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Podcast 050


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Yegge: You know John Cage is the composer who pissed everyone off with his 4 minutes and 37 seconds composition which was a dude sitting at a piano for 4 minutes and 37 seconds.

Spolsky: 33.

Yegge: And not playing it, was it 33 ?

Spolsky: 4'33".

Yegge: Oh man, I'm 4 seconds out.

Spolsky: You just, well I think you might have your own new composition.

Yegge & Spolsky: <laughs>

Spolsky: Our guest today on the StackOverflow Podcast is Mr Steve Yegge.

Yegge: Howdy howdy.

Spolsky: Formerly of Amazon, and the Navy even before that, currently of Google in Kirkland where Michael and I are visiting. Jeff is on the line from Emeryville.

Atwood: Well actually El Cerrito but close, very close.




Yegge: It's foolish to, to, to try to ... I saw this dude, you know, hes not with us anymore and he left voluntarily, he was a good programmer, I mean people can get by with just basic V.I. But I mean the dude had, he was using not Vim, he was using V.I. Like Vi or whatever you call it, the old one. it was like Ed.

Spolsky: Ed. One comma three I <laughs>

Yegge: Exactly, and he, he didn't have any colors, he was using the green on black terminal theme you know, reminiscent of the old days. Even though, he just got out of college and probably didn't even know what he was doing, right, hadn't used a terminal before and he didn't even have paren matching turned on, right, he had no braces, and he was doing this like really deeply nested javascript and every time he'd make a change, you know, he'd like go in and he kept spelling it fuction instead of function, right.

<Joel cackles>

Yegge: And I'd watch over his shoulder and i'd be like "Dude, you spelled it fuction again". Right ...




Spolsky: Doesn't—isn't there a problem that ... I know that in the case of IntelliSense, at least, it's very very hard to do good IntelliSense if you don't know the type that something is—that the variable is pointing at.

Yegge: Well, it is hard, but I notice that you didn't say it's impossible, and that's—that's the correct word, because it's not impossible.

Spolsky: Mm-hmm.

Yegge: It is just hard. Google has a JavaScript compiler.

Spolsky: Right.

Yegge: I don't know if we talk about it or anything. I know we're planning on open sourcing it—we're working on it.

Spolsky: Is it—is it the same as the one in Chrome?

Yegge: I don't know—no, it's not. The one in Chrome is a VM.

Spolsky: OK.

Yegge: The one in Chrome actually interprets JavaScript. What we have is a compiler, that will—you know, it's the thing that crunches it down, so if you actually look at the JavaScript from, like, Maps, or, ... whatever, right, you know—Gmail...

Spolsky: Oh, OK.

Yegge: It's a very—You know, it's kind of obfuscated—and it's not obfuscated...

Spolsky: It's still JavaScript.

Yegge: It's still JavaScript, but what they've done is they've given all the variables very short names...

Spolsky: Right.

Yegge: ...they've taken all these shortcut—but it actually does a very very sophisticated analysis of the JavaScript, and we have our own internal type system that we've kind of developed, right, that's more or less modeled on the way JavaScript's type system is evolving through the ECMA stuff—I don't know if you guys have been following that, but...

Spolsky: Mm-hmm.

Yegge: So like, you can write typed JavaScript.

Spolsky: OK.

Yegge: So there's classes, and there's methods, and inheritance, and there's even to some extent, you know, parameterized types and things like that.

Spolsky: Do you have to declare the types?

Yegge: You don't have to—there's type inference.

Spolsky: OK.

Yegge: So, the more types that you declare, especially at key points where there's a little bit of purchase for the type inference engine...

Spolsky: Yeah. Yeah.

Yegge: ...the better...

Spolsky: Yeah.

Yegge: …and it'll tell you, "Oh gosh, I have no idea what's going on here", right?

Spolsky: Yeah.

Yegge: But it does—it's very smart. It actually knows about, like, union types, and so, like, if you have a function, like in JavaScript, that takes a number or string, and it just casts, you know, or does…

Spolsky: Yeah.

Yegge: …maybe it dispatches and does something different, you know?

Spolsky: Mm-hmm.

