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+WEBVTT captioned by sachac, checked by sachac
+
+NOTE Introduction
+
+00:00:00.000 --> 00:00:08.359
+Hello, everyone, and welcome to Speedcubing in Emacs.
+
+00:00:08.360 --> 00:00:10.119
+First of all, a little bit about myself.
+
+00:00:10.120 --> 00:00:13.679
+My name is Vasilij Schneidermann. Online, I go by wasamasa.
+
+00:00:13.680 --> 00:00:18.039
+I'm 31 years old. I work in information security,
+
+00:00:18.040 --> 00:00:20.479
+and I do consulting and hacking
+
+00:00:20.480 --> 00:00:22.479
+and stuff like figuring out
+
+00:00:22.480 --> 00:00:25.279
+how to break into other people's computers
+
+00:00:25.280 --> 00:00:29.359
+and how to secure their systems basically.
+
+00:00:29.360 --> 00:00:31.439
+You can reach me by email.
+
+00:00:31.440 --> 00:00:36.639
+I do have a self-hosted code repository thingy going on.
+
+00:00:36.640 --> 00:00:40.399
+I have a blog, and you can find me
+
+00:00:40.400 --> 00:00:45.919
+in some other places online, like IRC for example.
+
+00:00:45.920 --> 00:00:48.679
+So about the talk itself,
+
+00:00:48.680 --> 00:00:52.839
+I used to be into the Rubik's cube when I was in school.
+
+00:00:52.840 --> 00:00:54.039
+I forgot about it, though,
+
+00:00:54.040 --> 00:00:56.279
+because these cubes were not very good.
+
+00:00:56.280 --> 00:01:02.279
+Recently I did find some cheap looking cube at a shop.
+
+00:01:02.280 --> 00:01:04.119
+Did not pay terribly much for it.
+
+00:01:04.120 --> 00:01:07.039
+It was so, so much better than my old cube,
+
+00:01:07.040 --> 00:01:08.639
+it was unreal.
+
+00:01:08.640 --> 00:01:11.479
+This motivated me to get back into
+
+00:01:11.480 --> 00:01:13.559
+this really weird kind of hobby.
+
+00:01:13.560 --> 00:01:17.999
+For this, you need to be good at producing
+
+00:01:18.000 --> 00:01:19.399
+a truly random scramble
+
+00:01:19.400 --> 00:01:22.319
+and timing your attempts to get any better at it.
+
+00:01:22.320 --> 00:01:23.719
+There is, of course, existing software
+
+00:01:23.720 --> 00:01:26.239
+to do the scrambling for you and the recording
+
+00:01:26.240 --> 00:01:28.079
+and the timekeeping and such,
+
+00:01:28.080 --> 00:01:31.239
+but all the good options seem to be either web or mobile,
+
+00:01:31.240 --> 00:01:33.239
+for example the cstimer software
+
+00:01:33.240 --> 00:01:35.399
+or the twisty-timer app on Android.
+
+
+NOTE Cubing in Emacs
+
+00:01:35.400 --> 00:01:39.319
+To my surprise, I did not find a single decent option
+
+00:01:39.320 --> 00:01:41.959
+inside Emacs, so this is basically a case study
+
+00:01:41.960 --> 00:01:44.999
+how to do better. For this, I wanted to make use of
+
+00:01:45.000 --> 00:01:47.799
+all the cool new Emacs features that appeared,
+
+00:01:47.800 --> 00:01:50.879
+like the SVG library; Transient,
+
+00:01:50.880 --> 00:01:53.599
+the library used for the Magit-style interfaces;
+
+00:01:53.600 --> 00:01:56.439
+and the recently added sqlite-mode.
+
+00:01:56.440 --> 00:02:01.159
+And most importantly it was about having fun.
+
+NOTE Prior art
+
+00:02:01.160 --> 00:02:02.759
+So here's a full list of prior art,
+
+00:02:02.760 --> 00:02:04.279
+I will not go into detail about this,
+
+00:02:04.280 --> 00:02:06.239
+but basically we have things solving
+
+00:02:06.240 --> 00:02:08.039
+very different parts of this,
+
+00:02:08.040 --> 00:02:10.759
+but not all of it. For example: we have several,
+
+00:02:10.760 --> 00:02:14.239
+we have a timer. We have several solvers.
