago
By that standard, any optimization that changes scaling in any dimension changes semantics, which, well, I’m not saying its wrong, but I would say it is exactly what people looking for optimization want.
- dataflow 2y ago
  > By that standard, any optimization that changes scaling in any dimension changes semantics That doesn't follow. This isn't like going from driving a car to flying an airplane. It's like going from driving a car to just teleporting instantly. (Except it's about space rather than time.) It's a difference in degree (optimization), yes, but by a factor of infinity (O(n) overhead to 0 overhead). At that point it's not unreasonable to consider it a difference in kind (semantics).
  - tomsmeding 2y ago
    Modern C compilers are able to transform something like this: for (int i = 0; i < n; i++) a += i; To: a += n * (n+1) / 2; Is this an optimisation or a change in program semantics? I've never heard anyone call it anything slse than an optimisation.
    - 2y ago

coldtea 2y ago

Hasn't Guido step down from BD anyway?