Episode 309: Default Construction & CppCon 2026 with Jason Turner の全文書き起こし

again I think is a poor term to use, because actually it's not needed. 00:04:56.319 --> 00:05:06.480 It's not needed, I don't think, to define regular, and it's not really needed to even implement the standard library for the most part, you know. 00:05:06.480 --> 00:05:22.240 So so supplying default constructibility because we think that's what's needed for the code, actually, if we think about containers, it's only vector resize and and square bracket operator on on the map types that require default constructability. 00:05:22.240 --> 00:05:25.120 There are no other functions on containers that don't I I think. 00:05:25.439 --> 00:05:26.160 What were those two? 00:05:26.160 --> 00:05:29.120 The second one was the square brackets on map types, the first one was. 00:05:29.439 --> 00:05:30.879 Yeah, the indexing operator. 00:05:30.879 --> 00:05:34.160 And that arguably is a poorly designed API, right? 00:05:34.160 --> 00:05:35.680 Indexing into a map in C. 00:05:35.680 --> 00:05:38.800 Default constructs the object if it wasn't there. 00:05:39.120 --> 00:05:41.920 I just I just watched, it was it was on my list for a long time. 00:05:41.920 --> 00:05:46.079 There's a is it two-hour video called The Worst Language Ever? 00:05:46.480 --> 00:05:47.600 Oh, I've seen the title. 00:05:47.600 --> 00:05:48.800 I haven't watched the video, yeah. 00:05:49.040 --> 00:05:51.279 Yeah, it's a clickbaity title. 00:05:51.279 --> 00:05:59.759 It's about C, but really it's like a master class in like, you know, becoming a language expert and finding all the different things. 00:05:59.759 --> 00:06:09.120 And that's in the first ten minutes, I think it talks about that being one of the biggest kind of warts of the container types is is that kind of behavior. 00:06:09.120 --> 00:06:15.839 And it it puts it up against Python and Java and a bunch of other languages, and it's like no other language does this because it's absurd. 00:06:15.839 --> 00:06:17.839 Like it's not at all what you expect. 00:06:18.240 --> 00:06:26.800 Default construction, I should say I'd like to stop using the term default construction and and indeed say non-initializing construction versus nullery construction, right? 00:06:26.800 --> 00:06:43.360 So non-initializing construction, which is what the language applies to built-in types, basically, that that leads us down the route of, oh, you know, we have to deal with it historically, so now we have erroneous behavior, for example, for reading from non-initialized built-in types. 00:06:43.360 --> 00:06:59.199 It also kind of flies in the face of, you know, one of the original things at C, one of the original kind of selling points, if you like, of C over C is that we don't have to declare all our automatic variables up front only to assign them later. 00:06:59.199 --> 00:07:02.319 We can wait till we need the variable to declare it. 00:07:02.319 --> 00:07:05.279 And at that point we know how to initialize it, presumably. 00:07:05.279 --> 00:07:10.800 And you know, this is certainly a best practice I know that Jason espouses, and then you can mark it const and all those good things, right? 00:07:10.800 --> 00:07:15.279 And and Connor, I know you've talked about the initialize, then modify anti-pattern. 00:07:15.279 --> 00:07:23.199 You know, so the idea of non-initializing construction just is anathema to to this kind of best practices worldview. 00:07:23.360 --> 00:07:26.319 Yeah, I'm not gonna disagree with you for sure. 00:07:26.319 --> 00:07:29.680 And then there's fallback solutions if you really need them. 00:07:29.680 --> 00:07:38.480 Like you can make an optional of the thing and then uh fill it in later, which I don't love optional, but that is a good use case for optional, right? 00:07:38.720 --> 00:07:41.519 Yeah, it's it's the major use case I have, I think. 00:07:41.519 --> 00:07:42.800 Deferred construction. 00:07:43.120 --> 00:07:46.879 I just I feel like I just want to say out loud to anyone who just heard me say that. 00:07:46.879 --> 00:07:50.480 Still try to figure out if you don't need optional first, right? 00:07:50.480 --> 00:07:53.839 Don't just be like, oh, I'll just use optional here because I don't have a plan. 00:07:53.839 --> 00:07:54.959 You know, don't do that. 00:07:55.920 --> 00:07:57.920 What does I I don't use these algorithms? 00:07:57.920 --> 00:07:59.199 Or or sorry, go ahead, Jason. 00:07:59.199 --> 00:08:03.600 I was gonna say, I I don't use these algorithms, but I know that they were added. 