+
+00:02:14.240 --> 00:02:16.039
+We have some scramblers.
+
+00:02:16.040 --> 00:02:19.359
+We have some whole-cube simulators, including a 3D one.
+
+00:02:19.360 --> 00:02:20.759
+We have something for making it easier
+
+00:02:20.760 --> 00:02:23.119
+to enter your algorithms in the notation.
+
+00:02:23.120 --> 00:02:25.919
+But nothing that does all of those things in one package,
+
+00:02:25.920 --> 00:02:28.119
+which kind of surprised me.
+
+00:02:28.120 --> 00:02:32.039
+So I present the `wca-prep` package.
+
+NOTE The name
+
+00:02:32.040 --> 00:02:35.559
+So the name, I found it difficult
+
+00:02:35.560 --> 00:02:39.959
+to come up with a good name and so I looked
+
+00:02:39.960 --> 00:02:42.559
+and I saw, well there's this World Cube Association
+
+00:02:42.560 --> 00:02:46.039
+that holds these competitions where you compete.
+
+00:02:46.040 --> 00:02:47.759
+They do this for the Rubik's cube
+
+00:02:47.760 --> 00:02:48.919
+but also a few others,
+
+00:02:48.920 --> 00:02:50.799
+so there's like a standardized list
+
+00:02:50.800 --> 00:02:52.639
+of events they have for this.
+
+00:02:52.640 --> 00:02:55.159
+There is a standard notation for this
+
+00:02:55.160 --> 00:02:56.519
+and rules and everything.
+
+00:02:56.520 --> 00:02:58.199
+And the goal of my package is basically
+
+00:02:58.200 --> 00:03:01.279
+to help prepare myself for such a competition
+
+00:03:01.280 --> 00:03:03.679
+and in fact a week ago I went to my first one
+
+00:03:03.680 --> 00:03:06.719
+which was wild, but pretty cool.
+
+00:03:06.720 --> 00:03:10.919
+So for this reason I chose this name wca-prep,
+
+00:03:10.920 --> 00:03:13.639
+because it helps me prepare for this kind of competition
+
+00:03:13.640 --> 00:03:16.519
+and this limited the scope significantly,
+
+NOTE What's in wca-prep
+
+00:03:16.520 --> 00:03:18.999
+I have a scrambler, visualization of the scramble,
+
+00:03:19.000 --> 00:03:23.319
+timer, and statistics.
+
+00:03:23.320 --> 00:03:25.559
+I excluded pretty much everything else I've seen.
+
+00:03:25.560 --> 00:03:28.788
+For this reason, I only tried to focus on
+
+00:03:28.789 --> 00:03:32.199
+some very basic puzzles I can solve comfortably,
+
+00:03:32.200 --> 00:03:34.839
+and did not want to do anything else
+
+00:03:34.840 --> 00:03:36.439
+that may complicate things significantly.
+
+00:03:36.440 --> 00:03:40.479
+No other kinds of puzzles, no simulation, no solving,
+
+00:03:40.480 --> 00:03:43.919
+no exotic events, and no specialized scrambles
+
+00:03:43.920 --> 00:03:49.239
+that are only good for practicing specific algorithms.
+
+NOTE Demo
+
+00:03:49.240 --> 00:03:54.199
+So at this point the organizer should hopefully show
+
+00:03:54.200 --> 00:03:57.999
+a small video I've prepared, a one minute video showing how
+
+00:03:58.000 --> 00:05:15.239
+I actually use this to solve a cube and to time my solve.
+
+NOTE Challenges: Representing the cube
+
+00:05:15.240 --> 00:05:18.508
+Okay, so building this thing, there were several challenges.
+
+00:05:18.509 --> 00:05:20.508
+The first one was how do I even represent
+
+00:05:20.509 --> 00:05:22.468
+the state of a Rubik's cube.
