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Very strange to see the core primitives of functional programming being sold as 'Pythonic'. I suppose we all look at the world from the perspective of our own

Very strange to see the core primitives of functional programming being sold as 'Pythonic'. I suppose we all look at the world from the perspective of our own experience.

kbenson 9y ago
> I suppose we all look at the world from the perspective of our own experience. Yes, but in addition to that, I think you can likely sell an idea to people much easier when it's couched in something they are already familiar with. There's been lots said about the functional programming capabilities of Rust, but if people don't already equate what they do as following some functional paradigm, they might find themselves uninterested in the discussion. I think Python especially, with its "one way to do it" and (my perception) how people adhere to "the way to do it in Python", there's a good chance some people don't really know when they are using common functional patterns.
- spyspy 9y ago
  > Python especially, with its "one way to do it" Despite being a core tenet of the language, Python is _really, really_ bad at following that rule. I agree with everything else you're saying, though. Those are still Python idioms even if they originated elsewhere.
  - codetrotter 9y ago
    How so? Comprehensions vs loops vs recursive functions vs in some cases map/reduce/filter is the only example I can think of.
    - strkek 9y ago
      There's also strings. 'foo ' + bar 'foo {}'.format(bar) 'foo %s' % bar f'foo {bar}'
      - BerislavLopac 9y ago
        As well as the string templates almost nobody knows about (https://docs.python.org/3.6/library/string.html#template-strings https://docs.python.org/3.6/library/string.html#template-str...): Template('$foo bar').substitute(foo='foo')
  - davidcuddeback 9y ago
    I think people take the "one way to do it" tenet a little too seriously. It comes from PEP20 [1], which to me seems to have a more jestful than dogmatic tone: > There should be one-- and preferably only one --obvious way to do it. > Although that way may not be obvious at first unless you're Dutch. If I remember my history correctly, this was poking fun as Perl's "TIMTOWTDI" [2]. It also says one obvious way to do it. It doesn't preclude there being more than one way. [1] https://www.python.org/dev/peps/pep-0020/ https://www.python.org/dev/peps/pep-0020/ [2] https://en.wikipedia.org/wiki/There%27s_more_than_one_way_to_do_it https://en.wikipedia.org/wiki/There%27s_more_than_one_way_to...
    - jerf 9y ago
      In 2004, "There should be only one way to do it" was a more realistic goal. 2004 puts us at Python 2.4 or so, but I think that's just when it got formalized into a PEP, it was around for a while before then. If we step back two years to 2002, we get to Python 2.1. We are now pre-generators, pre-with statement, pre-itertools, pre-decorators, and a lot of other things (useful itertools, etc.). There more often was only one sensible way to do a thing. Python evolved, but PEP20 didn't.
      - davidcuddeback 9y ago
        > 2004 puts us at Python 2.4 or so, but I think that's just when it got formalized into a PEP I didn't notice the date on the PEP, but I think you're right. I remember reading it when I learned Python circa 2002. Found this (from 1999): https://mail.python.org/pipermail/python-list/1999-June/001951.html https://mail.python.org/pipermail/python-list/1999-June/0019....
  - xapata 9y ago
    The "obvious way" changes over time, as the language improves.
tomsthumb 9y ago
Python has good facilities for a solid chunk of functional programming “in the small”. List comprehensions, map, filter, and reduce are all there with clear, easy to understand syntax. It’s no Haskell, but these are definitely niceties. That said, I don’t see where the author put forward the idea that functional programming is Pythonic so much as “these are functional things that are great in python, here are some analogs in rust”.
- ubernostrum 9y ago
  I feel like list comprehensions have always been emphasized as an important part of writing idiomatic Python. And as Python added more constructs in that vein (generator expressions, dict and set comprehensions) the tutorials people used didn't really keep up. In the same way, map and filter were often covered, but not always with an explanation of the style of programming they supported, or why that style could be useful. I do remember the original Dive Into Python did a good job of this, and of encouraging people to explore a more functional style, but I don't recall many other resources, at least from the (2004-ish) era when I was first learning Python, doing that. As a result I have to be a bit careful these days; I still use Python's more functional constructs regularly, but I've learned to go easy on them when collaborating with others, since I know a lot of people who learn Python now are using materials that mostly only touch on list comprehensions.
  - repsilat 9y ago
    The "real functional" map/reduce/filter functions tend to be discouraged by programmers and linters too. It is becoming (has become?) an established part of the culture -- "Lambda in a `map`? Use a list comprehension instead." I guess it's a "sheep as a lamb" thing -- "The 'functional way' is either points-free or pointless." Maybe it's better in Rust because the method-style `x.filter().map().reduce()` lets you read left-to-right, and the "global function" `reduce(map(filter(x)))` has to be read inside-out. If there is a good reason to do Python's global function way, maybe D's UFCS can bring them the best of both worlds.