00:08:03.600 --> 00:08:07.519 The uninitialized underscore operations. 00:08:07.519 --> 00:08:11.680 What does yeah, what does your commentary here, Ben, say about those? 00:08:11.680 --> 00:08:16.000 Like I'm this is a more of like because I like Oh, you're talking about the algorithms in memory. 00:08:16.079 --> 00:08:19.439 I think it's copy uninitialized and move uninitialized, is that right? 00:08:19.680 --> 00:08:40.240 Yeah, but I think they might have even come up I've never looked at I've I've seen them maybe even in Thrust or some other libraries, and and they are like for I think performance reasons, but like when I hear potentially like an argument for do we do we even obviously they're not gonna do this to C ⁇ , but we're talking hypothetically here, you know, do we even need quote unquote, you know, default construction? 00:08:40.240 --> 00:08:48.480 Like, does that I mean what does the existence of these uninitialized algorithms or operations like mean in in this kind of context? 00:08:48.639 --> 00:08:49.519 Like I don't have the answer. 00:08:49.519 --> 00:08:51.679 I haven't used them a whole lot. 00:08:51.679 --> 00:09:01.519 I I tend to think something is telling me, I'm remember if I'm remembering right, they are often used in the implementation of types like vector. 00:09:01.519 --> 00:09:11.120 And they are for things like I I I ha I yeah, I I need to I need to do things which involve micromanagement of lifetimes. 00:09:11.360 -->

00:09:11.600 Yeah. 00:09:11.600 --> 00:09:13.360 Constexpr in 26. 00:09:13.360 --> 00:09:14.639 Looking up the details here. 00:09:14.639 --> 00:09:16.320 I've never done I've never used them. 00:09:16.320 --> 00:09:20.480 This is like and this is officially going on a list for an upcoming C weekly episode. 00:09:20.480 --> 00:09:21.519 Perfect. 00:09:21.759 --> 00:09:22.000 Yeah. 00:09:22.000 --> 00:09:29.600 I I've I've only ever used them in things like implementing like my own containers, my own vector, for example. 00:09:30.080 --> 00:09:34.320 It's clearly not necessary for the constexpr implementation of vector. 00:09:34.320 --> 00:09:37.759 Otherwise, it would have been constexpr in C20. 00:09:37.759 --> 00:09:40.879 That's how these things tend to fall out in the standard. 00:09:40.879 --> 00:09:41.919 So I am curious. 00:09:42.240 --> 00:10:01.600 Yeah, I just I Googled uninitialized on CPP reference, and the set that comes up when you Google or Google that search that, is std uninitialized copy, uninitialized fill, uninitialized move, uninitialized value construct, unitialized default construct, and initi uninitialized construct use and then there's ranges versions of those also, it seems. 00:10:01.600 --> 00:10:07.039 Yeah, and they're they're all defined in memory, not algorithm, although it says specialized memory algorithm. 00:10:07.039 --> 00:10:17.360 Page and confusingly puts it under the algorithm, or it doesn't put it under, but to the left of the specialized memory algorithms is the algorithm library. 00:10:17.679 --> 00:10:25.840 So I'm gonna think of these things as specialist tools for managing lifetime in things like containers, like we said. 00:10:25.840 --> 00:10:35.039 I think if you find yourself using these in application quote quote application code, then then maybe take a step back and look at encapsulating it in. 00:10:35.519 --> 00:10:35.679 Right. 00:10:35.679 --> 00:10:38.480 No raw uninitialized algorithms. 00:10:38.480 --> 00:10:41.679 Not as catchy as uh Sean's no raw loops, but hey. 00:10:41.919 --> 00:10:47.440 Yeah, the the idea of uninitialized or non-initializing construction, like for ints, right? 00:10:47.440 --> 00:11:05.759 So if we think about this more, I think I was thinking about this like so and I and I looked inside elements of programming and it defines regular types in chapter 1.5, and it doesn't actually say that your default construction is required, it says construction is required, and then it goes on to say that default construction is when you have no argument. 00:11:05.759 --> 00:11:12.879 Uh but it's not necessarily true, I think, for a consistent view of of regularity that we require default construction. 00:11:12.879 --> 00:11:22.080 The the one axiom, if you like, of regularity is that if you copy a T, then the A and the B should compare equal after the copy. 00:11:22.080 --> 00:11:22.480 Right? 00:11:22.480 --> 00:11:26.159 That's that's the axiom that links copying and equality.

