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diff --git a/2021/captions/emacsconf-2021-janitor--a-day-in-the-life-of-a-janitor--stefan-monnier--main.vtt b/2021/captions/emacsconf-2021-janitor--a-day-in-the-life-of-a-janitor--stefan-monnier--main.vtt new file mode 100644 index 00000000..7e9e4bb8 --- /dev/null +++ b/2021/captions/emacsconf-2021-janitor--a-day-in-the-life-of-a-janitor--stefan-monnier--main.vtt @@ -0,0 +1,1780 @@ +WEBVTT + +00:01.520 --> 00:04.400 +Hello, my name is Stefan Monnier, + +00:04.400 --> 00:06.799 +and I'm going to talk to you about-- + +00:06.799 --> 00:08.240 +well, I'm going to present a bit + +00:08.240 --> 00:11.840 +of the life of a janitor. + +00:11.840 --> 00:14.050 +So by and large, there's just + +00:14.050 --> 00:16.299 +nothing to see here, + +00:16.299 --> 00:17.199 +and that's probably + +00:17.199 --> 00:18.240 +not super interesting, + +00:18.240 --> 00:19.920 +but some of you might actually like to + +00:19.920 --> 00:00:23.050 +see how I work, so I figured why not. + +00:25.359 --> 00:27.279 +Usually what I do just doesn't make any + +00:27.279 --> 00:00:29.920 +any significant difference, + +00:00:29.920 --> 00:00:32.160 +and so I basically take existing code + +00:00:32.160 --> 00:00:35.040 +that's working, and I try to change it + +00:00:35.040 --> 00:00:37.680 +hopefully without breaking it too much + +00:00:37.680 --> 00:00:40.079 +and make it slightly more... + +00:40.079 --> 00:42.719 +you know, following some of the more + +00:42.719 --> 00:44.640 +modern style, let's say, + +00:44.640 --> 00:00:46.719 +and sometimes along the way, + +00:00:46.719 --> 00:00:50.399 +it actually fixes some bugs. + +00:50.399 --> 00:00:51.983 +More concretely, the kind of things + +00:00:51.983 --> 00:00:54.079 +that I do is basically activate + +00:00:54.079 --> 00:00:54.480 +lexical scoping-- + +00:54.480 --> 00:56.239 +that's really my main goal usually-- + +00:56.239 --> 00:58.960 +but also do things like convert + +00:58.960 --> 00:01:00.719 +from `cl` to `cl-lib`, + +00:01:00.719 --> 00:01:01.440 +sometimes I have to + +01:01.440 --> 01:03.760 +fix some compilation dependencies, + +01:03.760 --> 01:07.280 +I might convert from `defadvice` to `advice-add`, + +01:07.280 --> 01:11.439 +and many of the things-- + +01:11.439 --> 00:01:13.119 +in terms of number of changes, + +00:01:13.119 --> 00:01:14.000 +most of them are actually + +00:01:14.000 --> 00:01:16.560 +changing `quote fun` to `hash quote fun` + +00:01:16.560 --> 00:01:17.360 +because I prefer it, + +01:17.360 --> 00:01:19.920 +but also it often helps me + +00:01:19.920 --> 00:01:21.439 +have a better understanding + +00:01:21.439 --> 00:01:23.920 +of which function is called where, + +01:23.920 --> 01:26.799 +and so the warnings I get from it + +01:26.799 --> 01:28.799 +sometimes help me. You look concretely... + +01:28.799 --> 00:01:30.880 +it's not nothing really clear; + +00:01:30.880 --> 00:01:33.360 +it's more in terms of helping me + +00:01:33.360 --> 00:01:35.759 +have a mental image + +00:01:35.759 --> 00:01:39.439 +of how the package works. + +01:39.439 --> 01:42.880 +So let's take a look. + +01:42.880 --> 00:01:45.840 +I'm going to start with + +00:01:45.840 --> 00:01:46.799 +the package `heap`, + +00:01:46.799 --> 00:01:50.560 +which I saw had a few weird things in it, + +00:01:50.560 --> 00:01:53.680 +so I'm going to compile it. + +01:53.680 --> 01:55.600 +That's basically the way the way I work, + +01:55.600 --> 00:01:57.840 +right. I take a package. + +00:01:57.840 --> 00:02:00.479 +I just pass it to the byte compiler. + +00:02:00.479 --> 00:02:02.159 +I do that by just having + +02:02.159 --> 02:04.560 +a clone of the whole + +02:04.560 --> 00:02:06.799 +GNU ELPA repository, + +00:02:06.799 --> 00:02:10.000 +and so that's why I built them. + +02:10.000 --> 02:11.520 +I use the build rules + +02:11.520 --> 02:15.120 +from the GNU ELPA repository. + +02:15.120 --> 00:02:16.720 +These build rules enforce-- + +00:02:16.720 --> 00:02:17.680 +make sure that the files + +00:02:17.680 --> 00:02:19.680 +are compiled in a clean environment + +00:02:19.680 --> 00:02:21.920 +so you get fairly good warnings. + +00:02:21.920 --> 00:02:23.680 +If you look at the warnings you see here, + +00:02:23.680 --> 00:02:24.720 +there's a lot of things + +00:02:24.720 --> 00:02:26.480 +which are completely irrelevant, + +00:02:26.480 --> 00:02:28.400 +which are due to details + +00:02:28.400 --> 00:02:30.319 +of the way I have my Emacs set up + +00:02:30.319 --> 00:02:31.599 +and