6 ms·

Zed is making a number of points, so I don't want to sound like I'm arguing against all of them. But particularly on the matter of each... if all we were talk

Zed is making a number of points, so I don't want to sound like I'm arguing against all of them. But particularly on the matter of each... if all we were talking about were each I think Zed would have an excellent point. But wrapped up with each are all of the other fantastic enumerable methods like map/collect, select/find, inject/reduce, as well as each_cons, each.with_index, map.with_index, etc. These are where the power and expressiveness of ruby really come into play. For example: users.select(&:meets_some_critera?).each(&:update!) You could totally do that in a for each loop if you wanted. But it isn't really composable. While this works for the basic update... for user in users do user.update! if user.meets_criteria? end ... what if you wanted to then sum up the new account balances? In the first example, you'd just chain on a couple more enumerable methods: users.select(&:meets_some_critera?).each(&:update!) .map(&:account_balance).inject(&:+) With the for each construct you'd have to pass in an accumulator variable and keep track of whether to sum or not. While you certainly can do it in a for each construct, I'd argue that you'd be missing out on what makes ruby, ruby. And getting beginners in that more functional(ish) frame of mind sooner rather than later is a very good thing. --edited a few times for formatting/clarity

zedshaw 14y ago
You are right, and once again I am not against using functional programming, OOP, message passing, or any of the things I mention about .each. I'm against using .each as a first looping construct. In fact, go look at your supposedly better last line of code and tell me if you think a newbie would even begin to comprehend that? Hell I'm a programming veteran and Ruby veteran and I want to metaphorically punch you in the gonads for that line of code.
- cantankerous 14y ago
  This is a good point. To play a little off your blog post, a person new to Ruby could view the second line of code more as an idiomatic expression (which it's not really, but it can have the appearance of being one) in that it doesn't make obvious logical sense and is harder to translate to a more familiar language...giving a "raising ravens" (Spanish) vs. "can of worms" (English) scenario. I think it'd be kinda cool if one could develop sort of a "ruby-normal-form" that could take some ruby expressions and translate them into a more normalized form using things like for-loops, etc....granted normalizing a lot of ruby code might be hard, intractable, or maybe even impossible.
  - philwelch 14y ago
    If it threw in explicit returns at the end of each method and added back in all the optional parentheses, you'd be close to the average "Ruby code written by people who don't know Ruby that well" codebases you see in the wild so often.
- rauljara 14y ago
  To clarify, I don't think my original post implied that you were against teaching people how to learn each. Nor do I want to start out teaching beginning rubyists everything all at once. It was more to point out how important the mindset of each is. That's the mindset that you want to reach. And I'm not sure that teaching a construct that you'll never end up using is helpful. I think it just creates a mental construct that you'll have to overcome at a later stage. I don't think .each is so much harder to learn that it justifies getting a beginner in the wrong mindset. Though to be fair I've only ever explained it to people who've already known some programming, so there is a possibility that I'm underestimating the difficulty of teaching it. In any event, I thought the essay was totally worth the read even if I didn't agree with all of it. Thank you for it.
  - edwinnathaniel 14y ago
    2 keywords: - First loop programming construct - Beginner Exhale. Inhale. Now back to the blog post and see how many constructs to understand .each correctly vs "just accept it for now that this is how it should work, we'll come back later". Have you ever read such books? the ones with "we'll come back to it later".
  - wging 14y ago
    >I'm not sure that teaching a construct that you'll never end up using is helpful. But that was precisely Zed's point! You will certainly end up using it, though you may never use it in Ruby. .each is not transferable, and for-loops are. Zed's teaching Ruby as an introduction to programming, not just to Ruby in itself.
    - icebraining 14y ago
      each is definitively transferable for many languages. Javascript has Array.map(), which is almost the same: var numbers = [1, 4, 9]; var roots = numbers.map(Math.sqrt); /* roots is now [1, 2, 3], numbers is still [1, 4, 9] */ C# has IEnumerable.Select(): IEnumerable<int> squares = Enumerable.Range(1, 10).Select(x => x * x); /* squares is [1, 4, 9, 16, ...] */ Python has map(), which isn't OOP but accomplishes mostly the same: names = ["mary", "john"] caps = map(lambda name: name.upper(), names)
