Anonymous asks, with dollars:

More about programming languages!

Well then!

I’ve written before about what I think objects are: state and behavior, which in practice mostly means method calls.

I suspect that the popular impression of what objects are, and also how they should work, comes from whatever C++ and Java happen to do. From that point of view, the whole post above is probably nonsense. If the baseline notion of “object” is a rigid definition woven tightly into the design of two massively popular languages, then it doesn’t even make sense to talk about what “object” should mean — it does mean the features of those languages, and cannot possibly mean anything else.

I think that’s a shame! It piles a lot of baggage onto a fairly simple idea. Polymorphism, for example, has nothing to do with objects — it’s an escape hatch for static type systems. Inheritance isn’t the only way to reuse code between objects, but it’s the easiest and fastest one, so it’s what we get. Frankly, it’s much closer to a speed tradeoff than a fundamental part of the concept.

We could do with more experimentation around how objects work, but that’s impossible in the languages most commonly thought of as object-oriented.

Here, then, is a (very) brief run through the inner workings of objects in four very dynamic languages. I don’t think I really appreciated objects until I’d spent some time with Python, and I hope this can help someone else whet their own appetite.

Ah, C. The best lingua franca we have… because we have no other lingua francas. Linguae franca. Surgeons general?

C is fairly old — 44 years, now! — and comes from a time when there were possibly more architectures than programming languages. It works well for what it is, and what it is is a relatively simple layer of indirection atop assembly.

Alas, the popularity of C has led to a number of programming languages’ taking significant cues from its design, and parts of its design are… slightly questionable. I’ve gone through some common features that probably should’ve stayed in C and my justification for saying so. The features are listed in rough order from (I hope) least to most controversial. The idea is that C fans will give up when I call it “weakly typed” and not even get to the part where I rag on braces. Wait, crap, I gave it away.

You may have noticed that I like comparing features across different languages. I hope you like it too, because I’m doing it again.

Sometimes, I lie awake at night thinking about programming languages.

That’s all the intro I’ve got here, sorry. I felt like writing about the switch statement for some reason.

…is, of course, naming.

Not just naming variables or new technologies. Oh no. We can’t even agree on names for basic concepts.

Creating a programming language is apparently all the rage these days, and it’s got me thinking about what I would really like to see in one. I’m starting to suspect the things I want are either impossible or mutually incompatible, so I’d better write them down and let smarter people tell me why I can’t have everything and also a pony.

I’m strongly influenced by my love of Python, my aversion to C and C++, my fascination with Rust, and the bits of Haskell I understand. I very recently read an overview of Nim, which is part of what got my juices flowing. Also I have a lot of fond memories of what Perl 6 could have been, so, fair warning.

This is a brain dump, not a linear narrative, so some of this might be mutually referential or causally reversed or even complete nonsense. Please pardon the dust.

Almost a year ago now, Jack Diederich gave a talk entitled “Stop Writing Classes“, in which he implores Python programmers to stop creating classes just for the hell of it, and specifically calls out the common pattern of a class with only a constructor/initializer and a single method—which should, of course, just be a function.

A few weeks ago, Armin Ronacher wrote a rebuttal entitled “Start Writing More Classes“, which argues that classes are essential for both writing extensible code and smoothing over crappy interfaces. (Hm. Now that I look at it again, if you read the post backwards, it almost sounds like he’s suggesting writing a class to smooth out the crappy interface you get from using too many classes…)

I’m having some trouble here, because I agree with both points of view. There must be a way to resolve this contradiction, a message that resonates with everyone.

I think I’ve found it.

Stop writing stupid classes.

It’s hard to get a feel for a new tool. Is it any good? Does it do anything I can’t already do? What’s the community like? Tough questions to answer without diving in and using it for a significant amount of time—and then you risk not liking the answers you get.

But fear not! I have discovered a new and brilliant way to discern the novel features of a tool, the vibrance of its community, and its range of users all at once. In mere minutes.

Look at its ten highest-voted questions on StackOverflow.