00:11:26.159 --> 00:11:29.519 And it and it presupposes that you have a T available. 00:11:29.519 --> 00:11:34.639 How that T was constructed, the we don't really care at that point, right? 00:11:34.639 --> 00:11:44.559 And it may be also be true that some of the containers in their internals from time to time require nullery construction. 00:11:44.559 --> 00:11:45.039 Right. 00:11:45.039 --> 00:11:48.799 And that I'm not I'm not using deliberately not saying default construction. 00:11:48.799 --> 00:11:54.559 But if if we if we just say int x with with no initializer, right? 00:11:54.559 --> 00:12:00.000 So that the storage is there, the int is it alive? 00:12:00.000 --> 00:12:04.799 I think it's alive, but it has but but it's partially formed. 00:12:04.799 --> 00:12:11.200 And these are also the words of elements of programming, it's partially formed, which is to say that you can either destroy it or assign to it. 00:12:11.679 --> 00:12:12.240 And you cannot read it. 00:12:12.559 --> 00:12:13.600 What it says in EOP. 00:12:13.600 --> 00:12:14.639 You cannot read it. 00:12:14.639 --> 00:12:17.600 That's erroneous behavior from from 26 onwards, right? 00:12:17.600 --> 00:12:27.200 Um Well, you know, part of me wants to ask, what what is the point of constructing an object that cannot be in any meaningful way used? 00:12:27.200 --> 00:12:35.440 It it seems to me like if the the the fact of the matter is like built-in types do not have class invariant, right? 00:12:35.440 --> 00:12:38.480 They're not class types, we don't think of them as having class invariants. 00:12:38.480 --> 00:12:39.679 But maybe we should. 00:12:39.679 --> 00:12:47.440 And if we were to do that, then we would naturally think, well, you know, if I'm constructing an int and not initializing it, then that's upholding none of its invariants. 00:12:47.440 --> 00:12:49.440 It can't be used in any meaningful way. 00:12:49.440 --> 00:12:54.480 And that is part of its interface, and therefore that is you know, I expect after I construct an int that I can use it. 00:12:54.720 --> 00:12:56.320 Yeah, that's a fair argument. 00:12:56.559 --> 00:12:58.480 Anyway, that's my soapbox. 00:12:58.799 --> 00:12:59.519 Yeah, no. 00:12:59.519 --> 00:13:09.120 And I think adjacent to your soapbox is I've made a point of demonstrating this in a few talks, and I bring it up with students whenever it makes sense to. 00:13:09.120 --> 00:13:15.519 And it's it was one of the points that I end up making at the very end of this rule of n talk. 00:13:15.519 --> 00:13:16.639 Well, I don't whatever. 00:13:16.639 --> 00:13:17.919 I make the point somewhere in the talk. 00:13:17.919 --> 00:13:18.960 Depends on the version. 00:13:18.960 --> 00:13:33.759 If the thing does not have a default constructor, like if you must provide something to construct the thing, I have come to the conclusion personally that this object should not be movable under most cases. 00:13:33.759 --> 00:13:38.159 Because the now, so can I

ask a clarifying question? 00:13:38.320 --> 00:13:40.480 Do you mean it should only be copiable? 00:13:40.799 --> 00:13:41.279 Yes. 00:13:41.279 --> 00:13:41.840 Okay. 00:13:41.840 --> 00:13:43.120 Potentially, yeah. 00:13:43.120 --> 00:13:44.799 Copyable or I mean, yeah. 00:13:44.799 --> 00:13:48.159 So I made what I did was I was trying to illustrate the point. 00:13:48.159 --> 00:13:55.360 So I made a simple ring buffer type, and it's probably broken by the standards of many people's ring buffer notions, whatever. 00:13:55.360 --> 00:14:01.679 But it requires a size because it needs to know how much storage to create, right? 00:14:01.679 --> 00:14:09.120 Now, me in an alternate universe would have made that size a uh template parameter, but I didn't want to for the sake of this example. 00:14:09.120 --> 00:14:10.480 I made it a runtime parameter. 00:14:10.480 --> 00:14:12.159 So it you must provide a size. 00:14:12.159 --> 00:14:19.360 If you provide a size of zero, it's gonna allocate an array of zero internally, but it's still a valid pointer, valid storage, right? 