- warmfuzzykitten 14y ago
  I'm guessing Zed first learned to program using for loops so they look "natural" and easier for beginners to learn than functional callbacks. That seems like a testable proposition, but I'm guessing it isn't so. There aren't too many situations in life outside programming and racing where people go around in circles to get something done. Furthermore, the choice of print in the example begs the question. Are you teaching that imperative programming is natural and functional programming is only for "advanced" students? What are you going to teach the beginner when the goal is calculate the sum of the squares of a list of numbers?
  - JulianMorrison 14y ago
    FWIW I learned on BASIC. "GOTO" looks natural to me. It's also much closer to the machine. Structured programming is a prettification of test-and-jump, and you have to be able to see through it, to use it well. Functional programming, on the other hand, is a bit of a conceptual leap away from the metal. If you're mapping two functions over a stream of data how many loops is it? In a dumb language like Ruby, it will be as many as your map() calls. But in Haskell, it will fuse them into one loop doing two operations. And the thing with functional programming is, you're not supposed to care - except, you do have to. Generating an endless unresolved series of thunks in Haskell is a beginner mistake. But if you can't see through the functional list-flipping to the generation and consumption of callable heap objects in a test-and-jump cycle, you're going to be scratching your head. My answer would be to teach both assembler and FP, and step up and down simultaneously. Start on Excel and move to Haskell, while also starting on 6502 or some such toy assembler, and moving to C, and meet in the middle at Scheme.
  - thedufer 14y ago
    In a very real sense, imperative programming _is_ natural. Its much closer to how computers work. Whether this means that its an easier way to learn is up for debate. (For the record, I think it is easier for a majority of people, but that functional would be easier for a significant minority.) Your phrasing of that part just kind of bothered me. I think we already teach beginners that you calculate the sum of the squares of a list of numbers with a for loop. Actually, its a fairly common type of problem when you're learning about for loops. Maybe I'm missing your point?
- btilly 14y ago
  If you hate that last line, you must hate Unix pipelines as well. Because both accomplish similar things and are surprising to newcomers in a similar way.
- pacala 14y ago
  Right. Also, people should learn to swim by first dipping their tippy toes in a bathtub.
  - batista 14y ago
    Well, maybe they should.
- logical42 14y ago
  I kinda liked it actually. It's a linear sequence of simple operations, and there is an explicit connection between each successive operation (i.e. subsequent operatons are performed on the return value of the last operation). That's what I personally love about method chaining anyhow.. Functional composition with a structure that's not completely ad hoc is kinda nice.
- mjwalshe 14y ago
  Hear hear - some times clarity of code is far more important than showing of your leetness.
bmccormack 14y ago
When I was teaching myself how to program in VBA, I remember thinking "there's got to be some syntax to take a list of things and iterate over each of them." I was of course looking for a for loop (or for each). Without knowing to even google "for loop in VBA", it was a pretty big deal to finally discover, "Hey, programming languages have loops!" Later, after coding for a couple of years and picking up .NET, I eventually learned LINQ syntax and really started to appreciate the expressiveness of chaining methods together to iterate over collections. It was a nice addition to my tool box, but it still took some practice more me to grok it. If that had been my first exposure to loops, it likely would have been a stumbling block to my learning.
- mgkimsal 14y ago
  this is not a dig at you specifically, but more a lament about the basics of computing, and what's been lost. 30 years ago, I got a computer, and it came with this: http://www.worldofspectrum.org/ZX81BasicProgramming/ http://www.worldofspectrum.org/ZX81BasicProgramming/ Chapter 12 was 'looping'. I'm not claiming I was some programming genius, but to have been given a computer with a manual that, in < 100 pages spelled out the basic constructs of programming logic... that was magical. And useful. And empowering. I know we've all got the google at our fingertips today, but I suspect that many people don't even know how to express what they want to do in basic enough terms to search - thedailywtf has examples of that (sadly). I don't know if there's a way to reverse this, but it struck me that we've definitely lost something (or perhaps 'we' never all had it) when you state: 'Without knowing to even google "for loop in VBA"'. :/