some of the local changes + +00:02:31.599 --> 00:02:34.319 +I had in it so, you know, + +00:02:34.319 --> 00:02:35.280 +there's no point + +00:02:35.280 --> 00:02:37.920 +paying too much attention to it, + +02:37.920 --> 02:40.400 +but here we have a first warning. + +02:40.400 --> 02:42.959 +We see that this is using `cl`, + +02:42.959 --> 02:45.040 +so we want to change this to `cl-lib`, + +02:45.040 --> 00:02:46.879 +but that also means + +00:02:46.879 --> 00:02:48.400 +that we may have a new dependency + +00:02:48.400 --> 00:02:49.920 +on the `cl-lib` package, + +00:02:49.920 --> 00:02:51.120 +so we have to go check + +00:02:51.120 --> 00:02:52.000 +the start of the file + +00:02:52.000 --> 00:02:54.080 +to see if it already declares + +00:02:54.080 --> 00:02:56.800 +some dependency, and we see it doesn't, + +02:56.800 --> 00:03:00.640 +not even on a on a recent-enough Emacs, + +00:03:00.640 --> 00:03:02.325 +so we have to add-- + +00:03:02.325 --> 00:03:05.360 +sorry, that's not going very well... + +03:05.360 --> 03:06.480 +oh... + +03:06.480 --> 03:08.560 +okay, we're going to get there somewhere... + +03:08.560 --> 03:13.200 +somehow... + +03:13.200 --> 03:18.020 +oh, that still wasn't it, wow, okay-- + +03:20.480 --> 03:22.159 +and along the way... + +03:22.159 --> 00:03:24.159 +Of course, since we converted to `cl-lib`, + +00:03:24.159 --> 00:03:26.159 +we have to update the uses + +00:03:26.159 --> 00:03:29.840 +so `defstruct` shouldn't be used anymore. + +03:29.840 --> 03:31.599 +We may want to reindent this + +03:31.599 --> 03:36.000 +to get something a bit cleaner. + +03:37.040 --> 00:03:40.589 +We have here a missing quote... + +00:03:40.589 --> 00:03:41.920 +hash, sorry. + +03:41.920 --> 00:03:46.480 +We have `decf`, so `decf` is here, + +03:46.480 --> 00:03:48.000 +and that needs to be replaced + +00:03:48.000 --> 00:03:49.920 +with `cl-decf`. + +00:03:49.920 --> 00:03:51.120 +Sometimes it's worth doing + +00:03:51.120 --> 00:03:53.360 +a search-and-replace. + +00:03:53.360 --> 00:03:54.799 +Here I see there's only two, + +00:03:54.799 --> 00:03:57.760 +so it's not worth the trouble; + +03:57.760 --> 00:04:00.711 +I just do it by hand, and that's it. + +00:04:00.711 --> 00:04:02.000 +Well, that was easy. + +04:02.000 --> 04:05.000 +So let's recompile, see what it says. + +04:10.159 --> 04:12.959 +Ah, this is clean. Perfect! + +04:12.959 --> 04:15.000 +Let's.. we can go see... + +04:15.000 --> 04:17.280 +There is another one I had. + +04:17.280 --> 04:20.239 +Was it `counsel`, I think. Yes. + +04:20.239 --> 00:04:24.160 +So also I saw some funny things + +00:04:24.160 --> 00:04:24.320 +going on here. + +04:24.320 --> 00:04:26.479 +So I'm going to do + +00:04:26.479 --> 00:04:31.040 +the same procedure as before: + +00:04:31.040 --> 00:04:32.800 +I just compile the file + +00:04:32.800 --> 00:04:35.000 +and look at the warnings. + +04:38.000 --> 04:40.479 +Oh, we have many more here. + +04:40.479 --> 04:43.120 +So let's see... + +04:43.120 --> 00:04:46.504 +Okay, so we have missing quotes-- + +00:04:46.504 --> 00:04:49.240 +oh, hashes. They're not really missing; + +04:49.240 --> 04:54.639 +it's just a personal preference. + +04:54.639 --> 04:57.440 +Oh, here... here's an important one: + +04:57.440 --> 04:59.280 +so as you know, + +04:59.280 --> 05:00.639 +if you look at the top of the file, + +05:00.639 --> 00:05:02.240 +you see that here + +00:05:02.240 --> 00:05:04.960 +it says it's using lexical binding, + +05:04.960 --> 05:07.120 +yet it's not fully using lexical binding, + +05:07.120 --> 00:05:08.960 +because as we just saw, + +00:05:08.960 --> 00:05:11.039 +there's a call to the `eval` function + +00:05:11.039 --> 00:05:11.680 +with only one argument, + +05:11.680 --> 05:13.280 +which means the second argument is nil, + +05:13.280 --> 05:16.880 +which means that the expression read + +05:16.880 --> 00:05:19.520 +by `read` here is going to be evaluated + +05:19.520 --> 00:05:22.160 +using the old dialects, + +00:05:22.160 --> 00:05:24.240 +which is only dynamic scoping. + +00:05:24.240 --> 00:05:25.680 +So here I like to just change this + +00:05:25.680 --> 00:05:26.800 +to use lexical scoping, + +05:26.800 --> 00:05:28.080 +which in most cases + +00:05:28.080 --> 00:05:29.680 +just doesn't make any difference. + +00:05:29.680 --> 00:05:30.870 +It just makes me feel better. + +05:35.919 --> 05:40.160 +So there's lots of those hashes + +05:40.160 --> 05:41.759 +all over the place. + +05:43.680 --> 05:45.680 +It's not strictly necessary, as you