00:14:19.360 --> 00:14:25.679 So, or actually I might have even put a contract on it saying that the size is greater than zero because I was just trying to illustrate a bunch of different points. 00:14:25.679 --> 00:14:29.120 But regardless, I have something that holds a pointer to a thing. 00:14:29.120 --> 00:14:35.120 Think like unique pointer, but think a unique pointer that cannot be constructed with a null pointer. 00:14:35.120 --> 00:14:40.000 Like that is an invalid use case, a unique pointer that must be constructed with a valid pointer. 00:14:40.000 --> 00:14:51.120 If you move out from this unique pointer, the thing that is left behind, the moved from object, is now in effectively an unusable state, like you're talking about. 00:14:51.120 --> 00:14:56.879 Like I can, well, unique pointer is a tough one, because you can still get back the null pointer that was in it. 00:14:56.879 --> 00:15:08.080 Anyhow, in the ring buffer thing that I illustrated, I now have a function, I now have an object where the only meaningful thing I can do is assign to it again, like you're talking about with an integer. 00:15:08.080 --> 00:15:08.559 Right. 00:15:08.559 --> 00:15:10.559 And so I said, you know what? 00:15:10.559 --> 00:15:26.240 I am, for the sake of the argument, so that we can talk about it, I'm gonna delete the move operations here and say, if moving always puts this thing in a state where it is not usable in any meaningful way, then it shouldn't be movable. 00:15:26.240 --> 00:15:29.039 And I just want people to think about that also, right? 00:15:29.039 --> 00:15:32.399 And I think that's I know, I think it's related to what your argument is. 00:15:32.720 --> 00:15:33.279 For sure. 00:15:33.279 --> 00:15:37.360 And this line of thinking leads us to uh, you know, destructive move, right? 00:15:37.360 --> 00:15:44.879 Which is if we had destructive move, I think your argument

might change and say, well, it is movable because move destroys the old thing, right? 00:15:44.879 --> 00:15:45.360 Right. 00:15:45.360 --> 00:15:45.840 Yeah. 00:15:45.840 --> 00:15:46.799 But we don't. 00:15:46.799 --> 00:15:56.879 And but many, you know, a certain a workable mental model, certainly a workable mental model is that after you move something, you should only assign or destroy assign to it or destroy it, right? 00:15:56.879 --> 00:15:57.279 Yes. 00:15:57.279 --> 00:16:00.080 That that is that is where many people start. 00:16:00.080 --> 00:16:03.440 That is how many people think of things, that is certainly a workable mental model. 00:16:03.440 --> 00:16:13.039 It happens that in the minutiae of C, that is not quite correct because it after it's moved from, it still is a member of the class. 00:16:13.039 --> 00:16:14.960 Its invariants still hold. 00:16:14.960 --> 00:16:18.480 Functions that don't have preconditions may still be called. 00:16:18.480 --> 00:16:25.039 And there are details of implementing some containers and or algorithms perhaps which rely on some of those things. 00:16:25.360 --> 00:16:31.360 And there's no way to know if the object has ever been moved from. 00:16:31.360 --> 00:16:38.720 If you ever pass anyone an immutable reference to this thing, it's possible they moved it. 00:16:38.720 --> 00:16:39.120 Right? 00:16:39.120 --> 00:16:39.440 Yeah. 00:16:39.440 --> 00:16:44.720 Like you you you pass an L you pat you think you're passing an L-value reference to a function. 00:16:44.720 --> 00:16:46.399 Haha, joke's on you. 00:16:46.399 --> 00:16:49.039 Internally inside the function, they still called stdMove. 00:16:49.039 --> 00:16:56.240 They cast it to an R value reference, they moved out the thing, and when your function is returned to you, you have an object that has now been moved from. 00:16:56.240 --> 00:16:57.679 There's no way to enforce it. 00:16:57.679 --> 00:16:58.240 Right. 