    - ubernostrum 9y ago
tzahola 9y ago
I think it's nice that more and more languages take inspiration from the Python community. For example, I've recently found a way to use Python-like type hints in C++. Crazy, huh? The trick is to replace "auto" with the concrete type name, e.g.: auto x = 5; becomes: int x = 5;
- tathougies 9y ago
  This is a joke right?
  - tzahola 9y ago
    Joke? No, you can actually do this in C++!
    - tathougies 9y ago
      Of course you can do this in c++. The second form of your declaration is the standard way of doing things. How did you learn c++, that this was a surprise to you? Secondly, that’s not a ‘type hint’ and c++ did not get this from python. Prior to c++17, there was no auto and all declarations were like this. If anything, Python got the names from c++
apendleton 9y ago
Honestly I suspect that this stems from a perception particularly among people from a non-traditional CS background that "functional programming" is intimidating, whereas Python is seen as approachable in a get-shit-done kind of way for programming novices. Python definitely did co-opt a lot of traditionally functional stuff, but did it in a way that obviates needing to know what a monad is, concern oneself with functional purity, etc., so there's a community of people now who don't care about any of that but are still familiar with some of these idioms, and this post is meant to make Rust look more accessible to them in a way that "Rust supports functional programming idioms" would not.
- supergarfield 9y ago
  This is tangential to your main point, but: > did it in a way that obviates needing to know what a monad is, concern oneself with functional purity, Caring about both of these things in the context of functional programming essentially dates from the early 1990s. According to Wikipedia (I have no better source, but it matches what I know of pre-1990s functional languages), > Eugenio Moggi first described the general use of monads to structure programs in 1991. Functional programming existed before then. Scheme, an early functional language, is from the 1970s. It has basically all the FP idioms that you have in Python, is not pure, is dynamically typed, and the doc never once references monads. I'd actually say the definition of FP has shifted towards pure, category-theory oriented languages, but "traditionally functional stuff" definitely doesn't include monads.
  - coldtea 9y ago
    >Functional programming existed before then [1991]. Scheme, an early functional language, is from the 1970s. Lisp is even older, as was touted as the de facto functional language since forever. And earlier MLs didn't have monads either. And of course, just because Moggi described monads in 1991, it doesn't mean it didn't take over a decade for them to make any kind of significant dent. (Assuming that they have made much of a dent today, which outside the world of Haskell, their explicit (as opposed to implicit) use is close to 0, anyway).
  - willtim 9y ago
ceronman 9y ago
Python had the primitives of functional programming since its conception. Those are not exclusive of pure FP languages. Some particular names used in the examples were introduced by Python. For example the `enumerate` function or `zip`. I haven't seen those names used in programming languages older than Python, I know I might wrong. The point is that it's not crazy to believe that Rust design does borrow some things from Python (among other languages of course). The article is comparing some particular Python idioms with Rust. The fact that those are functional I think is not particularly relevant. It's like someone seeing a comparison of Java and Go and saying that those are just the principles of imperative programming, or object oriented programming.
- fjh 9y ago
  > Some particular names used in the examples were introduced by Python. For example the `enumerate` function or `zip`. I haven't seen those names used in programming languages older than Python, I know I might wrong. All the ML dialects that I know have a zip function and ML pre-dates Python by about 20 years. This is particularly relevant since Rust is clearly strongly influenced by ML. > The fact that those are functional I think is not particularly relevant. It's like someone seeing a comparison of Java and Go and saying that those are just the principles of imperative programming, or object oriented programming. The comparison feels right, but I think it would certainly be odd if somebody explained loops in Go as "a Java idiom".
- agumonkey 9y ago
  Python FP primitives came from an early friend or codev of Guido. He had experience in FP or Lisp and felt he needed them. Guido never really wanted that and just left them there. All these names and ideas are clearly rooted in FP circles
slaydemons 9y ago
Except the article contained non-functional concepts in it also. But hey at least you got to announce the fact you use/like functional programming languages.
ubernostrum 9y ago
It's possible for these constructs to be present in many languages and predate Python's adoption of them, and for it to be simultaneously true that a lot of idiomatic Python relies on these constructs.
c3534l 9y ago
I suppose it makes sense in weird way, since both Python and Rust have these features implemented in similar ways because it stems from more traditional functional programming. You could also compare Java to C++ on account of them both being inspired by C.