+
+00:05:22.469 --> 00:05:25.508
+For this there are many possible representations,
+
+00:05:25.509 --> 00:05:27.708
+no obvious best solution.
+
+00:05:27.709 --> 00:05:29.628
+I did not, well, what helped me was that
+
+00:05:29.629 --> 00:05:31.988
+I did not have to programmatically solve this thing,
+
+00:05:31.989 --> 00:05:35.188
+so I picked the easiest possible representation
+
+00:05:35.189 --> 00:05:38.268
+which is just an array of every single facelet.
+
+00:05:38.269 --> 00:05:42.508
+For a 3x3 cube you have 9 facelets on one side,
+
+00:05:42.509 --> 00:05:47.268
+so times 6 sides you would have 54 elements in this array.
+
+00:05:47.269 --> 00:05:49.708
+So with this representation, it's very simple,
+
+00:05:49.709 --> 00:05:52.388
+but it's kind of weird to do scrambles with this.
+
+00:05:52.389 --> 00:05:54.908
+But otherwise, it worked very, very well.
+
+00:05:54.909 --> 00:05:57.268
+In the future, I plan to learn some group theory,
+
+00:05:57.269 --> 00:05:58.748
+pick a better representation
+
+00:05:58.749 --> 00:06:01.188
+and do this in a much, much more elegant way
+
+00:06:01.189 --> 00:06:07.868
+without compromising speed too much.
+
+00:06:07.869 --> 00:06:10.708
+Yes. Once I had the representation,
+
+00:06:10.709 --> 00:06:13.628
+the scrambling itself should not be too hard.
+
+00:06:13.629 --> 00:06:17.748
+For this, it's important to consider that basically
+
+00:06:17.749 --> 00:06:19.148
+if you do a face turn
+
+00:06:19.149 --> 00:06:22.428
+you end up swapping some facelets with other facelets,
+
+00:06:22.429 --> 00:06:26.028
+that's the easiest way to think about this.
+
+00:06:26.029 --> 00:06:29.268
+To determine which one goes into which one's position,
+
+00:06:29.269 --> 00:06:32.470
+it was pretty confusing to figure this out.
+
+00:06:32.471 --> 00:06:34.308
+For this I went through a few papers,
+
+00:06:34.309 --> 00:06:36.028
+and I found one which suggested
+
+00:06:36.029 --> 00:06:37.948
+to just build a cube out of paper,
+
+00:06:37.949 --> 00:06:40.028
+number every facelet, and turn it
+
+00:06:40.029 --> 00:06:44.348
+and keep track of which facelet moved into which position.
+
+00:06:44.349 --> 00:06:47.508
+And programmatically, the `cl-rotatef` macro
+
+00:06:47.509 --> 00:06:49.388
+was very, very useful for doing this kind of
+
+00:06:49.389 --> 00:06:51.628
+in-place swapping you need for this operation.
+
+00:06:51.629 --> 00:06:54.868
+So in the future, group theory would hopefully
+
+00:06:54.869 --> 00:06:57.988
+make this a bit less awkward.
+
+00:06:57.989 --> 00:07:00.108
+Here's a photo of this paper cube I made
+
+00:07:00.109 --> 00:07:03.868
+along with a real cube. As you can see
+
+00:07:03.869 --> 00:07:07.348
+mathematically speaking, they are the same thing,
+
+00:07:07.349 --> 00:07:09.268
+they just look very, very different.
+
+NOTE Scrambling
+
+00:07:09.269 --> 00:07:14.308
+So the scramble algorithm itself,
+
+00:07:14.309 --> 00:07:19.428
+I pondered how this would even be done. In the competitions,
+
+00:07:19.429 --> 00:07:21.588
+They do this in a very, very elaborate way.
+
+00:07:21.589 --> 00:07:22.748
+They generate a random cube,
+
+00:07:22.749 --> 00:07:25.388
+they try to solve it, and if it's solvable
+
+00:07:25.389 --> 00:07:28.548
+they use these solution moves
+
+00:07:28.549 --> 00:07:30.828
+to turn into a scramble basically.