00:16:58.240 --> 00:16:59.519 So, yes. 00:16:59.519 --> 00:17:03.039 Like the ideal, but we but but it's still C. 00:17:03.039 --> 00:17:05.839 The ideals are great, but we're programming it C. 00:17:05.839 --> 00:17:07.839 Yeah, I know. 00:17:10.319 --> 00:17:13.920 Well, as as I've been listening to this, you know, just hanging on for dear life. 00:17:13.920 --> 00:17:26.160 I've had this little voice in the back of my head while you know Jason and the second part of this conversation is talking about the multidimensional extension to that Howard Hinnan table, and I feel like uh my my brain is vibrating. 00:17:26.400 --> 00:17:38.799 By the way, I think that table certainly one of the early talks Howard gave with that table in it was a criminally underviewed talk, which I think I can dig up the links, and it was a talk at Bloomberg, it was an invited that Howard gave up. 00:17:39.039 --> 00:17:47.759 Alright, I will definitely I mean I have already, because I've been trying to at least, if not, find the links, get the you know, type the name down in the future. 00:17:47.759 --> 00:17:56.400 I have the article that meant and in the bottom of the image there is a hyperlink to the talk that that Howard Hinnant gave. 00:17:56.400 --> 00:17:57.759 I'm not sure if it's the exact same one. 00:17:57.759 --> 00:17:59.599 That's a problem with images, folks, though. 00:17:59.599 --> 00:18:07.279 You know, you can't click on the hyperlink in a in a JPEG or a PNG, or at least not yet, you know, maybe some future uh photo format. 00:18:07.680 --> 00:18:13.920 Uh send it to Claude and ask it to uh extract that URL for you, and then you could click on it. 00:18:14.240 --> 00:18:14.480 Maybe. 00:18:14.480 --> 00:18:19.920 I'm not sure that's the best you've uh you could just type it into the browser. 00:18:19.920 --> 00:18:22.400 Uh or you could just search for Howard Hinanth. 00:18:22.400 --> 00:18:29.680 I was also gonna say, we have we haven't actually reviewed uh, you know, maybe so yeah, talk a little bit about the other talk and we could talk about the comfort. 00:18:29.680 --> 00:18:35.599 Yeah, but like CPPCon, I I know Betton, you were only there for Friday, but uh Jason, uh I imagine you were there for the whole week. 00:18:35.599 --> 00:18:39.599 I mean you can tell us true or false, and and maybe you saw some talks while you were there. 00:18:39.599 --> 00:18:49.920 Like I always when I was a listener before I was a podcaster, I always liked getting like highlights of oh, I should definitely go watch this talk instead of having to sift through all hundreds of them to find the best one. 00:18:49.920 --> 00:18:52.480 So if you have any recommendations, if you don't, that's fine. 00:18:52.480 --> 00:18:53.599 But yeah, over to you. 00:18:53.599 --> 00:18:54.160 All 17. 00:18:54.720 --> 00:19:01.279 I'm gonna say unfortunately, I don't really have anything intelligent to tell you about CBPCon because I was absolutely wiped out. 00:19:01.279 --> 00:19:04.319 I flew from Europe, as many people do. 00:19:04.319 --> 00:19:14.160 But um, and then I taught the workshop on Saturday and Sunday, and then I actually had to fly to another client on Monday night, and I got back on Tuesday. 00:19:14.160 --> 00:19:14.799 Oh wow. 00:19:14.799 --> 00:19:25.920 So I missed like, yeah, I missed basically all of Monday and Tuesday, and then I had my own talks on Wednesday and Friday and a book signing on Thursday, and it was just like I I I wasn't really present. 00:19:26.480 --> 00:19:28.799 Well, in that case, I'm gonna plug a couple of talks. 00:19:28.799 --> 00:19:37.440 One, one by Dave Stefan, who is a regular at Denver Meetup, and it's called uh Refactoring in Three Acts or something of that. 00:19:37.440 --> 00:19:39.200 A Tale of Three Acts. 00:19:39.200 --> 00:19:40.400 I think that's a good talk. 00:19:40.400 --> 00:19:43.519 That is actually on YouTube, unlisted at the moment. 00:19:43.519 --> 00:19:48.880 But the actually it seems like the early access talks are free for everyone.

