4 ms·

I wish that you could use typed Python to speed up the execution of the program instead of them just being hints.

by ZephyrBlu 6y ago

m_mueller 6y ago
afaik that was first planned for Python 4 and then dropped again :(
- ZephyrBlu 6y ago
  Any links on it being planned for Python 4? I didn't know they'd ever even considered it.
  - m_mueller 6y ago
    I think that the mentions of that have been deleted from the relevant PEP since, but e.g. https://www.reddit.com/r/Python/comments/7zvyhx/pep_563_mentions_python_40_whats_going_on/ https://www.reddit.com/r/Python/comments/7zvyhx/pep_563_ment... is also asking about it.
isoprophlex 6y ago
Not exactly what you're talking about, but... For some types of functions, Numba's JIT offers some pretty nice speed ups. It can infer function types (or you supply them yourself) and compiles to optimized machine code
chriswarbo 6y ago
It's tricky, since only the typed part can be sped up, and there will usually be lots of back-and-forth between typed and untyped code; which requires conversions and checks. For comparison, Racket has gradual typing which gives a speed boost when everything is typed, but can end up much slower if anything remains untyped, e.g. see figure 3 in http://www.ccis.northeastern.edu/home/types/publications/gradual-dead/pre-treatment.pdf http://www.ccis.northeastern.edu/home/types/publications/gra... Python would probably be even worse, since it's "more dynamic" than Racket; e.g. there are many hooks that can run arbitrary code (like dunder methods), and there's little encapsulation so values may get swapped out via monkey-patching at any time.
Jiejeing 6y ago
But that is precisely what mypyc[0] is doing! It is part of mypy, and it compiles type-valid python files to cpython binary extensions, and takes advantage of a lot of shortcuts available to cut execution time. It is still a bit early to advocate for its use everywhere, and has it drawbacks (extensions compiled with mypyc will also typecheck the inputs and outputs of the module at runtime, which is great for improving code quality and validity of the annotations, but also means you may get TypeErrors in production if you hit a bad edge case). If there is no shortcut it will fallback to normal, slow, python performance, with some smallish benefits (e.g. vtables for attribute lookups, no parsing time, etc). [0] https://mypyc.readthedocs.io/ https://mypyc.readthedocs.io/
- codethief 6y ago
  That's really neat, I hadn't heard of mypyc! How does it compare to Nuitka? https://nuitka.net https://nuitka.net
  - Jiejeing 6y ago
    I have not ran benchmarks, I would expect Nuitka to be more mature and optimized, but I really like the idea of having it bound with the type-checker.
goodpoint 6y ago
Nim feels very close to a typed Python.

I wish that you could use typed Python to speed up the execution of the program instead of them just being hints.

m_mueller 6y ago

afaik that was first planned for Python 4 and then dropped again :(

ZephyrBlu 6y ago
Any links on it being planned for Python 4? I didn't know they'd ever even considered it.
- m_mueller 6y ago
  I think that the mentions of that have been deleted from the relevant PEP since, but e.g. https://www.reddit.com/r/Python/comments/7zvyhx/pep_563_mentions_python_40_whats_going_on/ https://www.reddit.com/r/Python/comments/7zvyhx/pep_563_ment... is also asking about it.

isoprophlex 6y ago

Not exactly what you're talking about, but... For some types of functions, Numba's JIT offers some pretty nice speed ups. It can infer function types (or you supply them yourself) and compiles to optimized machine code

chriswarbo 6y ago

It's tricky, since only the typed part can be sped up, and there will usually be lots of back-and-forth between typed and untyped code; which requires conversions and checks. For comparison, Racket has gradual typing which gives a speed boost when everything is typed, but can end up much slower if anything remains untyped, e.g. see figure 3 in http://www.ccis.northeastern.edu/home/types/publications/gradual-dead/pre-treatment.pdf http://www.ccis.northeastern.edu/home/types/publications/gra... Python would probably be even worse, since it's "more dynamic" than Racket; e.g. there are many hooks that can run arbitrary code (like dunder methods), and there's little encapsulation so values may get swapped out via monkey-patching at any time.

Jiejeing 6y ago

But that is precisely what mypyc[0] is doing! It is part of mypy, and it compiles type-valid python files to cpython binary extensions, and takes advantage of a lot of shortcuts available to cut execution time. It is still a bit early to advocate for its use everywhere, and has it drawbacks (extensions compiled with mypyc will also typecheck the inputs and outputs of the module at runtime, which is great for improving code quality and validity of the annotations, but also means you may get TypeErrors in production if you hit a bad edge case). If there is no shortcut it will fallback to normal, slow, python performance, with some smallish benefits (e.g. vtables for attribute lookups, no parsing time, etc). [0] https://mypyc.readthedocs.io/ https://mypyc.readthedocs.io/

codethief 6y ago
That's really neat, I hadn't heard of mypyc! How does it compare to Nuitka? https://nuitka.net https://nuitka.net
- Jiejeing 6y ago
  I have not ran benchmarks, I would expect Nuitka to be more mature and optimized, but I really like the idea of having it bound with the type-checker.

goodpoint 6y ago

Nim feels very close to a typed Python.