Some problems are better expressed in paradigms other than OOP. One of the beautiful things about Ruby is that you can use OOP or other paradigms on a case-by-case basis in accordance with what's best for the problem at hand. This article seems to miss the elegance of that.
Design patterns and OOP have their place, but this article adheres to them too dogmatically for my taste. It reminds me a little of this:
When I first started programming, I wanted a set of rules which, if followed strictly, would always guide me towards the perfect architecture. I've since learned that such a set of rules doesn't exist. Instead, we have to rely on our experience and insight to tell us which architecture will solve a given problem elegantly, and which will shoot us in the foot.
The OOP absolutists seem to be looking for that same El Dorado I once wanted. Ostensibly, design patterns promise us programming bliss through tried-and-true, universally applicable architectures. But they don't. Oftentimes, they just give you more lines of code than you really need.
It sounds like I'm dumping on OOP and design patterns, but I'm not. Like I said, there are plenty of perfectly good applications for them. My point is that it takes a bit of that aforementioned experience and insight to recognize those instances when they're appropriate. Otherwise you're just painting by numbers.
I stopped taking this post seriously when I got to "objects > functions" (at least in Ruby). I think it may be an elaborate gag.
All I can say is, if I worked in a Rails shop and checked some code in that used a helper to generate the A-Z index of a collection of models, and my boss told me, "no, you need to move that code to app/presenters/as_dictionary.rb, because that's where I've been putting my code that presents our data as_numbered_lists and as_abbreviated_snippets and as_random_selectons; it's called the Presenter pattern and we use it", I'd look for new projects.
Also, "structured programming" isn't "Programming 1.0" to "object oriented programming"'s "Programming 2.0". That is not how it works, Steve.
And if you'd rather cowboy up some code than stick with the abstractions your team is already using, I'd be glad you left the project.
I'm not defending these exact examples or anything, but come on. Any kid out of school can toss some code into a project that just works. It takes some discipline to write reusable code that people know where to look for later.
It's nice that Steve and others want to make Ruby on Rails applications better and faster.
But this post should have been the original blog post. You can't get frustrated by your audience "not getting it" if you use terrible examples or if you're lying to simplify.
This was a good explanation on the way to use presenters. The original one was not. I still don't plan to run out and use presenters everywhere because the payoff simply isn't there for most of the apps I write.
My bigger concern is that, like with most things in Ruby, a certain percentage of folks are going to just run wild with an idea, and even the simplest application is going to have a bunch of presenters in it just because someone said it was "the right way".
It's good to explain the real "why" with these concepts. What are the benefits, the drawbacks, and what will I be able to do that I couldn't do before? So I think this followup does a great job of that.
Your points are cogent, however blogs are more like conversations than books. With a book, you iterate a few times with your editor(s), you pass drafts around, and hopefully discover which examples aren’t clear before you publish. Everything else must wait for the second edition.
With a blog post, you can revise the original based on feedback, but the odds are that none of the people who read it the first time will see the revision. A follow-up post is the best way to expand/expound/correct yourself.
I agree that the first post could have been even better, but given the first post being what it was, putting out a second post seems like the right thing to do.
I agree, the original piece was a decent explanation of how to refactor some helper type code into a more Presenter like model. But he completely skipped out on the question of why it's a useful thing, and when it's a good fit. If that post had been by DHH or another Rails core member, we'd see it instantly picked up into the current cargo-cult trend of the month.
That said, I do appreciate Steve's work on finding ways outside of "the one true path" to simplify Ruby code, and hope he'll continue writing these sorts of things going forward. If nothing else, the discussion surrounding the technique and it's alternatives is extremely worthwhile.
" Why is it in Ruby that everything is an object, even integers, yet as soon as we need to format a date, we all turn into Dijkstra and bust out structured programming?"
" ... functions don’t provide a sufficient amount of power to tackle hard problems."