00:19:48.880 --> 00:19:49.920 I have no idea. 00:19:49.920 --> 00:19:50.960 I'm not sure. 00:19:50.960 --> 00:19:54.880 And the other talk I'm gonna plug is of course my colleague Michael Case's talk. 00:19:54.880 --> 00:19:56.960 That was on the Friday, so I did see it. 00:19:56.960 --> 00:20:01.359 And he was showing, and now I've forgotten the name of the talk, but Connor, no doubt you could dig it up. 00:20:01.359 --> 00:20:12.880 He was talking about the thesis, the abstract of his talk said, you know, doing basically doing doing firmware slash bare metal firmware with with contemporary C. 00:20:12.880 --> 00:20:23.680 Bringing bringing firmware into the the contemporary practices rather than staying in escaping 1996 was I think one of the phrases in the abstract. 00:20:23.920 --> 00:20:25.680 Alright, I will link to both of those and yeah. 00:20:25.680 --> 00:20:26.720 Be sure to check those out. 00:20:26.720 --> 00:20:29.519 Jason, do you want to h highlight any of your other talks you've given? 00:20:29.519 --> 00:20:42.000 And I should say I I promised my wife I would uh change a diaper in in it, so we have to uh time box the uh the question is how did you how did you time the child is what the real question I have here. 00:20:42.400 --> 00:20:45.920 Oh, I mean I imagine the diaper just needs to be changed and oh yeah. 00:20:45.920 --> 00:20:48.559 In the first month it's like a dozen times a day at least. 00:20:48.720 --> 00:20:49.200 Yeah. 00:20:49.200 --> 00:20:51.839 You know, without I you know what I'm gonna do? 00:20:51.839 --> 00:20:56.000 I'm gonna instead plug Dave's talk, which I have not seen yet. 00:20:56.000 --> 00:21:19.119 Because I have realized with side conversations with Dave plus seeing many of his talks, he he usually previews them at our meetup that he and I are coalescing, perhaps is the right term, convertible converging on on like how one actually goes about writing code that's maintainable, I think. 00:21:19.119 --> 00:21:26.880 And and so I am sure Tave's talk is good, and if Ben plugs it, then it's definitely good. 00:21:26.880 --> 00:21:42.079 And uh yeah, like you'll almost certainly I'm guessing that the average person who watches it will be slightly annoyed and say, I can't do that in my code, but then it's gonna bother you for the rest of your life because you're gonna wonder if you can pull it off in your code. 00:21:42.400 --> 00:21:42.640 Yeah. 00:21:42.640 --> 00:21:46.799 You're probably you're making me think certainly of the function length idea. 00:21:47.200 --> 00:21:47.519 Yes. 00:21:47.519 --> 00:21:48.480 Functional length. 00:21:48.480 --> 00:21:50.960 And so another talk, yeah, function length. 00:21:51.279 --> 00:21:54.400 The line length of functions, the number of lines in a function. 00:21:54.640 --> 00:21:54.880 Yeah. 00:21:54.880 --> 00:21:57.279 So they definitely asks in that talk. 00:21:57.440 --> 00:21:58.000 Sorry, Karen. 00:21:58.400 --> 00:21:59.519 And he oh no, he has. 00:21:59.519 --> 00:22:04.799 Very small numbers, what people most people would could think can to be impossibly small. 00:22:04.960 --> 00:22:08.160 And we should ask Connor. 00:22:08.160 --> 00:22:10.559 What do you think is the outside of APL? 00:22:10.559 --> 00:22:11.279 Let's say you're writing. 00:22:11.279 --> 00:22:13.759 Yeah, yeah. 00:22:13.759 --> 00:22:14.480 Yeah, right. 00:22:14.480 --> 00:22:17.759 What do you think is a how small is small? 00:22:17.759 --> 00:22:27.119 Is or what would you can the slight slightly more focused question is what length of function would you be wary about okaying in the code review? 00:22:27.119 --> 00:22:30.079 You know, if you saw a thousand line function in the code review, would that be too long? 00:22:30.079 --> 00:22:30.480 No, yeah. 00:22:30.480 --> 00:22:31.759 I mean that's way past the threshold. 00:22:31.759 --> 00:22:32.799 That would be okay. 00:22:32.799 --> 00:22:35.759 So if you saw a hundred line function, it depends. 00:22:36.000 --> 00:22:44.319 It depends, but like I uh in general, depending on the level that you're at, I really think my favorite functions are like, you know, five to ten. 00:22:44.319 --> 00:22:49.200 Like the grokkability and understandability of it is just like obvious. 