zedshaw 14y ago

You are right, and once again I am not against using functional programming, OOP, message passing, or any of the things I mention about .each. I'm against using .each as a first looping construct. In fact, go look at your supposedly better last line of code and tell me if you think a newbie would even begin to comprehend that? Hell I'm a programming veteran and Ruby veteran and I want to metaphorically punch you in the gonads for that line of code.

cantankerous 14y ago
This is a good point. To play a little off your blog post, a person new to Ruby could view the second line of code more as an idiomatic expression (which it's not really, but it can have the appearance of being one) in that it doesn't make obvious logical sense and is harder to translate to a more familiar language...giving a "raising ravens" (Spanish) vs. "can of worms" (English) scenario. I think it'd be kinda cool if one could develop sort of a "ruby-normal-form" that could take some ruby expressions and translate them into a more normalized form using things like for-loops, etc....granted normalizing a lot of ruby code might be hard, intractable, or maybe even impossible.
- philwelch 14y ago
  If it threw in explicit returns at the end of each method and added back in all the optional parentheses, you'd be close to the average "Ruby code written by people who don't know Ruby that well" codebases you see in the wild so often.
rauljara 14y ago
To clarify, I don't think my original post implied that you were against teaching people how to learn each. Nor do I want to start out teaching beginning rubyists everything all at once. It was more to point out how important the mindset of each is. That's the mindset that you want to reach. And I'm not sure that teaching a construct that you'll never end up using is helpful. I think it just creates a mental construct that you'll have to overcome at a later stage. I don't think .each is so much harder to learn that it justifies getting a beginner in the wrong mindset. Though to be fair I've only ever explained it to people who've already known some programming, so there is a possibility that I'm underestimating the difficulty of teaching it. In any event, I thought the essay was totally worth the read even if I didn't agree with all of it. Thank you for it.
- edwinnathaniel 14y ago
  2 keywords: - First loop programming construct - Beginner Exhale. Inhale. Now back to the blog post and see how many constructs to understand .each correctly vs "just accept it for now that this is how it should work, we'll come back later". Have you ever read such books? the ones with "we'll come back to it later".
- wging 14y ago
  >I'm not sure that teaching a construct that you'll never end up using is helpful. But that was precisely Zed's point! You will certainly end up using it, though you may never use it in Ruby. .each is not transferable, and for-loops are. Zed's teaching Ruby as an introduction to programming, not just to Ruby in itself.
  - icebraining 14y ago
    each is definitively transferable for many languages. Javascript has Array.map(), which is almost the same: var numbers = [1, 4, 9]; var roots = numbers.map(Math.sqrt); /* roots is now [1, 2, 3], numbers is still [1, 4, 9] */ C# has IEnumerable.Select(): IEnumerable<int> squares = Enumerable.Range(1, 10).Select(x => x * x); /* squares is [1, 4, 9, 16, ...] */ Python has map(), which isn't OOP but accomplishes mostly the same: names = ["mary", "john"] caps = map(lambda name: name.upper(), names)
warmfuzzykitten 14y ago
I'm guessing Zed first learned to program using for loops so they look "natural" and easier for beginners to learn than functional callbacks. That seems like a testable proposition, but I'm guessing it isn't so. There aren't too many situations in life outside programming and racing where people go around in circles to get something done. Furthermore, the choice of print in the example begs the question. Are you teaching that imperative programming is natural and functional programming is only for "advanced" students? What are you going to teach the beginner when the goal is calculate the sum of the squares of a list of numbers?
- JulianMorrison 14y ago
  FWIW I learned on BASIC. "GOTO" looks natural to me. It's also much closer to the machine. Structured programming is a prettification of test-and-jump, and you have to be able to see through it, to use it well. Functional programming, on the other hand, is a bit of a conceptual leap away from the metal. If you're mapping two functions over a stream of data how many loops is it? In a dumb language like Ruby, it will be as many as your map() calls. But in Haskell, it will fuse them into one loop doing two operations. And the thing with functional programming is, you're not supposed to care - except, you do have to. Generating an endless unresolved series of thunks in Haskell is a beginner mistake. But if you can't see through the functional list-flipping to the generation and consumption of callable heap objects in a test-and-jump cycle, you're going to be scratching your head. My answer would be to teach both assembler and FP, and step up and down simultaneously. Start on Excel and move to Haskell, while also starting on 6502 or some such toy assembler, and moving to C, and meet in the middle at Scheme.
- thedufer 14y ago
  In a very real sense, imperative programming _is_ natural. Its much closer to how computers work. Whether this means that its an easier way to learn is up for debate. (For the record, I think it is easier for a majority of people, but that functional would be easier for a significant minority.) Your phrasing of that part just kind of bothered me. I think we already teach beginners that you calculate the sum of the squares of a list of numbers with a for loop. Actually, its a fairly common type of problem when you're learning about for loops. Maybe I'm missing your point?
btilly 14y ago
If you hate that last line, you must hate Unix pipelines as well. Because both accomplish similar things and are surprising to newcomers in a similar way.
pacala 14y ago
Right. Also, people should learn to swim by first dipping their tippy toes in a bathtub.
- batista 14y ago
  Well, maybe they should.
logical42 14y ago
I kinda liked it actually. It's a linear sequence of simple operations, and there is an explicit connection between each successive operation (i.e. subsequent operatons are performed on the return value of the last operation). That's what I personally love about method chaining anyhow.. Functional composition with a structure that's not completely ad hoc is kinda nice.
mjwalshe 14y ago
Hear hear - some times clarity of code is far more important than showing of your leetness.

bmccormack 14y ago

When I was teaching myself how to program in VBA, I remember thinking "there's got to be some syntax to take a list of things and iterate over each of them." I was of course looking for a for loop (or for each). Without knowing to even google "for loop in VBA", it was a pretty big deal to finally discover, "Hey, programming languages have loops!" Later, after coding for a couple of years and picking up .NET, I eventually learned LINQ syntax and really started to appreciate the expressiveness of chaining methods together to iterate over collections. It was a nice addition to my tool box, but it still took some practice more me to grok it. If that had been my first exposure to loops, it likely would have been a stumbling block to my learning.

mgkimsal 14y ago
this is not a dig at you specifically, but more a lament about the basics of computing, and what's been lost. 30 years ago, I got a computer, and it came with this: http://www.worldofspectrum.org/ZX81BasicProgramming/ http://www.worldofspectrum.org/ZX81BasicProgramming/ Chapter 12 was 'looping'. I'm not claiming I was some programming genius, but to have been given a computer with a manual that, in < 100 pages spelled out the basic constructs of programming logic... that was magical. And useful. And empowering. I know we've all got the google at our fingertips today, but I suspect that many people don't even know how to express what they want to do in basic enough terms to search - thedailywtf has examples of that (sadly). I don't know if there's a way to reverse this, but it struck me that we've definitely lost something (or perhaps 'we' never all had it) when you state: 'Without knowing to even google "for loop in VBA"'. :/