" objects > functions"
Why start an otherwise well written post with such trollish statements?
There's a lot more substance in the following paragraphs but instead everyone is focusing on those.
One of the things that has kept me away from the Ruby community is the way it simply takes as an axiom that OO === good; if it is OO it is good, if it is not OO it is bad. Re-read that and look at how many of his arguments are "X is not an object", with little further discussion of how that actually hurts you, just, "It's not OO" so apparently that concludes the argument that it is bad. (The class method comment links off to someone else who still comes down to a great degree to it not being "objects" properly. Yes, they may be overused, but pray tell what instance information the "sine" function takes? Oh, sorry, sine object.)
Your homework is to spend three months with Haskell learning idiomatic Haskell. Yes, it's not OO. Suck it up. You won't truly understand OO until you also understand not-OO.
Steve states: "objects > functions. At least in the context of getting stuff done in Ruby".
I completely agree that one should write idiomatic code. When you write Haskell, you write idiomatic Haskell. When you write Ruby, you should write idiomatic Ruby. Objects are idiomatic Ruby.
That statement is almost the opposite of true. The GoF patterns were invented to paper over the inadequacies of Java and C++ and make them behave more like languages like Ruby and Python.
I think Norvig's presentation should be required reading in order to obtain your Ruby or Python programming license:
To rephrase the quote: Design patterns can be good in the appropriate situations, but Java's heavy use of them has soured people on them altogether.
They're often used ad absurdum in Java, to the extent where even in situations you don't need the complex functionality they support, you're stuck using them (often incorrectly because you don't need them) and they become a burden instead of useful.
Design Patterns are names given to ways of doing things, so that programmers can talk about the same things.
Any time you forget that, or start using phrases like 'Anti-Pattern', you lose (unless you're an expensive consultant, then you're about to get paid!). This appears to be the current forefront of Java development methodology (based purely on what I've read on HN).
Actually, come to think of it, Djikstra [sic] wouldn’t even write any code, because it’s beneath him, but you get the idea.
This is ridiculous. Of course Dijkstra wrote code. He authored the first implementation of an ALGOL 60 compiler, if I'm not mistaken.
Though, technically for Dijkstra writing code was a bit beneath him, as he preferred deriving it using his Guarded Command Language. But the point stands. Dijkstra may have been a bit of a dick, but there's no need to libel a dead man.
I think that he's referring to a quote from Dijkstra: "Computer science is no more about computers than astronomy is about telescopes." [1] Said another way: it's just a joke :-).
His software, of which these are two examples, have low enough error rates that anybody who seriously evaluates today's software would do a double-take.
[+] [-] jarrett|14 years ago|reply
Design patterns and OOP have their place, but this article adheres to them too dogmatically for my taste. It reminds me a little of this:
http://steve-yegge.blogspot.com/2006/03/execution-in-kingdom...
When I first started programming, I wanted a set of rules which, if followed strictly, would always guide me towards the perfect architecture. I've since learned that such a set of rules doesn't exist. Instead, we have to rely on our experience and insight to tell us which architecture will solve a given problem elegantly, and which will shoot us in the foot.
The OOP absolutists seem to be looking for that same El Dorado I once wanted. Ostensibly, design patterns promise us programming bliss through tried-and-true, universally applicable architectures. But they don't. Oftentimes, they just give you more lines of code than you really need.
It sounds like I'm dumping on OOP and design patterns, but I'm not. Like I said, there are plenty of perfectly good applications for them. My point is that it takes a bit of that aforementioned experience and insight to recognize those instances when they're appropriate. Otherwise you're just painting by numbers.
[+] [-] bphogan|14 years ago|reply
[+] [-] tptacek|14 years ago|reply
All I can say is, if I worked in a Rails shop and checked some code in that used a helper to generate the A-Z index of a collection of models, and my boss told me, "no, you need to move that code to app/presenters/as_dictionary.rb, because that's where I've been putting my code that presents our data as_numbered_lists and as_abbreviated_snippets and as_random_selectons; it's called the Presenter pattern and we use it", I'd look for new projects.