00:22:49.200 --> 00:23:00.000 As soon as you as soon as I'm scrolling on GitHub in your PR, and I I do the the side by side, I don't do the unified, so it's like however many lines that is, then I then I'm asking. 00:23:00.000 --> 00:23:01.519 I'm not saying it's bad. 00:23:01.519 --> 00:23:05.039 I'm just saying I'm now asking myself, right to be this long? 00:23:05.039 --> 00:23:05.920 Sometimes it does. 00:23:05.920 --> 00:23:10.000 I'm not saying that all functions that can't fit on a single screen are too long. 00:23:10.319 --> 00:23:15.599 But we've entered we've definitely entered the realm of this is outside the ordinary and deserves attention to justify itself. 00:23:15.599 --> 00:23:15.839 Yeah. 00:23:16.079 --> 00:23:26.240 Because like some of the best code that I've seen, it's just it is like it's not even C it's like closure, and all of them are just these beautiful, little, concise, composed, you know, everything. 00:23:26.240 --> 00:23:41.759 It's it's you know what when you hear Stepanov or Sean Parent or or you, Ben, talk about like the composability of Albert, you can see that everything was so beautifully crafted to fit together that you only ever need to invoke, you know, five, six, seven things, and you just read it and it's like it's like reading poetry. 00:23:41.759 --> 00:23:42.559 It's it's so nice. 00:23:42.559 --> 00:23:45.279 And and you never are asking yourself, is this too long? 00:23:45.279 --> 00:23:46.720 Because it's obvious that it's not. 00:23:46.720 --> 00:23:50.079 It's obvious that you know it's just really well written code. 00:23:50.079 --> 00:23:54.000 C plus plus, I I don't find stum you stumble into that as often. 00:23:54.559 --> 00:23:54.880 No.

00:23:54.880 --> 00:24:00.640 The talk I gave at NDC Toronto the expression expression-based C. 00:24:00.640 --> 00:24:01.680 That's what it was. 00:24:01.680 --> 00:24:02.240 Thank you. 00:24:02.240 --> 00:24:03.359 That was directly. 00:24:04.400 --> 00:24:05.599 It is as of a couple months ago. 00:24:05.839 --> 00:24:06.960 It should be online now. 00:24:06.960 --> 00:24:08.480 That one is. 00:24:08.480 --> 00:24:13.759 I created that talk because of the mindworm from Dave from years ago. 00:24:13.759 --> 00:24:14.480 Alright. 00:24:14.480 --> 00:24:16.079 So that talk. 00:24:16.079 --> 00:24:22.319 Watch one of Dave's recent talks, then go watch that talk and and maybe you'll see where I was coming from. 00:24:22.640 --> 00:24:38.319 And Dave has practiced this in a decent sized codebase, you know, like in his in his production codebase, he is he has deliberately uh ratcheted up in CI the requirements for function length or function shortness, you know. 00:24:38.319 --> 00:24:48.799 And he's gone down from, you know, turning it on first and setting it something arbitrary like 100 and fixing those and then bringing it down over time to 50, below 50. 00:24:48.799 --> 00:24:49.920 I think he stopped. 00:24:49.920 --> 00:24:59.039 He, you know, like all of these things, he stopped before perhaps his complete ideal, but he stopped in a pragmatic sense at like 35 or something like that. 00:24:59.359 --> 00:25:05.519 And I've had students from Dave's teams many times, and that seems to be a process that's working. 00:25:05.519 --> 00:25:18.240 And I will say, last my last chat with him, we seem to agree that the only time where you can assume that this rule would be broken is if something where it's just naturally expressed in more lines of code. 00:25:18.240 --> 00:25:24.480 Like for some reason you're decoding a protocol and you naturally have a switch with like 50 case statements. 00:25:24.480 --> 00:25:28.319 Like, and and there's just there's no logical way to split this in half, right? 00:25:28.319 --> 00:25:29.039 Then yeah. 00:25:29.440 --> 00:25:39.839 And you don't, you know, if the compiler could optimize an array lookup into function pointer as well, then maybe you could bring it down, but sometimes performance the case that you can't. 00:25:40.319 --> 00:25:42.720 And but also readability of the code. 00:25:42.720 --> 00:25:47.200 Like sometimes it's it's just it just makes more sense, I think, often, but not always. 