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+WEBVTT
+
+00:00:01.839 --> 00:00:04.160
+hello EmacsConf
+
+00:00:04.160 --> 00:00:05.759
+thanks very much first of all to the
+
+00:00:05.759 --> 00:00:07.200
+organizers of the conference
+
+00:00:07.200 --> 00:00:09.440
+and to the audience who I hope is out
+
+00:00:09.440 --> 00:00:10.480
+there somewhere
+
+00:00:10.480 --> 00:00:12.080
+uh for giving me this chance to talk
+
+00:00:12.080 --> 00:00:14.240
+about Emacs and some of my uh
+
+00:00:14.240 --> 00:00:16.560
+my poking around with Emacs lisp my name
+
+00:00:16.560 --> 00:00:18.480
+is eric abrahamson I'm not
+
+00:00:18.480 --> 00:00:20.960
+a professional programmer but I use
+
+00:00:20.960 --> 00:00:21.920
+Emacs all day
+
+00:00:21.920 --> 00:00:24.800
+every day for writing for translating
+
+00:00:24.800 --> 00:00:26.160
+for project management
+
+00:00:26.160 --> 00:00:28.160
+and most importantly for email which
+
+00:00:28.160 --> 00:00:29.199
+will be the
+
+00:00:29.199 --> 00:00:32.480
+subject of my talk today so I'm talking
+
+00:00:32.480 --> 00:00:35.440
+about object-oriented code in Emacs
+
+00:00:35.440 --> 00:00:38.320
+uh most famous possibly oldest
+
+00:00:38.320 --> 00:00:40.160
+definitely most notorious news reader
+
+00:00:40.160 --> 00:00:41.760
+slash Emacs client
+
+00:00:41.760 --> 00:00:44.320
+email client so in particular object
+
+00:00:44.320 --> 00:00:45.440
+oriented code
+
+00:00:45.440 --> 00:00:50.239
+in news why object-oriented code
+
+00:00:50.239 --> 00:00:51.920
+the way news works is it started off as
+
+00:00:51.920 --> 00:00:53.600
+a news reader so for access
+
+00:00:53.600 --> 00:00:57.039
+accessing nntp servers and later on grew
+
+00:00:57.039 --> 00:00:59.120
+a whole bunch of new functionality as a
+
+00:00:59.120 --> 00:01:01.039
+mail client so it can talk to imap
+
+00:01:01.039 --> 00:01:02.079
+servers
+
+00:01:02.079 --> 00:01:04.799
+mail dealer directories uh folders on
+
+00:01:04.799 --> 00:01:06.640
+your file system all kinds of stuff
+
+00:01:06.640 --> 00:01:08.400
+but it presents a unified interface to
+
+00:01:08.400 --> 00:01:09.760
+all those things so it's basically
+
+00:01:09.760 --> 00:01:11.040
+polymorphism
+
+00:01:11.040 --> 00:01:14.000
+one of the the basic fundamental
+
+00:01:14.000 --> 00:01:16.400
+principles of object oriented code so
+
+00:01:16.400 --> 00:01:18.720
+it's a good fit second reason is it
+
+00:01:18.720 --> 00:01:19.920
+already is
+
+00:01:19.920 --> 00:01:22.880
+object oriented and I'll get into what
+
+00:01:22.880 --> 00:01:23.759
+that means
+
+00:01:23.759 --> 00:01:27.280
+in a second so
+
+00:01:27.280 --> 00:01:28.640
+the background that you should know is
+
+00:01:28.640 --> 00:01:30.640
+that most of this code was written in
+
+00:01:30.640 --> 00:01:32.560
+the 90s
+
+00:01:32.560 --> 00:01:34.880
+Emacs lisp has only grown sort of
+
+00:01:34.880 --> 00:01:36.159
+official
+
+00:01:36.159 --> 00:01:38.640
+object orientation support libraries
+
+00:01:38.640 --> 00:01:41.200
+over the past 10 years or so
+
+00:01:41.200 --> 00:01:43.840
+from about 2010 to the present so what
+
+00:01:43.840 --> 00:01:44.799
+does
+
+00:01:44.799 --> 00:01:48.640
+news do so the basics of
+
+00:01:48.640 --> 00:01:50.560
+object orientation in most languages are
+
+00:01:50.560 --> 00:01:52.240
+you you define
+
+00:01:52.240 --> 00:01:53.759
+a class of some sort and then you
+
+00:01:53.759 --> 00:01:55.840