Also, "structured programming" isn't "Programming 1.0" to "object oriented programming"'s "Programming 2.0". That is not how it works, Steve.
[+] [-] exogen|14 years ago|reply
I'm not defending these exact examples or anything, but come on. Any kid out of school can toss some code into a project that just works. It takes some discipline to write reusable code that people know where to look for later.
[+] [-] bphogan|14 years ago|reply
But this post should have been the original blog post. You can't get frustrated by your audience "not getting it" if you use terrible examples or if you're lying to simplify.
This was a good explanation on the way to use presenters. The original one was not. I still don't plan to run out and use presenters everywhere because the payoff simply isn't there for most of the apps I write.
My bigger concern is that, like with most things in Ruby, a certain percentage of folks are going to just run wild with an idea, and even the simplest application is going to have a bunch of presenters in it just because someone said it was "the right way".
It's good to explain the real "why" with these concepts. What are the benefits, the drawbacks, and what will I be able to do that I couldn't do before? So I think this followup does a great job of that.
[+] [-] raganwald|14 years ago|reply
With a blog post, you can revise the original based on feedback, but the odds are that none of the people who read it the first time will see the revision. A follow-up post is the best way to expand/expound/correct yourself.
I agree that the first post could have been even better, but given the first post being what it was, putting out a second post seems like the right thing to do.
[+] [-] tannerburson|14 years ago|reply
That said, I do appreciate Steve's work on finding ways outside of "the one true path" to simplify Ruby code, and hope he'll continue writing these sorts of things going forward. If nothing else, the discussion surrounding the technique and it's alternatives is extremely worthwhile.
[+] [-] rlander|14 years ago|reply
" ... functions don’t provide a sufficient amount of power to tackle hard problems."
" objects > functions"
Why start an otherwise well written post with such trollish statements?
There's a lot more substance in the following paragraphs but instead everyone is focusing on those.
[+] [-] jerf|14 years ago|reply
Your homework is to spend three months with Haskell learning idiomatic Haskell. Yes, it's not OO. Suck it up. You won't truly understand OO until you also understand not-OO.
[+] [-] shepmaster|14 years ago|reply
I completely agree that one should write idiomatic code. When you write Haskell, you write idiomatic Haskell. When you write Ruby, you should write idiomatic Ruby. Objects are idiomatic Ruby.
[+] [-] ww520|14 years ago|reply
[+] [-] tptacek|14 years ago|reply
I think Norvig's presentation should be required reading in order to obtain your Ruby or Python programming license:
http://norvig.com/design-patterns/
Think of all the countless lives that could be saved.
[+] [-] cbs|14 years ago|reply
They're often used ad absurdum in Java, to the extent where even in situations you don't need the complex functionality they support, you're stuck using them (often incorrectly because you don't need them) and they become a burden instead of useful.
[+] [-] peteretep|14 years ago|reply
Any time you forget that, or start using phrases like 'Anti-Pattern', you lose (unless you're an expensive consultant, then you're about to get paid!). This appears to be the current forefront of Java development methodology (based purely on what I've read on HN).
[+] [-] adgar|14 years ago|reply
This is ridiculous. Of course Dijkstra wrote code. He authored the first implementation of an ALGOL 60 compiler, if I'm not mistaken.
Though, technically for Dijkstra writing code was a bit beneath him, as he preferred deriving it using his Guarded Command Language. But the point stands. Dijkstra may have been a bit of a dick, but there's no need to libel a dead man.
[+] [-] shepmaster|14 years ago|reply
[1] http://thinkexist.com/quotation/computer_science_is_no_more_...
[+] [-] wglb|14 years ago|reply
His software, of which these are two examples, have low enough error rates that anybody who seriously evaluates today's software would do a double-take.