Very strange to see the core primitives of functional programming being sold as 'Pythonic'. I suppose we all look at the world from the perspective of our own experience.

kbenson 9y ago

> I suppose we all look at the world from the perspective of our own experience. Yes, but in addition to that, I think you can likely sell an idea to people much easier when it's couched in something they are already familiar with. There's been lots said about the functional programming capabilities of Rust, but if people don't already equate what they do as following some functional paradigm, they might find themselves uninterested in the discussion. I think Python especially, with its "one way to do it" and (my perception) how people adhere to "the way to do it in Python", there's a good chance some people don't really know when they are using common functional patterns.

spyspy 9y ago
> Python especially, with its "one way to do it" Despite being a core tenet of the language, Python is _really, really_ bad at following that rule. I agree with everything else you're saying, though. Those are still Python idioms even if they originated elsewhere.
- codetrotter 9y ago
  How so? Comprehensions vs loops vs recursive functions vs in some cases map/reduce/filter is the only example I can think of.
  - strkek 9y ago
    There's also strings. 'foo ' + bar 'foo {}'.format(bar) 'foo %s' % bar f'foo {bar}'
    - BerislavLopac 9y ago
      As well as the string templates almost nobody knows about (https://docs.python.org/3.6/library/string.html#template-strings https://docs.python.org/3.6/library/string.html#template-str...): Template('$foo bar').substitute(foo='foo')
- davidcuddeback 9y ago
  I think people take the "one way to do it" tenet a little too seriously. It comes from PEP20 [1], which to me seems to have a more jestful than dogmatic tone: > There should be one-- and preferably only one --obvious way to do it. > Although that way may not be obvious at first unless you're Dutch. If I remember my history correctly, this was poking fun as Perl's "TIMTOWTDI" [2]. It also says one obvious way to do it. It doesn't preclude there being more than one way. [1] https://www.python.org/dev/peps/pep-0020/ https://www.python.org/dev/peps/pep-0020/ [2] https://en.wikipedia.org/wiki/There%27s_more_than_one_way_to_do_it https://en.wikipedia.org/wiki/There%27s_more_than_one_way_to...
  - jerf 9y ago
    In 2004, "There should be only one way to do it" was a more realistic goal. 2004 puts us at Python 2.4 or so, but I think that's just when it got formalized into a PEP, it was around for a while before then. If we step back two years to 2002, we get to Python 2.1. We are now pre-generators, pre-with statement, pre-itertools, pre-decorators, and a lot of other things (useful itertools, etc.). There more often was only one sensible way to do a thing. Python evolved, but PEP20 didn't.
    - davidcuddeback 9y ago
      > 2004 puts us at Python 2.4 or so, but I think that's just when it got formalized into a PEP I didn't notice the date on the PEP, but I think you're right. I remember reading it when I learned Python circa 2002. Found this (from 1999): https://mail.python.org/pipermail/python-list/1999-June/001951.html https://mail.python.org/pipermail/python-list/1999-June/0019....
- xapata 9y ago
  The "obvious way" changes over time, as the language improves.

tomsthumb 9y ago

Python has good facilities for a solid chunk of functional programming “in the small”. List comprehensions, map, filter, and reduce are all there with clear, easy to understand syntax. It’s no Haskell, but these are definitely niceties. That said, I don’t see where the author put forward the idea that functional programming is Pythonic so much as “these are functional things that are great in python, here are some analogs in rust”.

ubernostrum 9y ago
I feel like list comprehensions have always been emphasized as an important part of writing idiomatic Python. And as Python added more constructs in that vein (generator expressions, dict and set comprehensions) the tutorials people used didn't really keep up. In the same way, map and filter were often covered, but not always with an explanation of the style of programming they supported, or why that style could be useful. I do remember the original Dive Into Python did a good job of this, and of encouraging people to explore a more functional style, but I don't recall many other resources, at least from the (2004-ish) era when I was first learning Python, doing that. As a result I have to be a bit careful these days; I still use Python's more functional constructs regularly, but I've learned to go easy on them when collaborating with others, since I know a lot of people who learn Python now are using materials that mostly only touch on list comprehensions.
- repsilat 9y ago
  The "real functional" map/reduce/filter functions tend to be discouraged by programmers and linters too. It is becoming (has become?) an established part of the culture -- "Lambda in a `map`? Use a list comprehension instead." I guess it's a "sheep as a lamb" thing -- "The 'functional way' is either points-free or pointless." Maybe it's better in Rust because the method-style `x.filter().map().reduce()` lets you read left-to-right, and the "global function" `reduce(map(filter(x)))` has to be read inside-out. If there is a good reason to do Python's global function way, maybe D's UFCS can bring them the best of both worlds.
  - ubernostrum 9y ago