Yegge: ...because they don't have overloading, right? So what you do is you just look at your arguments and see what you got and then do some dispatch, right?

Spolsky: Mm-hmm.

Yegge: The type inference engine in JSCompiler will actually, like, figure out what all the possible things are that you do pass in, and create a union type for those, right?

Spolsky: <unintelligible>

Yegge: And none of this is ever surfaced in any sort of an IDE, or anything—it's just warnings or errors at build time, right?

Spolsky: So it can catch things faster.

Yegge: Yeah—but I mean, so it would be very nice if it could catch it as you typed it.

Spolsky: Mm-hmm.

Yegge: Right?

Spolsky: And plus, like, know what the type of that object is, so that... <overtalked>

Yegge: Absolutely. <overtalked> So that you could do—exactly—autocompletion, and things like that, right?

Spolsky: Yeah.

Yegge: Code navigation. So, the JavaScript approach that we've taken is, I think, a model for how we're going to do static analysis, and when I say "we", I mean the industry—how we want to do static analysis for languages like Perl and Python and Ruby and so on. In fact, the Python crowd here, when they what I had done internally, they were like "oh, we want that for Python in a big way." And so...

Spolsky: Mm-hmm.

Yegge: ...I'm like, well, yeah. We have to write a Python compiler, you know..

Spolsky: Mm-hmm.

Yegge:'s going to be some work. Because, the thing is, it's a very—it's a really sophisticated compiler. It does like 50 passes over the IR, and it does—it builds a, you know, control flow graph, and all that Dragon Book stuff, right?

Spolsky: Mm-hmm.

Yegge: And it's doing it with JavaScript.

Spolsky: Mm-hmm.

Yegge: And it's starting—it's starting off with very few types. I mean, it's the types that you give it, right, but I mean, like, you could potentially, I mean, I think, eventually we're going to be able to run it on third-party code, where all—the only types are, like, you know, literals, and functions—you know, there isn't a type system, right? But it can still infer kind of a lot of stuff there, right?

Spolsky: Yeah.

Yegge: So, like, anyways, so, again, it's hard, it's a lot of work, and it could be better, and so on, but I mean it's pretty good. And then with C++, and with Java, and any statically typed language, you have types.

Spolsky: Mm-hmm.

Yegge: So you have a lot of stuff for the IntelliJ...

Spolsky: Sure.

Yegge: ...IntelliSense stuff to work.

Spolsky: There's actually, I mean, if you open up—in the latest version of Visual Studio, if you open up an HTML file that has a bunch of random JavaScript pasted in there—the JavaScript will get syntax colored.

Yegge: Mm-hmm.

Spolsky: And IntelliSense will almost work, and it'll use all kinds of exhaustive methods...

Yegge: Yes.

Spolsky: try to guess what type things are.

Yegge: Yes.

Spolsky: Sometimes in ways that are maybe 95% accurate...

Yegge: And you know what?

Spolsky: <simultaneous> but not 100%...

Yegge: That's been my, sort of, core philosophy, is that if it's 95% accurate, then, you know, 5% of the time, you're going to be fixing it, you know...

Spolsky: Yeah.

Yegge: That's no worse than, like, the indentation, for JavaScript, or...

Spolsky: Ha.

Yegge: ...probably for C++, right? Every once in a while, it doesn't indent exactly the way you want, but as long as it's helping you...

Spolsky: Yep.

Yegge: You know, um...

Spolsky: A lot of times, when it's failing, it's cuing you off as to something that you did nonstandard that's...

Yegge: That's true.

Spolsky: Or possibly even wrong.

Yegge: It could—you're right, it's actually kind of an incentive for you to sort of code in a more transparent way.

Spolsky: Mm-hmm.

Yegge: Now, people who love to write obfuscated JavaScript, you know, will kind of sniff at that—go "Whoa, I want to use, you know, anonymous function callbacks nested inside of other closures that are passed along with them." Then you're like, "Fine."

Spolsky: Mm-hmm.

Yegge: "Your tool won't know what the hell you're doing."

Spolsky: Mm-hmm. <laughs>

Yegge: And that's your choice, right?

Spolsky: Right.


[76:26 ends]

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Last Modified: 5/11/2013 6:13 PM

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