know, + +05:45.680 --> 05:51.500 +but I'm just going to add them anyway. + +05:52.479 --> 00:05:53.199 +Here we see + +00:05:53.199 --> 00:05:54.800 +it's not going to warn me here + +00:05:54.800 --> 00:05:55.759 +because it doesn't know + +00:05:55.759 --> 00:05:57.600 +that `ivy-make-magic-action` + +00:05:57.600 --> 00:05:58.400 +takes a function, + +00:05:58.400 --> 00:06:02.319 +but it's a pretty good guess that it does. + +06:12.319 --> 06:14.479 +And here's some more. + +06:14.479 --> 06:16.080 +What else do we have? + +06:16.080 --> 06:19.120 +Is that all we have here? + +06:19.120 --> 06:21.440 +Well, looks like it. Oh, I see a few... + +06:21.440 --> 06:27.680 +a few more here... + +06:27.680 --> 06:30.639 +and one more. + +06:30.639 --> 06:33.039 +And oh, this is more interesting. + +06:33.039 --> 06:35.280 +So here we have a use of `defadvice`, + +06:35.280 --> 06:37.440 +so if we go back + +06:37.440 --> 06:38.479 +to the beginning of the file, + +06:40.720 --> 06:42.880 +we see that it actually depends + +06:42.880 --> 00:06:47.360 +on Emacs 24.5, so it actually has + +06:47.360 --> 00:06:49.280 +the new advice system available + +00:06:49.280 --> 00:06:51.520 +without having to add any dependency, + +00:06:51.520 --> 00:06:53.599 +so there's really no good reason + +00:06:53.599 --> 00:06:54.880 +to keep this. + +06:54.880 --> 00:06:56.160 +So we just convert this + +00:06:56.160 --> 00:06:58.560 +to an `advice-add`, + +06:58.560 --> 00:06:59.840 +so it just says, you know, + +00:06:59.840 --> 00:07:02.319 +this is the function that's advised. + +07:02.319 --> 07:04.560 +This was a `before` advice. + +07:04.560 --> 07:05.500 +The `before` advice, sometimes, + +07:05.500 --> 07:08.479 +when we convert it to `advice-add`, + +07:08.479 --> 07:11.199 +need to be converted to `around` advice. + +07:11.199 --> 07:13.280 +This is when the function + +07:13.280 --> 07:15.840 +looks or modifies the argument. + +07:15.840 --> 07:18.639 +In this case, if I look at it, + +07:18.639 --> 07:20.319 +I see it doesn't seem to be using + +07:20.319 --> 07:21.280 +the arguments at all. + +07:21.280 --> 00:07:25.280 +So I'm just going to keep it + +00:07:25.280 --> 00:07:27.520 +as a `before` advice. + +07:27.520 --> 00:07:28.672 +And we have to give it a name. + +00:07:28.672 --> 00:07:30.880 +Well, we don't really have to, + +07:30.880 --> 07:32.800 +but it's convenient to give it a name + +07:32.800 --> 07:34.800 +to the new function. + +07:34.800 --> 00:07:36.880 +So here, they actually had + +00:07:36.880 --> 00:07:38.080 +given a name to the advice, + +00:07:38.080 --> 00:07:39.599 +so we're going to keep it, + +00:07:39.599 --> 00:07:41.440 +and indeed it's the only function. + +00:07:41.440 --> 00:07:43.360 +This name is not used as a function, + +00:07:43.360 --> 00:07:44.160 +so we can use it + +00:07:44.160 --> 00:07:46.960 +as the name of the function. + +07:46.960 --> 00:07:49.039 +I'm going to add a dash here + +00:07:49.039 --> 00:07:51.120 +because I think this function + +00:07:51.120 --> 00:07:53.039 +is really fundamentally + +00:07:53.039 --> 00:07:54.639 +an internal function. + +07:54.639 --> 07:56.720 +So here I just said I add the advice, + +07:56.720 --> 07:58.000 +but I still need to actually + +07:58.000 --> 07:59.800 +define the function. + +08:02.879 --> 00:08:04.160 +So that's what I do here, + +00:08:04.160 --> 00:08:06.500 +and we need here to list the arguments + +08:06.500 --> 08:08.240 +that are going to be taken. + +08:08.240 --> 00:08:09.199 +I don't know what these are, + +00:08:09.199 --> 00:08:10.960 +but I know we're not using them, + +00:08:10.960 --> 00:08:13.759 +so we'll just accept anything, + +08:13.759 --> 08:16.560 +and that will do the trick. + +08:16.560 --> 08:19.199 +It's a future-proof as well, + +08:19.199 --> 08:22.240 +so that should work. + +08:22.240 --> 00:08:24.160 +Oh, here we have another, so it's + +00:08:24.160 --> 00:08:29.919 +basically the same story, I think. + +08:29.919 --> 00:08:31.599 +It's a `before` advice as well. + +00:08:31.599 --> 00:08:32.959 +It doesn't seem to be using + +00:08:32.959 --> 00:08:35.599 +the argument at all, + +08:35.599 --> 00:08:38.596 +and let's see if this name is not taken. + +00:08:38.596 --> 00:08:43.360 +Yeah, good, so we can just do the same: + +08:43.360 --> 08:46.880 +turn this into an `advice-add`... + +08:46.880 --> 08:48.300 +`before`... + +08:53.040 --> 08:55.000 +I just add a dash here. + +09:02.480 --> 00:09:05.440 +And same thing-- + +00:09:05.440 --> 00:09:06.959 +a function that just takes... + +09:06.959 --> 09:08.240 +because I don't know which arguments + +09:08.240 --> 09:10.480 +these are so... + +09:10.480 --> 09:14.640 +I think that should do the trick. + +09:14.640 --> 00:09:16.080 +Actually, we see that this function + +00:09:16.080 --> 00:09:18.560 +is very similar to the other one. + +09:18.560 --> 09:23.000 +Let's look at the two side-by-side... + +09:31.519 --> 00:09:33.055 +...it really is-- + +00:09:33.055 --> 00:09:36.097 +oh, it's not exactly identical... + +00:09:36.097 --> 00:09:39.120 +it's, you know, we could try + +09:39.120 --> 09:41.680 +to merge them into a single function, + +09:41.680 --> 09:43.279 +but it's probably not worth the trouble + +09:43.279 --> 09:45.920 +so we can keep it this way. + +09:45.920 --> 09:48.720 +Okay, next warning: an `eval` again, + +09:48.720 --> 09:50.640 +so I could just add `t` here, + +09:50.640 --> 00:09:55.120 +but if you look at it a bit more, + +00:09:55.120 --> 00:09:56.000 +you see that the code + +00:09:56.000 --> 00:09:57.760 +we're going to evaluate + +09:57.760 --> 00:09:59.279 +using either lexical scoping + +00:09:59.279 --> 00:10:00.560 +or dynamic scoping + +00:10:00.560 --> 00:10:03.440 +is actually just evaluating a symbol, + +00:10:03.440 --> 00:10:06.240 +since we just call an `intern` here. + +10:06.240 --> 00:10:07.839 +So instead of replacing this + +00:10:07.839 --> 00:10:09.279 +by adding an argument, + +00:10:09.279 --> 00:10:11.680 +I'm just going to call `symbol-value` + +00:10:11.680 --> 00:10:12.640 +because that's exactly + +00:10:12.640 --> 00:10:14.480 +what we need to do here, right. + +00:10:14.480 --> 00:10:16.320 +I call this "strength reduction," + +00:10:16.320 --> 00:10:17.200 +and I'm using + +00:10:17.200 --> 00:10:19.680 +a more primitive function instead, + +00:10:19.680 --> 00:10:23.200 +which does just what we need, + +10:23.200 --> 10:25.680 +and this one knows that it has to be + +10:25.680 --> 00:10:30.640 +accessed by dynamic scoping, of course. + +10:30.640 --> 00:10:32.959 +Here I have a `kmacro-ring`, + +00:10:32.959 --> 00:10:35.600 +so here I have a function that uses-- + +10:35.600 --> 00:10:37.360 +`kmacro-ring` comes from + +00:10:37.360 --> 00:10:39.760 +the `kmacro` package, obviously, + +10:39.760 --> 10:41.600 +and we probably don't want to + +10:41.600 --> 10:42.959 +`require` `kmacro` package + +10:42.959 --> 00:10:48.560 +all over the place in `counsel` itself, + +10:48.560 --> 00:10:50.240 +because `counsel` can be used + +00:10:50.240 --> 00:10:53.279 +without `kmacro`. + +10:53.279 --> 00:10:55.200 +So I think we're just going to add + +00:10:55.200 --> 00:11:04.000 +a `defvar` to silence the warning. + +11:05.519 --> 00:11:10.720 +And we have several more. So we have + +11:10.720 --> 00:11:14.000 +`initial-counter-value`. (Sorry.) + +11:20.480 --> 11:23.360 +We have `kmacro-counter`. + +11:23.360 --> 11:25.760 +Do we have more? + +11:25.760 --> 11:28.560 +Oh, yes, we do. + +11:28.560 --> 11:35.040 +We have `kmacro-counter-value-start` + +11:35.040 --> 11:40.839 +and `kmacro-counter-format-start`. + +11:40.839 --> 11:43.920 +Okay. + +11:45.040 --> 11:50.160 +I hope this is it. + +11:50.160 --> 11:52.880 +`kmacro-ring`, `counter`, `ring`... + +11:52.880 --> 11:54.959 +blah blah blah. + +11:54.959 --> 00:12:00.240 +Here we have another one, `quote`. + +12:00.240 --> 12:03.279 +Here we have another hash missing. + +12:03.279 --> 12:06.079 +It's not missing... + +12:06.079 --> 12:08.000 +but same thing here. + +12:12.079 --> 00:12:16.560 +Okay, this is a function from `kmacro`. + +12:16.560 --> 00:12:18.079 +We could declare it + +00:12:18.079 --> 00:12:20.880 +just to silence the warning + +12:20.880 --> 00:12:22.320 +although we don't actually... + +00:12:22.320 --> 00:12:24.480 +normally, when we declare such things-- + +12:24.480 --> 00:12:25.279 +same thing with variables-- + +00:12:25.279 --> 00:12:27.300 +we should try to make sure that indeed + +12:27.300 --> 12:28.760 +by the time the code is executed, + +12:28.760 --> 12:30.800 +the function will be available, + +12:30.800 --> 00:12:32.800 +and then very often is + +00:12:32.800 --> 00:12:34.320 +because there's a `require` + +00:12:34.320 --> 00:12:35.680 +sometimes inside a function, + +00:12:35.680 --> 00:12:36.399 +and so we should put + +00:12:36.399 --> 00:12:37.680 +the `declare` function + +00:12:37.680 --> 00:12:39.920 +right after the `require`, + +00:12:39.920 --> 00:12:41.839 +but I don't think it's the case here. + +12:41.839 --> 