Functional Programming in Python • Hacker News Board

Re: Functional Programming in Python

#61

Post by nurettin » Fri, May 29, 2020, 5:55 AM UTC

snapetom wrote: post #21

BiteCode_dev wrote: post #13

How about writting modern and proper Python first? Not to mention designing a decent API? Let's examine the README example for a minute: user: Optional[User] if user is not None: balance = user.get_balance() if balance is not None: balance_credit = balance.credit_amount() if balance_credit is not None and balance_credit > 0: can_buy_stuff = True else: can_buy_stuff = False I don't know if it's been deliberatly twiste…

I'd like to know what happens to can_buy_stuff and the rest of the code when user is Not None and balance_credit is -1.

user can't buy stuff and one unfortunate developer will hunt the bug that charged someone with negative credit.

Re: Functional Programming in Python

#62

Post by FridgeSeal » Fri, May 29, 2020, 6:14 AM UTC

mdtusz wrote: post #60

FridgeSeal wrote: post #52

Functional programming in Python: Step 1: try to integrate more functional methods in your current Python programming due to their usefulness. Step 2: get increasingly frustrated, and then give up, because Guido and the Python devs seemingly hate functional programming and keep hobbling it.

A part of me is happy to see these types of tools introduced to python, but another part makes me wonder why people continue to use python when they see the value of things like `Option`/`Maybe`'s, `Result`'s, instead of just using a language with the features included from the start. In my experience, the initial ease and speed of development when using python doesn't nearly outweigh the medium to long-term costs of…

I don't have the skills to pull it off completely, or maintain it, but I've often toyed with the idea of a language/DSL that superficially looks and behaves like Python, but transpires down into Rust or something.

Mostly just to see what a language that 'feels like' Python would be like with the addition of things like proper Option/Result's and a couple of other features (stronger typing?).

Re: Functional Programming in Python

#63

Post by sobolevn » Fri, May 29, 2020, 8:19 AM UTC

Hi, author of `returns` here! Thanks a lot for sharing this link.

I would love to highlight several features of `0.14` release we are working on right now:

1. Typed `partial` and `curry` functions: https://returns.readthedocs.io/en/latest/pages/curry.html

2. `Future` and `FutureResult` containers for working with async Python! https://returns.readthedocs.io/en/latest/pages/future.html

3. Typed functional pipelines with very good type inference: https://returns.readthedocs.io/en/latest/pages/pipeline.html

It is going to be released soon, stay tuned!

Re: Functional Programming in Python

#64

Post by throwaway_pdp09 » Fri, May 29, 2020, 9:00 AM UTC

NoahTheDuke wrote: post #46

jennasys wrote: post #27

Earlier quoted context omitted.

lambda use in Python is discouraged in general. If you need something beyond an expression, PEP-8 encourages you to use a def in that case instead.

The issue with that is the lack of lexical scope. Lambdas have lexical scoping, def functions do not. To “fake” lexical scope, you have to use the nonlocal or global statements, which are gross and self-defeating.

Not sure I understand, defs have lexical scoping too, if you just read variables (or am I getting rusty?).

  x = 3

  def prt():
      print(x)

  prt()

prints 3, as expected.

It's when you assign that you need P3's global etc. annotations, and you can't assign in lambdas.