+instantiate that class and these
+
+00:01:55.840 --> 00:01:58.079
+class instances have two things they
+
+00:01:58.079 --> 00:02:00.320
+have data attributes or
+
+00:02:00.320 --> 00:02:01.759
+slots or members or whatever you're
+
+00:02:01.759 --> 00:02:04.799
+going to call them and they have
+
+00:02:04.799 --> 00:02:07.280
+methods which operate on individual
+
+00:02:07.280 --> 00:02:08.399
+instances
+
+00:02:08.399 --> 00:02:11.120
+so you could say that you create or
+
+00:02:11.120 --> 00:02:12.879
+instantiate an instance of a class in
+
+00:02:12.879 --> 00:02:13.920
+that instance
+
+00:02:13.920 --> 00:02:16.239
+owns two things that owns its set of
+
+00:02:16.239 --> 00:02:17.120
+attributes
+
+00:02:17.120 --> 00:02:20.239
+and it owns some methods which
+
+00:02:20.239 --> 00:02:23.280
+also work on the on the instance
+
+00:02:23.280 --> 00:02:26.720
+so both in nurse's existing code and in
+
+00:02:26.720 --> 00:02:29.040
+the more standard object oriented Emacs
+
+00:02:29.040 --> 00:02:30.080
+lisp libraries
+
+00:02:30.080 --> 00:02:32.480
+this relationship is turned on its head
+
+00:02:32.480 --> 00:02:34.080
+a little bit
+
+00:02:34.080 --> 00:02:37.599
+in that data slots and
+
+00:02:37.599 --> 00:02:40.239
+uh and instance methods are defined
+
+00:02:40.239 --> 00:02:41.360
+outside of the
+
+00:02:41.360 --> 00:02:42.959
+class or the instances themselves so
+
+00:02:42.959 --> 00:02:45.040
+they are top level definitions
+
+00:02:45.040 --> 00:02:46.879
+so we'll get to what that means in the
+
+00:02:46.879 --> 00:02:48.319
+in the newer libraries um
+
+00:02:48.319 --> 00:02:49.840
+in a bit but uh first I want to talk
+
+00:02:49.840 --> 00:02:51.760
+about how news does this and in order to
+
+00:02:51.760 --> 00:02:54.319
+do that we are going to go deep into
+
+00:02:54.319 --> 00:02:57.440
+the darkest corner of the new co source
+
+00:02:57.440 --> 00:02:59.879
+code tree to a library called
+
+00:02:59.879 --> 00:03:02.879
+nno.l very cryptically
+
+00:03:02.879 --> 00:03:05.040
+titled uh library and when we open it up
+
+00:03:05.040 --> 00:03:06.800
+we find
+
+00:03:06.800 --> 00:03:09.519
+a library with no code comments and
+
+00:03:09.519 --> 00:03:11.040
+almost no doc strings
+
+00:03:11.040 --> 00:03:12.800
+almost as if lars was a little ashamed
+
+00:03:12.800 --> 00:03:14.159
+not ashamed but knew he was doing
+
+00:03:14.159 --> 00:03:16.000
+something a little bit crazy
+
+00:03:16.000 --> 00:03:19.040
+and didn't want anyone to see so
+
+00:03:19.040 --> 00:03:21.040
+this file contains the the object
+
+00:03:21.040 --> 00:03:22.400
+oriented mechanism
+
+00:03:22.400 --> 00:03:24.480
+whereby you can define different kinds
+
+00:03:24.480 --> 00:03:25.760
+of back ends for news
+
+00:03:25.760 --> 00:03:27.280
+and then those back ends can be
+
+00:03:27.280 --> 00:03:29.760
+instantiated as individual
+
+00:03:29.760 --> 00:03:32.480
+servers and as you define these backends
+
+00:03:32.480 --> 00:03:33.360
+you're supposed to use
+
+00:03:33.360 --> 00:03:36.000
+two macros which you can see here one is
+
+00:03:36.000 --> 00:03:36.640
+called def
+
+00:03:36.640 --> 00:03:39.599
+vu and one is called defu and if you
+
+00:03:39.599 --> 00:03:41.280
+look at the definitions the definitions
+
+00:03:41.280 --> 00:03:43.280
+look pretty simple here def vu basically
+
+00:03:43.280 --> 00:03:45.440
+turns into a def var
+
+00:03:45.440 --> 00:03:49.040