+
+00:07:30.829 --> 00:07:34.948
+And they also make sure to canonicalize the moves,
+
+00:07:34.949 --> 00:07:38.548
+so if you have subsequent moves that can be simplified,
+
+00:07:38.549 --> 00:07:40.588
+they do simplify these as much as possible.
+
+00:07:40.589 --> 00:07:41.228
+For example,
+
+00:07:41.229 --> 00:07:43.748
+if you have two subsequent rotations in one direction,
+
+00:07:43.749 --> 00:07:46.668
+it's turned into a different kind of rotation,
+
+00:07:46.669 --> 00:07:49.388
+so 90 and 90 equals 180.
+
+00:07:49.389 --> 00:07:53.308
+And the other Elisp scramblers I looked at,
+
+00:07:53.309 --> 00:07:55.108
+they generate random moves.
+
+00:07:55.109 --> 00:07:57.508
+Some of them do canonicalize. Not all of them.
+
+00:07:57.509 --> 00:08:00.908
+This one tries to do the best low-fi thing,
+
+00:08:00.909 --> 00:08:02.388
+that is, generating random moves,
+
+00:08:02.389 --> 00:08:04.028
+canonicalizing and repeating
+
+00:08:04.029 --> 00:08:09.548
+until enough have been generated.
+
+NOTE Visualization
+
+00:08:09.549 --> 00:08:13.148
+For the visualization I had to figure out
+
+00:08:13.149 --> 00:08:14.508
+something else too complicated.
+
+00:08:14.509 --> 00:08:17.228
+For this, I tried to figure out
+
+00:08:17.229 --> 00:08:19.868
+where every facelift would end up in the puzzle view
+
+00:08:19.869 --> 00:08:21.428
+when you would unfold it.
+
+00:08:21.429 --> 00:08:25.668
+And for this, I did not consider the facelet orientation.
+
+00:08:25.669 --> 00:08:29.268
+This may be important later for some other puzzles
+
+00:08:29.269 --> 00:08:31.148
+where you can end up with very twisted faces,
+
+00:08:31.149 --> 00:08:33.028
+but for simple cubes, it's not a problem.
+
+00:08:33.029 --> 00:08:36.308
+My initial prototype used colored text,
+
+00:08:36.309 --> 00:08:38.748
+but later, I used the SVG library.
+
+00:08:38.749 --> 00:08:41.588
+It turned out to be easy enough to use, actually.
+
+00:08:41.589 --> 00:08:46.108
+Currently, I have hard-coded face-color mappings,
+
+00:08:46.109 --> 00:08:49.108
+but I plan to replace this so that theming is possible.
+
+00:08:49.109 --> 00:08:51.588
+For example, if you happen to have a cube
+
+00:08:51.589 --> 00:08:54.689
+that does not have the same color mappings as I do,
+
+00:08:54.690 --> 00:08:56.468
+then you should be able to fix this.
+
+NOTE UI with Transient
+
+00:08:56.469 --> 00:09:01.428
+Next challenge was to build
+
+00:09:01.429 --> 00:09:03.948
+a beautiful intuitive UI with Transient.
+
+00:09:03.949 --> 00:09:06.868
+The reason why I chose this is
+
+00:09:06.869 --> 00:09:10.348
+because it would be self-documenting and Magit-style,
+
+00:09:10.349 --> 00:09:12.348
+and everyone knows how Magit works basically.
+
+00:09:12.349 --> 00:09:15.308
+Since Transient has become part of Emacs,
+
+00:09:15.309 --> 00:09:17.228
+there is really no reason to not try it out.
+
+00:09:17.229 --> 00:09:21.668
+The problem was documentation is difficult to understand.
+
+00:09:21.669 --> 00:09:23.388
+It's very abstract and high level,
+
+00:09:23.389 --> 00:09:25.868
+and it's hard to figure out. "Okay,
+
+00:09:25.869 --> 00:09:26.788
+I want to do something,
+
+00:09:26.789 --> 00:09:28.908
+how am I supposed to do this?"