00:25:47.359 --> 00:25:47.599 Anyhow. 00:25:47.599 --> 00:26:13.839 I had this talk I was I had this talk that I wanted to give years ago and have never given it, and it was called format-driven development, which sounds kind of like something that a lot of people would disagree with, but it's really more of like a design talk in that like when I think about the that long case statements, like I'm really I'm praying that it's like case, colon, return, you know, single thing, and semicolon. 00:26:13.839 --> 00:26:30.960 And

like it, it like drives me not insane, but just like there's something about and and I've I've gone on a little in other talks, like I've given other speakers a hard time when they don't like use a monospace font and they don't use like formatting like that because there's oh it's just slideware. 00:26:30.960 --> 00:26:54.240 And I'm like, you're making it harder for people to like use the pattern recognition engine that is in all of our brains, and and so like when you see a case statement like that, and then only one of the case statements breaks into multiple lines and it's in the middle, it's just like, oh, like throw that thing in a function so that like even if all of it's raw code and then you have one function so that you can keep that kind of linear style and aligned style. 00:26:54.240 --> 00:27:00.000 Anyways, that's that kind of stuff I think leads to it goes hand in hand with keeping your functions short. 00:27:00.000 --> 00:27:14.319 Because when you when you try to reduce indentation, when you try to you know keep things linear and symmetric, you just naturally end up with shorter because the easier things to keep symmetric and readable and like and parallel with each other are short functions. 00:27:14.319 --> 00:27:18.960 When you have a big glob, you end up like with things that aren't at the same abstraction level. 00:27:18.960 --> 00:27:24.079 And and yeah, so anyways, I think if I had made the talk, people would have been like, this is stupid. 00:27:24.079 --> 00:27:27.839 You shouldn't you shouldn't be driving the writing of your code based on form. 00:27:27.839 --> 00:27:35.440 Like literally, I've done PRs where like some line was too long, and then I just refactored the whole function just to make it look more it didn't do anything different. 00:27:35.440 --> 00:27:42.400 It was just like reformatting, but at the end of it, it looks so much you would you would imagine I did something amazing there, but really it was just uh functionality. 00:27:42.400 --> 00:27:45.680 And I think that is my wife pinging on what's uh asking me to go. 00:27:45.759 --> 00:27:49.680 So you have more important things to do than talk to us. 00:27:49.680 --> 00:27:50.240 You do. 00:27:50.240 --> 00:27:52.880 Yes, well absolutely arguably, I guess, yeah. 00:27:53.039 --> 00:27:55.920 You do raising a baby is more important. 00:27:55.920 --> 00:27:56.559 Indeed. 00:27:56.559 --> 00:27:58.400 Yes, it is, it's more important. 00:27:58.400 --> 00:28:04.480 Uh but thank you so much, Jason, for taking the time uh across the pond at a different time zone and uh to Ben as well. 00:28:04.480 --> 00:28:05.680 I guess you're in a different time zone as well. 00:28:05.680 --> 00:28:06.720 Yeah, thanks, Jason. 00:28:06.720 --> 00:28:07.519 Yeah, absolutely. 00:28:07.519 --> 00:28:13.039 Hopefully, we'll bump all the three of us uh in a conference in the next three hundred and sixty five days. 00:28:13.039 --> 00:28:13.519 Yeah. 00:28:13.519 --> 00:28:14.400 At some point. 00:28:14.400 --> 00:28:24.559 Be sure to check these show notes either in your podcast app or at adspthepodcast.com for links to anything we mentioned in today's episode, as well as a link to a GitHub discussion where you can leave thoughts, comments, and questions. 00:28:24.559 --> 00:28:25.359 Thanks for listening. 00:28:25.359 --> 00:28:26.960 We hope you enjoyed and have a great day. 00:28:26.960 --> 00:28:29.119 I am the anti price. 00:28:29.519 --> 00:28:29.839 Um