+and foo turns into a defund
+
+00:03:49.040 --> 00:03:52.239
+and along with those basic definitions
+
+00:03:52.239 --> 00:03:55.760
+the library also does some registration
+
+00:03:55.760 --> 00:03:58.720
+memoization caching of those variables
+
+00:03:58.720 --> 00:04:00.080
+it saves them in the structure
+
+00:04:00.080 --> 00:04:01.840
+for later use so that we know that those
+
+00:04:01.840 --> 00:04:03.360
+are meant to be
+
+00:04:03.360 --> 00:04:05.280
+uh attributes and methods that are used
+
+00:04:05.280 --> 00:04:06.640
+with instances
+
+00:04:06.640 --> 00:04:08.000
+with server instances but you can see
+
+00:04:08.000 --> 00:04:09.280
+that there's no server instance
+
+00:04:09.280 --> 00:04:10.560
+definition here there's no
+
+00:04:10.560 --> 00:04:13.200
+like no nothing these are top level
+
+00:04:13.200 --> 00:04:14.239
+these are top level
+
+00:04:14.239 --> 00:04:18.160
+definitions so really data attributes
+
+00:04:18.160 --> 00:04:18.639
+for
+
+00:04:18.639 --> 00:04:22.000
+new servers and
+
+00:04:22.000 --> 00:04:23.840
+methods or functions that operate on
+
+00:04:23.840 --> 00:04:25.440
+those instances are completely
+
+00:04:25.440 --> 00:04:28.400
+separate mechanisms they don't really
+
+00:04:28.400 --> 00:04:29.600
+have anything to do with each other they
+
+00:04:29.600 --> 00:04:31.680
+don't belong to the same data structures
+
+00:04:31.680 --> 00:04:37.120
+so how do they work follow me
+
+00:04:37.120 --> 00:04:39.520
+aka methods and attributes these are all
+
+00:04:39.520 --> 00:04:41.360
+the things I just said
+
+00:04:41.360 --> 00:04:44.479
+so when you define a
+
+00:04:44.479 --> 00:04:48.560
+a backend type
+
+00:04:48.560 --> 00:04:51.199
+in noose what you get is this a
+
+00:04:51.199 --> 00:04:52.400
+definition a list
+
+00:04:52.400 --> 00:04:54.080
+and it'll say there is such a back end
+
+00:04:54.080 --> 00:04:55.520
+as nnml
+
+00:04:55.520 --> 00:04:58.880
+and these are its uh data attributes
+
+00:04:58.880 --> 00:04:59.520
+that any
+
+00:04:59.520 --> 00:05:01.840
+given instance can have and then these
+
+00:05:01.840 --> 00:05:02.960
+are
+
+00:05:02.960 --> 00:05:04.960
+the functions or methods that are
+
+00:05:04.960 --> 00:05:06.880
+defined to operate on
+
+00:05:06.880 --> 00:05:08.960
+an instance of this backend so a server
+
+00:05:08.960 --> 00:05:11.440
+that belongs to the nnml
+
+00:05:11.440 --> 00:05:13.360
+backend so at least we have this data
+
+00:05:13.360 --> 00:05:15.120
+here so that's that's handy we don't you
+
+00:05:15.120 --> 00:05:16.880
+don't really touch that that's like very
+
+00:05:16.880 --> 00:05:18.000
+very very deep
+
+00:05:18.000 --> 00:05:20.560
+um use code that doesn't really come up
+
+00:05:20.560 --> 00:05:22.560
+even as a
+
+00:05:22.560 --> 00:05:25.280
+even as a bug squasher or whatever we
+
+00:05:25.280 --> 00:05:26.479
+don't touch that very often but there
+
+00:05:26.479 --> 00:05:27.280
+they are and that's
+
+00:05:27.280 --> 00:05:30.400
+that's how they work now the next thing
+
+00:05:30.400 --> 00:05:32.080
+that obviously you want to know is okay
+
+00:05:32.080 --> 00:05:34.000
+where are if I've started up news where
+
+00:05:34.000 --> 00:05:35.039
+are my servers
+
+00:05:35.039 --> 00:05:37.199
+uh where are these server objects since
+
+00:05:37.199 --> 00:05:39.199
+this is object oriented
+
+00:05:39.199 --> 00:05:41.840
+programming and the weird thing that you