+
+00:09:28.909 --> 00:09:33.348
+I did find transient-showcase, which has lots of examples,
+
+00:09:33.349 --> 00:09:35.628
+but they don't really feel finished
+
+00:09:35.629 --> 00:09:39.068
+and not realistic enough.
+
+00:09:39.069 --> 00:09:40.748
+When I tried to use the package,
+
+00:09:40.749 --> 00:09:42.908
+I got plenty of unhelpful error messages
+
+00:09:42.909 --> 00:09:44.108
+when using it incorrectly.
+
+00:09:44.109 --> 00:09:45.948
+I did manage to figure it out,
+
+00:09:45.949 --> 00:09:50.588
+but I plan to find more actual examples of it,
+
+00:09:50.589 --> 00:09:53.428
+to have an executable reference basically
+
+00:09:53.429 --> 00:09:55.628
+and try to improve my use of it.
+
+NOTE Book-keeping with SQLite
+
+00:09:55.629 --> 00:10:01.548
+For the book-keeping, I used SQLite.
+
+00:10:01.549 --> 00:10:04.548
+This is a very recent addition to Emacs,
+
+00:10:04.549 --> 00:10:07.308
+it only appeared in the current major version.
+
+00:10:07.309 --> 00:10:09.388
+It's still very early days.
+
+00:10:09.389 --> 00:10:13.028
+I found some oddities, one of them turned out to be
+
+00:10:13.029 --> 00:10:14.828
+a bug in the transaction macro.
+
+00:10:14.829 --> 00:10:17.588
+Like basically, if you do an SQL transaction
+
+00:10:17.589 --> 00:10:20.188
+and an error happens, then every helper I found
+
+00:10:20.189 --> 00:10:20.948
+does a rollback on an error.
+
+00:10:20.949 --> 00:10:26.748
+But this one did not. It actually committed on an error,
+
+00:10:26.749 --> 00:10:29.868
+and this was very weird to figure out.
+
+00:10:29.869 --> 00:10:34.308
+I reported a bug. Eli was nice enough to send me a patch.
+
+00:10:34.309 --> 00:10:35.428
+We did some patch review,
+
+00:10:35.429 --> 00:10:37.988
+and he ended up fixing it properly.
+
+00:10:37.989 --> 00:10:45.668
+So yes, there's still a lot to be done there, and yeah,
+
+00:10:45.669 --> 00:10:46.908
+the API is very basic.
+
+00:10:46.909 --> 00:10:48.908
+You don't have convenience helpers
+
+00:10:48.909 --> 00:10:51.308
+like fetch the first row or fetch the first value
+
+00:10:51.309 --> 00:10:54.429
+or anything, but they're easy enough to write yourself.
+
+00:10:54.430 --> 00:10:56.369
+And the biggest challenge with this bookkeeping part
+
+00:10:56.370 --> 00:10:58.028
+was figuring out a decent schema,
+
+00:10:58.029 --> 00:11:00.148
+like how to organize data correctly
+
+00:11:00.149 --> 00:11:02.348
+so that it would not be awkward to manipulate.
+
+00:11:02.349 --> 00:11:05.748
+And with this, you can finally build a package
+
+00:11:05.749 --> 00:11:07.388
+that remembers its state properly
+
+00:11:07.389 --> 00:11:10.468
+and don't have to run into foot guns
+
+00:11:10.469 --> 00:11:12.628
+with Lisp-style serialization, deserialization.
+
+NOTE Conclusion
+
+00:11:12.629 --> 00:11:18.188
+So yes, that concludes it so far.
+
+00:11:18.189 --> 00:11:22.188
+So what did I learn from this exercise?
+
+00:11:22.189 --> 00:11:24.508
+Well, there are still plenty of packages
+
+00:11:24.509 --> 00:11:25.588
+for Emacs to be written.
+
+00:11:25.589 --> 00:11:28.908
+If you think everything you can think of
+
+00:11:28.909 --> 00:11:31.348
+or you need has already been written, well, guess what?