I’m totally serious. Watch.

Yelp had a hackathon a couple weeks ago. These affairs are mixed blessings for me: a fixed chunk of uninterrupted time to work on a single project is great, but I tend to have at least a dozen ideas that I want to do all at once, none of which can be reasonably “finished” in a scant 30 hours, and most of which are obscure enough that nobody can work on them with me.

For example, during this most recent event, I wrote a roguelike. In Rust.

Long-time readers may recall that I’ve attempted to write a roguelike before, in Python, but fell prey to architecture astronomy. This time would be different! Because I would only have 30 hours. Also because static typing limits my options, thus making it easier to overcome choice paralysis. (It’s a working theory.)

But first: a bunch of people have asked what I think of Rust, and now I’ve actually written something approaching a real program in it, so let’s start there.

Part of my Python FAQ.

How does @property work? Why does it call my __getattr__? What’s a “descriptor”?

(This article has been translated into Spanish (PDF, with some additions) by Jorge Amado Soria Ramirez — thanks!)

Preface

I’m cranky. I complain about a lot of things. There’s a lot in the world of technology I don’t like, and that’s really to be expected—programming is a hilariously young discipline, and none of us have the slightest clue what we’re doing. Combine with Sturgeon’s Law, and I have a lifetime’s worth of stuff to gripe about.

This is not the same. PHP is not merely awkward to use, or ill-suited for what I want, or suboptimal, or against my religion. I can tell you all manner of good things about languages I avoid, and all manner of bad things about languages I enjoy. Go on, ask! It makes for interesting conversation.

PHP is the lone exception. Virtually every feature in PHP is broken somehow. The language, the framework, the ecosystem, are all just bad. And I can’t even point out any single damning thing, because the damage is so systemic. Every time I try to compile a list of PHP gripes, I get stuck in this depth-first search discovering more and more appalling trivia. (Hence, fractal.)

PHP is an embarrassment, a blight upon my craft. It’s so broken, but so lauded by every empowered amateur who’s yet to learn anything else, as to be maddening. It has paltry few redeeming qualities and I would prefer to forget it exists at all.

But I’ve got to get this out of my system. So here goes, one last try.

An analogy

I just blurted this out to Mel to explain my frustration and she insisted that I reproduce it here.

I can’t even say what’s wrong with PHP, because— okay. Imagine you have uh, a toolbox. A set of tools. Looks okay, standard stuff in there.

You pull out a screwdriver, and you see it’s one of those weird tri-headed things. Okay, well, that’s not very useful to you, but you guess it comes in handy sometimes.

You pull out the hammer, but to your dismay, it has the claw part on both sides. Still serviceable though, I mean, you can hit nails with the middle of the head holding it sideways.

You pull out the pliers, but they don’t have those serrated surfaces; it’s flat and smooth. That’s less useful, but it still turns bolts well enough, so whatever.

And on you go. Everything in the box is kind of weird and quirky, but maybe not enough to make it completely worthless. And there’s no clear problem with the set as a whole; it still has all the tools.

Now imagine you meet millions of carpenters using this toolbox who tell you “well hey what’s the problem with these tools? They’re all I’ve ever used and they work fine!” And the carpenters show you the houses they’ve built, where every room is a pentagon and the roof is upside-down. And you knock on the front door and it just collapses inwards and they all yell at you for breaking their door.

That’s what’s wrong with PHP.

I’ve touched on this kind of thing before, but I just saw it come up again, and I think it’s worth its own post not buried in an avalanche of armchair psychology. Plus, I remembered that Blogofile does syntax highlighting.

Closures in a loop

If you’ve been linked here, you’ve probably complained that this doesn’t work as you expect:

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funcs = []
for i in range(4):
    def f():
        print i
    funcs.append(f)

for f in funcs:
    f()

The output will be 3, repeated four times. Gasp! Python is totally broken! It doesn’t support closures!

Well, no. Python supports closures all too well, and that’s causing the problem here. The issue is with scoping.