00:12:46.399 +So I'm just going to to add this. + +12:46.399 --> 12:49.040 +I know this comes from `kmacro`, + +12:49.040 --> 00:12:53.500 +and I could actually check the arguments. + +12:56.320 --> 00:12:58.480 +It's just taking an optional argument + +00:12:58.480 --> 00:13:00.880 +so I'm going to put it there, + +00:13:00.880 --> 00:13:06.720 +so we have it complete. + +13:06.720 --> 13:10.800 +Okay, we can just recompile, + +13:10.800 --> 00:13:14.800 +see what is left + +00:13:14.800 --> 00:13:17.760 +from those warnings we've fixed, + +00:13:17.760 --> 00:13:21.360 +and we may have new warnings, in any case, + +00:13:21.360 --> 00:13:25.440 +because especially when we add the hashes, + +00:13:25.440 --> 00:13:29.519 +it tends to give us more warnings. + +13:29.519 --> 00:13:31.200 +So we have two more functions + +00:13:31.200 --> 00:13:34.560 +which are not known. + +13:34.560 --> 13:39.440 +You can just add them here... + +13:39.440 --> 13:44.720 +`set-format "kmacro"` + +13:44.720 --> 13:48.160 +and same thing for `set-counter`. + +13:48.160 --> 13:50.000 +Okay, whatever. + +13:54.959 --> 00:13:57.120 +This just takes a `format` argument, + +00:13:57.120 --> 00:14:05.920 +and this one just takes an `arg` argument. + +14:05.920 --> 14:10.800 +Okay, so let's see what this says now. + +14:10.800 --> 14:15.519 +Hopefully, there's no warnings anymore. + +14:15.519 --> 14:17.839 +We're done. Okay! + +14:17.839 --> 00:14:20.079 +Okay, the last one we're going to see + +00:14:20.079 --> 00:14:23.440 +is in `enwc`, I saw the other day... + +14:23.440 --> 14:26.240 +I think I have it here... + +14:27.760 --> 14:29.680 +here we go, yes... + +14:29.680 --> 14:32.800 +so `enwc` is an interesting package here + +14:32.800 --> 14:35.680 +because it has-- as you can see it has-- + +14:35.680 --> 14:37.760 +it's lexical binding, + +14:37.760 --> 14:39.760 +but actually some of the files in it + +14:39.760 --> 14:42.320 +do not use lexical binding, + +14:42.320 --> 14:44.320 +so it has been partly converted + +14:44.320 --> 14:46.160 +but not completely. + +14:46.160 --> 00:14:49.920 +So here I'm going to + +00:14:49.920 --> 00:14:54.160 +enable lexical binding. + +14:54.160 --> 14:58.880 +I have also, I think, in `cm`... + +14:58.880 --> 15:01.199 +yes... + +15:01.199 --> 15:04.000 +so I enable it here, + +15:04.000 --> 15:07.360 +and also, I think, `test`. + +15:07.360 --> 00:15:09.360 +The test files are often + +00:15:09.360 --> 00:15:11.839 +somewhat problematic + +00:15:11.839 --> 00:15:15.199 +because very often they're not quite + +15:15.199 --> 15:18.880 +as heavily tested themselves, actually, + +15:18.880 --> 00:15:20.320 +or they only run + +00:15:20.320 --> 00:15:22.160 +in very specific contexts, + +00:15:22.160 --> 00:15:24.399 +and so they may have problems + +00:15:24.399 --> 00:15:27.360 +with missing `requires` or using packages + +00:15:27.360 --> 00:15:29.199 +which are not explicitly in the dependencies + +15:29.199 --> 15:31.279 +and those kinds of things. + +15:31.279 --> 15:33.360 +I think this is not the case here, + +15:33.360 --> 15:35.440 +but we'll see. + +15:35.440 --> 15:38.880 +`enwc`... + +15:38.880 --> 15:42.320 +Yes, I want to save this one and that one. + +15:42.320 --> 15:45.000 +Let's see what it says. + +15:47.199 --> 15:51.440 +Okay, unused lexical variable `x`... + +15:51.440 --> 15:52.240 +`x`... + +15:52.240 --> 15:57.120 +Yes, so here we have an unused variable, + +15:57.120 --> 15:58.320 +and indeed, it's not used. + +15:58.320 --> 16:00.880 +It probably had to be named before + +16:00.880 --> 16:04.079 +because it was... + +16:04.079 --> 00:16:05.120 +with dynamic scoping, + +00:16:05.120 --> 00:16:06.399 +the `dotimes` requires + +00:16:06.399 --> 00:16:08.160 +the variable to be named, actually, + +00:16:08.160 --> 00:16:10.399 +because it's used internally somehow, + +16:10.399 --> 00:16:11.600 +but with lexical scoping, + +00:16:11.600 --> 00:16:12.320 +that's not the case, + +00:16:12.320 --> 00:16:14.079 +so we can just put an underscore. + +16:14.079 --> 00:16:15.199 +I'm going to change this + +00:16:15.199 --> 00:16:16.880 +because I really don't like + +16:16.880 --> 16:19.000 +this three-part `dotimes`. + +16:19.000 --> 00:16:21.360 +I prefer to have + +00:16:21.360 --> 00:16:23.040 +the return value at the end. + +16:23.040 --> 00:16:26.480 +It's sort of stashed hidden in the middle. + +16:26.480 --> 16:29.680 +That's just a personal preference. + +16:29.680 --> 16:31.920 +Okay, what else... we have a `widget`. + +16:31.920 --> 16:34.000 +Okay, this argument here says that + +16:34.000 --> 16:37.000 +it's not used, so if we look at... + +16:44.320 --> 00:16:47.040 +We were here, right? Yes. Right here. + +00:16:47.040 --> 00:16:50.480 +Indeed, `widget` is really not used. + +16:50.480 --> 16:51.230 +(Sorry.) + +16:53.600 --> 00:16:55.279 +Here's what I get for using + +00:16:55.279 --> 00:16:58.320 +a somewhat vanilla configuration of Emacs, + +16:58.320 --> 17:01.279 +compared to the one I use... + +17:01.279 --> 17:04.000 +the personally tricked one. + +17:04.000 --> 17:05.439 +Actually, I can... + +17:05.439 --> 17:07.919 +so we can just mark this argument + +17:07.919 --> 17:09.360 +as unused, + +17:09.360 --> 17:11.199 +and we don't want to remove the argument + +17:11.199 --> 00:17:12.480 +probably, or maybe we could; + +00:17:12.480 --> 00:17:15.679 +we could see where the function is used, + +17:15.679 --> 00:17:18.542 +and here we see that it's passed + +00:17:18.542 --> 00:17:20.959 +to a higher-order function, + +17:20.959 --> 17:24.480 +basically, so it's going to be... + +17:24.480 --> 00:17:25.360 +We can't really change + +00:17:25.360 --> 00:17:25.760 +the calling convention + +17:25.760 --> 17:27.120 +so we have to mark the argument + +17:27.120 --> 17:29.600 +as being just an unused argument, + +17:29.600 --> 17:34.000 +but we're going to still receive it. + +17:34.000 --> 00:17:35.360 +And here it says same thing: + +00:17:35.360 --> 00:17:38.240 +that `widget` is not used in this function. + +17:38.240 --> 17:40.000 +Let's take a look at the function. + +17:40.000 --> 17:42.400 +Indeed it seems it's not used, + +17:42.400 --> 17:44.000 +and so we're just going to mark it + +17:44.000 --> 17:46.480 +as unused. + +17:46.480 --> 00:17:48.320 +This is the part of the conversion + +00:17:48.320 --> 00:17:49.200 +to lexical scoping + +00:17:49.200 --> 00:17:51.280 +that's somewhat tricky sometimes + +00:17:51.280 --> 00:17:53.760 +because we don't really know + +00:17:53.760 --> 00:17:56.240 +whether this variable should be using + +00:17:56.240 --> 00:17:58.559 +lexical scoping or dynamic scoping. + +17:58.559 --> 00:18:00.480 +The fact that it's not used + +00:18:00.480 --> 00:18:02.320 +is a hint that there's probably + +00:18:02.320 --> 00:18:03.679 +something going on, + +18:03.679 --> 00:18:04.960 +so either it's not used + +00:18:04.960 --> 00:18:06.400 +because it should be using + +00:18:06.400 --> 00:18:07.200 +dynamic scoping-- + +00:18:07.200 --> 00:18:08.080 +it is going to be used + +00:18:08.080 --> 00:18:10.480 +by some other code somewhere else-- + +18:10.480 --> 00:18:11.840 +or it's really not used + +00:18:11.840 --> 00:18:14.000 +because it's just not used, right, + +00:18:14.000 --> 00:18:16.320 +and so we need to distinguish the two, + +00:18:16.320 --> 00:18:20.880 +and for that, I basically use + +00:18:20.880 --> 00:18:22.240 +my own judgment. + +18:22.240 --> 18:24.880 +This is based typically on the fact that + +18:24.880 --> 00:18:27.760 +this is just a very short name, + +00:18:27.760 --> 00:18:32.000 +and most local identifiers use short names, + +18:32.000 --> 18:34.400 +whereas item values used for dynamic scoping + +18:34.400 --> 18:36.720 +typically have a package prefix + +18:36.720 --> 00:18:37.679 +or something like this. + +00:18:37.679 --> 00:18:38.960 +So the fact that it's a short name + +00:18:38.960 --> 00:18:40.880 +gives me a good idea. + +18:40.880 --> 00:18:41.520 +Here in this case, + +00:18:41.520 --> 00:18:42.640 +I actually look at the code, + +00:18:42.640 --> 00:18:45.600 +and we see that there's nothing in here + +18:45.600 --> 00:18:47.039 +that may actually refer + +00:18:47.039 --> 00:18:48.080 +to this variable `widget`, + +00:18:48.080 --> 00:18:49.280 +so I think it's safe, + +18:49.280 --> 00:18:51.360 +but in the general case, + +00:18:51.360 --> 00:18:54.400 +we may look here and be surprised, + +18:54.400 --> 00:18:55.760 +or, you know, you may call out + +00:18:55.760 --> 00:18:58.320 +the functions which may themselves end up + +18:58.320 --> 19:00.080 +referring to this variable. + +19:00.080 --> 19:02.640 +So sometimes we need to investigate a + +19:02.640 --> 19:03.840 +little more. + +19:03.840 --> 19:05.919 +We are most of the time not completely sure + +19:05.919 --> 19:07.520 +whether the result is correct or not, + +19:07.520 --> 00:19:09.520 +of course, so the other thing + +00:19:09.520 --> 00:19:10.640 +you may want to check + +00:19:10.640 --> 00:19:12.160 +is also uses of things + +00:19:12.160 --> 00:19:14.400 +like `eval` or `symbol-value`. + +19:14.400 --> 19:17.200 +So it's often a good idea to search, + +19:17.200 --> 00:19:18.799 +and you do a search of `eval`, + +00:19:18.799 --> 00:19:21.490 +and you see here it's using `eval`. + +00:19:21.490 --> 00:19:24.160 +Hmmm... Okay, so what does this `eval` do? + +19:24.160 --> 00:19:25.760 +It's evaluating expressions + +00:19:25.760 --> 00:19:28.240 +that appear in `args` here + +19:28.240 --> 19:31.840 +so you can see where those args come from, + +19:31.840 --> 00:19:35.120 +and we see here, these are expressions + +00:19:35.120 --> 00:19:36.840 +that don't do anything very special. + +19:36.840 --> 19:41.520 +It's just using `make-supplicant-choice`, + +19:41.520 --> 19:44.960 +and `make-supplicant-choice` itself + +19:44.960 --> 19:47.120 +just doesn't refer to `widget`, for example, + +19:47.120 --> 19:50.000 +so you know we should be safe, + +19:50.000 --> 19:52.559 +but while I'm here... + +19:52.559 --> 19:53.840 +okay, well, then we can do that later. + +19:53.840 --> 19:55.679 +Well, that's actually the next warning, + +19:55.679 --> 00:19:58.080 +exactly. So here we see that this is + +00:19:58.080 --> 00:20:00.000 +using the dynamically-scoped dialect, + +00:20:00.000 --> 00:20:02.799 +so we convert it to lexical-scoped. + +20:02.799 --> 20:04.559 +Of course, this may introduce errors, + +20:04.559 --> 20:07.200 +but we hope it doesn't. + +20:07.200 --> 20:08.880 +And actually, it was a good change here, + +20:08.880 --> 20:12.080 +because if you see again, + +20:12.080 --> 00:20:14.240 +this actually evals expressions + +00:20:14.240 --> 00:20:16.159 +that appear here in `args`, + +20:16.159 --> 20:18.480 +and so these are expressions + +20:18.480 --> 20:21.039 +that are passed here. + +20:21.039 --> 20:23.679 +So this expression here used to be + +20:23.679 --> 00:20:24.480 +evaluated with dynamic scoping, + +00:20:24.480 --> 00:20:28.000 +even though it appears to be normal code + +00:20:28.000 --> 00:20:29.760 +within this file, which says + +00:20:29.760 --> 00:20:32.559 +it's using lexical scoping, + +20:32.559 --> 20:34.400 +and so there are some remnants + +20:34.400 --> 20:36.640 +of dynamic scoping all over the place + +20:36.640 --> 00:20:37.840 +in Emacs still, because we have + +00:20:37.840 --> 00:20:43.679 +those calls of `eval` with a nil argument. + +20:44.880 --> 20:47.039 +Here we have `cons`... + +20:47.039 --> 20:50.400 +that needs to be `hash quoted`. + +20:52.400 --> 00:20:54.080 +Oh, and we have a reference + +00:20:54.080 --> 00:20:56.720 +to this variable `enwc-edit-id'. + +00:20:56.720 --> 00:20:57.520 +So this is clearly + +00:20:57.520 --> 00:21:00.400 +a dynamic-scoped variable. + +21:00.400 --> 21:02.000 +We can either add a `defvar` + +21:02.000 --> 21:03.440 +to silence the warning, + +21:03.440 --> 00:21:06.799 +or maybe we can `require` the package. + +21:06.799 --> 21:10.080 +The file that defines it... + +21:14.080 --> 21:17.360 +So let's see where it's defined. + +21:17.360 --> 21:21.200 +Here it's defined in `enwc.el`, + +21:21.200 --> 00:21:23.440 +so I'm going to try just to add + +00:21:23.440 --> 00:21:25.039 +the dependency. + +21:25.039 --> 00:21:27.840 +I'm going to `require` here. This is risky. + +21:27.840 --> 21:30.159 +We'll see when we compile a file later, + +21:30.159 --> 21:32.320 +we may get a circular dependency + +21:32.320 --> 21:34.720 +because of it. + +21:34.720 --> 21:36.320 +If that's the case, we're going to + +21:36.320 --> 00:21:38.320 +have to remove this `require` + +00:21:38.320 --> 00:21:42.000 +and instead put `defvar`s. + +21:42.000 --> 21:42.559 +Sometimes it's worth actually + +21:42.559 --> 21:44.640 +looking further at the various files + +21:44.640 --> 00:21:48.080 +to see how to redefine the dependencies + +21:48.080 --> 21:49.840 +to break those circular dependencies, + +21:49.840 --> 21:52.320 +but it's often not really + +21:52.320 --> 21:54.720 +worth the trouble. + +21:55.679 --> 00:21:58.400 +Oh, no, that's not what-- + +00:21:58.400 --> 00:22:01.440 +I'm not going to the right place... + +00:22:01.440 --> 00:22:07.039 +Here I was. So here `edit-map`. + +22:07.039 --> 22:09.760 +Well, we can probably... + +22:09.760 --> 22:12.159 +it may disappear or... + +22:12.159 --> 22:13.760 +oh, I see. + +22:13.760 --> 22:16.320 +Okay, so this `edit-map` actually is + +22:16.320 --> 22:18.559 +defined in this very file. + +22:18.559 --> 00:22:20.240 +It's just that it's defined later. + +00:22:20.240 --> 00:22:21.600 +So all