+
+00:11:31.349 --> 00:11:31.788
+No.
+
+00:11:31.789 --> 00:11:34.044
+These are still plenty of specialized things
+
+00:11:34.045 --> 00:11:36.788
+that could need your help.
+
+00:11:36.789 --> 00:11:39.788
+These cubes do not require advanced mathematics,
+
+00:11:39.789 --> 00:11:41.148
+contrary to what you may think.
+
+00:11:41.149 --> 00:11:44.708
+Yes, you can apply advanced mathematics to them
+
+00:11:44.709 --> 00:11:47.468
+if you want to, but you don't have to.
+
+00:11:47.469 --> 00:11:50.988
+What surprised me about this is basically group theory.
+
+00:11:50.989 --> 00:11:52.068
+I've heard of it before.
+
+00:11:52.069 --> 00:11:53.828
+It seemed to be a meme, basically,
+
+00:11:53.829 --> 00:11:56.468
+because it has been like mostly Haskell people
+
+00:11:56.469 --> 00:11:58.188
+being very excited about this
+
+00:11:58.189 --> 00:12:02.508
+and it seemed kind of, like, divorced from reality, basically.
+
+00:12:02.509 --> 00:12:05.948
+But this puzzle, it actually proves that yes,
+
+00:12:05.949 --> 00:12:06.948
+it has its use.
+
+00:12:06.949 --> 00:12:08.428
+It definitely has.
+
+00:12:08.429 --> 00:12:11.388
+You just have to find the right problem matching it,
+
+00:12:11.389 --> 00:12:13.468
+and yeah.
+
+00:12:13.469 --> 00:12:15.388
+So yeah, once I understand it better,
+
+00:12:15.389 --> 00:12:18.548
+the topic, I expect to write better code.
+
+00:12:18.549 --> 00:12:24.468
+These new Emacs features, they work well enough.
+
+00:12:24.469 --> 00:12:25.908
+There are some rough edges.
+
+00:12:25.909 --> 00:12:27.428
+They definitely need more testing.
+
+00:12:27.429 --> 00:12:30.668
+So please, please, everyone,
+
+00:12:30.669 --> 00:12:34.548
+if you write Elisp, please try SQLite or Transient
+
+00:12:34.549 --> 00:12:36.708
+or anything else that looks cool and shiny.
+
+00:12:36.709 --> 00:12:38.468
+Report bugs.
+
+00:12:38.469 --> 00:12:41.588
+Find ways to improve them, anything. And yeah,
+
+00:12:41.589 --> 00:12:44.868
+I'm sure that if we do this,
+
+00:12:44.869 --> 00:12:47.668
+then Emacs will continue to get even better.
+
+00:12:47.669 --> 00:12:51.788
+So yeah, what's next for this package?
+
+00:12:51.789 --> 00:12:55.988
+Well, I could... There are lots of obvious UI improvements
+
+00:12:55.989 --> 00:12:57.348
+and testing to be done.
+
+00:12:57.349 --> 00:12:59.708
+I basically want to reach feature parity
+
+00:12:59.709 --> 00:13:02.428
+with the twisty-timer app, which this is very much inspired by.
+
+00:13:02.429 --> 00:13:06.668
+I want nice-looking stats like graphical ones
+
+00:13:06.669 --> 00:13:08.788
+instead of just a simple list of times.
+
+00:13:08.789 --> 00:13:11.228
+And I want support for more puzzles, of course,
+
+00:13:11.229 --> 00:13:12.548
+not just the simple cubes,
+
+00:13:12.549 --> 00:13:14.588
+but as I progress learning these puzzles,
+
+00:13:14.589 --> 00:13:18.068
+I want to have Emacs supporting me for this.
+
+00:13:18.069 --> 00:13:22.428
+But generally, it's a very open-ended package.
+
+00:13:22.429 --> 00:13:26.628
+And this concludes the talk.
+
+00:13:26.629 --> 00:13:30.909
+Thank you very much.