tzahola 9y ago

I think it's nice that more and more languages take inspiration from the Python community. For example, I've recently found a way to use Python-like type hints in C++. Crazy, huh? The trick is to replace "auto" with the concrete type name, e.g.: auto x = 5; becomes: int x = 5;

tathougies 9y ago
This is a joke right?
- tzahola 9y ago
  Joke? No, you can actually do this in C++!
  - tathougies 9y ago
    Of course you can do this in c++. The second form of your declaration is the standard way of doing things. How did you learn c++, that this was a surprise to you? Secondly, that’s not a ‘type hint’ and c++ did not get this from python. Prior to c++17, there was no auto and all declarations were like this. If anything, Python got the names from c++

apendleton 9y ago

Honestly I suspect that this stems from a perception particularly among people from a non-traditional CS background that "functional programming" is intimidating, whereas Python is seen as approachable in a get-shit-done kind of way for programming novices. Python definitely did co-opt a lot of traditionally functional stuff, but did it in a way that obviates needing to know what a monad is, concern oneself with functional purity, etc., so there's a community of people now who don't care about any of that but are still familiar with some of these idioms, and this post is meant to make Rust look more accessible to them in a way that "Rust supports functional programming idioms" would not.

supergarfield 9y ago
This is tangential to your main point, but: > did it in a way that obviates needing to know what a monad is, concern oneself with functional purity, Caring about both of these things in the context of functional programming essentially dates from the early 1990s. According to Wikipedia (I have no better source, but it matches what I know of pre-1990s functional languages), > Eugenio Moggi first described the general use of monads to structure programs in 1991. Functional programming existed before then. Scheme, an early functional language, is from the 1970s. It has basically all the FP idioms that you have in Python, is not pure, is dynamically typed, and the doc never once references monads. I'd actually say the definition of FP has shifted towards pure, category-theory oriented languages, but "traditionally functional stuff" definitely doesn't include monads.
- coldtea 9y ago
  >Functional programming existed before then [1991]. Scheme, an early functional language, is from the 1970s. Lisp is even older, as was touted as the de facto functional language since forever. And earlier MLs didn't have monads either. And of course, just because Moggi described monads in 1991, it doesn't mean it didn't take over a decade for them to make any kind of significant dent. (Assuming that they have made much of a dent today, which outside the world of Haskell, their explicit (as opposed to implicit) use is close to 0, anyway).
- willtim 9y ago

ceronman 9y ago

Python had the primitives of functional programming since its conception. Those are not exclusive of pure FP languages. Some particular names used in the examples were introduced by Python. For example the `enumerate` function or `zip`. I haven't seen those names used in programming languages older than Python, I know I might wrong. The point is that it's not crazy to believe that Rust design does borrow some things from Python (among other languages of course). The article is comparing some particular Python idioms with Rust. The fact that those are functional I think is not particularly relevant. It's like someone seeing a comparison of Java and Go and saying that those are just the principles of imperative programming, or object oriented programming.

fjh 9y ago
> Some particular names used in the examples were introduced by Python. For example the `enumerate` function or `zip`. I haven't seen those names used in programming languages older than Python, I know I might wrong. All the ML dialects that I know have a zip function and ML pre-dates Python by about 20 years. This is particularly relevant since Rust is clearly strongly influenced by ML. > The fact that those are functional I think is not particularly relevant. It's like someone seeing a comparison of Java and Go and saying that those are just the principles of imperative programming, or object oriented programming. The comparison feels right, but I think it would certainly be odd if somebody explained loops in Go as "a Java idiom".
agumonkey 9y ago
Python FP primitives came from an early friend or codev of Guido. He had experience in FP or Lisp and felt he needed them. Guido never really wanted that and just left them there. All these names and ideas are clearly rooted in FP circles

slaydemons 9y ago

Except the article contained non-functional concepts in it also. But hey at least you got to announce the fact you use/like functional programming languages.

ubernostrum 9y ago

It's possible for these constructs to be present in many languages and predate Python's adoption of them, and for it to be simultaneously true that a lot of idiomatic Python relies on these constructs.

c3534l 9y ago

I suppose it makes sense in weird way, since both Python and Rust have these features implemented in similar ways because it stems from more traditional functional programming. You could also compare Java to C++ on account of them both being inspired by C.