we need to do + +00:22:21.600 --> 00:22:24.320 +is to move this definition + +00:22:24.320 --> 00:22:27.200 +to before its first use, + +22:27.200 --> 22:28.960 +since otherwise it's going to be taken + +22:28.960 --> 22:33.520 +as lexically-scoped, which we don't want. + +22:33.520 --> 22:35.360 +And while I'm here, I see this `copy-keymap`. + +22:35.360 --> 22:38.400 +I don't like `copy-keymap`, + +22:38.400 --> 22:40.960 +so I'm going to change this + +22:40.960 --> 22:44.080 +to a normal keymap, + +22:44.080 --> 22:46.159 +and then I'm just going to use + +22:46.159 --> 22:50.080 +`set-keymap-parent` instead of `copy-keymap` + +22:50.080 --> 00:22:51.600 +to get basically the same result, + +00:22:51.600 --> 00:22:55.280 +but without having copied anything. + +22:55.280 --> 22:57.760 +And this one will disappear... + +22:57.760 --> 23:00.240 +this one as well-- or should hopefully, + +23:00.240 --> 23:03.360 +thanks to the `require`. + +23:03.360 --> 23:09.840 +Here we have a `hash` missing, + +23:09.840 --> 00:23:11.840 +and we have some functions + +00:23:11.840 --> 00:23:14.000 +which are unknown, + +23:14.000 --> 00:23:14.666 +so let's see... + +00:23:14.666 --> 00:23:18.240 +Where is this function defined? + +23:18.240 --> 23:21.679 +Nowhere. Huh, wonderful, okay. + +23:21.679 --> 00:23:25.200 +So we'll just leave it like it is, + +00:23:25.200 --> 00:23:27.120 +and that's going to be + +00:23:27.120 --> 00:23:31.360 +for the author of the package to fix. + +23:31.360 --> 23:37.120 +How about this one? + +23:37.120 --> 23:40.240 +Oh, okay, so it's defined in `enwc.el` + +23:40.240 --> 00:23:41.679 +so presumably, + +00:23:41.679 --> 00:23:44.559 +this is going to disappear as well. + +23:50.159 --> 23:51.030 +One more... + +23:56.159 --> 23:58.640 +Okay, so this one + +23:58.640 --> 23:59.919 +is just like the previous one. + +23:59.919 --> 24:04.000 +We're going to leave it at that. + +24:04.000 --> 24:06.720 +And this is it! Huh, wonderful. + +24:06.720 --> 24:10.000 +So let's recompile. + +24:16.080 --> 24:23.520 +Oh, we have a warning for `fin`. + +24:25.679 --> 00:24:28.640 +This variable seems not to be used + +00:24:28.640 --> 00:24:32.000 +anywhere in the file, so we're just + +24:32.000 --> 00:24:33.440 +going to remove it. + +00:24:33.440 --> 00:24:34.880 +I leave it there just in case + +00:24:34.880 --> 00:24:36.000 +someone needs later on + +00:24:36.000 --> 00:24:37.679 +to look for a `fin` variable + +00:24:37.679 --> 00:24:39.760 +to see where it used to be. + +24:39.760 --> 24:41.600 +Again, you know, maybe it's actually used... + +24:41.600 --> 24:43.519 +yeah, dynamic scoping somehow, + +24:43.519 --> 24:46.159 +but given the short name, + +24:46.159 --> 24:48.960 +I presume this is not the case. + +24:48.960 --> 24:51.200 +Here, oh, that's the code removed + +24:51.200 --> 24:52.559 +that had a hash missing. + +24:52.559 --> 24:54.159 +That's the one that's not defined. + +24:54.159 --> 24:56.799 +This one is not defined, + +24:56.799 --> 24:58.000 +and this is it. + +24:58.000 --> 25:03.039 +Let's make a last recompilation + +25:03.039 --> 25:06.080 +to see if we missed yet something else. + +25:06.080 --> 25:07.919 +Nope, and that's it, okay. + +25:07.919 --> 25:11.200 +Well, here we go; we're done. + +25:11.200 --> 00:25:14.240 +Okay so this was it. + +00:25:14.240 --> 00:25:15.440 +You've seen, I think, + +25:15.440 --> 25:18.000 +pretty much examples of all of those, + +25:18.000 --> 25:20.159 +and I hope you enjoyed it. + +25:20.960 --> 25:22.580 +Lessons to take home: + +25:22.580 --> 25:23.919 +use the byte compiler. + +25:23.919 --> 25:26.000 +You can also use `flymake-mode` instead. + +25:26.000 --> 00:25:31.600 +I recommend enabling it as much as you can, + +25:31.600 --> 25:33.520 +and head the warnings. + +25:33.520 --> 25:35.440 +Follow the warnings. Try to fix them. + +25:35.440 --> 25:37.200 +If you can fix all of the warnings, + +25:37.200 --> 00:25:38.080 +it's always much better, + +00:25:38.080 --> 00:25:39.200 +because then the new warnings + +00:25:39.200 --> 00:25:40.960 +really show up. + +25:40.960 --> 25:42.880 +And once you've done it, it's really + +25:42.880 --> 00:25:44.559 +kind of-- because there's always + +00:25:44.559 --> 00:25:46.799 +new things coming up. + +25:46.799 --> 25:48.799 +And I think this is it. + +25:48.799 --> 00:25:50.720 +I hope you liked it, and thank you + +00:25:50.720 --> 00:25:56.000 +for attending this presentation. Bye. + +00:25:56.000 --> 00:25:57.000 +[captions by Hannah Miller] |