+
+00:05:41.840 --> 00:05:43.199
+will eventually
+
+00:05:43.199 --> 00:05:45.199
+figure out in some cases after years of
+
+00:05:45.199 --> 00:05:46.880
+poking around in the new source code
+
+00:05:46.880 --> 00:05:49.199
+is that servers do not exist in an
+
+00:05:49.199 --> 00:05:50.320
+ontological
+
+00:05:50.320 --> 00:05:53.440
+philosophical sense as objects the
+
+00:05:53.440 --> 00:05:55.440
+primary data structures of noose are
+
+00:05:55.440 --> 00:05:57.039
+groups
+
+00:05:57.039 --> 00:05:58.960
+and in sort of an object-oriented
+
+00:05:58.960 --> 00:06:00.720
+hierarchical you know mindset you'd
+
+00:06:00.720 --> 00:06:01.759
+think well
+
+00:06:01.759 --> 00:06:03.759
+groups belong to servers so servers must
+
+00:06:03.759 --> 00:06:05.759
+exist but they don't
+
+00:06:05.759 --> 00:06:08.000
+each group and here you can see some
+
+00:06:08.000 --> 00:06:09.360
+examples of groups
+
+00:06:09.360 --> 00:06:11.199
+these are basically the data structures
+
+00:06:11.199 --> 00:06:13.039
+that represent a group each group also
+
+00:06:13.039 --> 00:06:14.960
+has a little entry here that
+
+00:06:14.960 --> 00:06:17.039
+that tells you what server it belongs to
+
+00:06:17.039 --> 00:06:18.000
+and each group
+
+00:06:18.000 --> 00:06:20.479
+replicates that data uh saying which
+
+00:06:20.479 --> 00:06:23.120
+server it belongs to and so when
+
+00:06:23.120 --> 00:06:24.479
+nurse is going through doing its
+
+00:06:24.479 --> 00:06:26.160
+business uh trying to figure out what's
+
+00:06:26.160 --> 00:06:27.680
+like updating mail from the groups or
+
+00:06:27.680 --> 00:06:29.840
+whatever almost every time
+
+00:06:29.840 --> 00:06:31.600
+it will cycle through all the list of
+
+00:06:31.600 --> 00:06:32.960
+groups it'll
+
+00:06:32.960 --> 00:06:34.960
+it'll look at all the server definitions
+
+00:06:34.960 --> 00:06:36.720
+and it will categorize the groups by
+
+00:06:36.720 --> 00:06:38.160
+server
+
+00:06:38.160 --> 00:06:41.120
+which which is just weird because you're
+
+00:06:41.120 --> 00:06:42.160
+sort of looking for okay where does the
+
+00:06:42.160 --> 00:06:43.840
+server exist it doesn't exist it's put
+
+00:06:43.840 --> 00:06:44.479
+together
+
+00:06:44.479 --> 00:06:48.319
+every time uh out of out of code
+
+00:06:48.319 --> 00:06:50.400
+elsewhere in the news code base
+
+00:06:50.400 --> 00:06:51.840
+specifically from these group
+
+00:06:51.840 --> 00:06:54.080
+these group definitions and so this is
+
+00:06:54.080 --> 00:06:55.199
+very odd because
+
+00:06:55.199 --> 00:06:58.080
+in in some sense like here this one its
+
+00:06:58.080 --> 00:06:58.720
+server is
+
+00:06:58.720 --> 00:07:02.240
+nnml and an empty string so there's a
+
+00:07:02.240 --> 00:07:03.919
+certain sense here in which this server
+
+00:07:03.919 --> 00:07:04.479
+is not
+
+00:07:04.479 --> 00:07:06.400
+really an object at all what it is is a
+
+00:07:06.400 --> 00:07:07.759
+set of instructions for how to find
+
+00:07:07.759 --> 00:07:08.560
+messages
+
+00:07:08.560 --> 00:07:11.199
+and this set of instructions is go to
+
+00:07:11.199 --> 00:07:12.800
+the default place where the user
+
+00:07:12.800 --> 00:07:15.440
+might have their mail and expect to find
+
+00:07:15.440 --> 00:07:16.000
+messages
+
+00:07:16.000 --> 00:07:18.080
+there in an nml format which is
+
+00:07:18.080 --> 00:07:19.840
+basically just one message per
+
+00:07:19.840 --> 00:07:22.479
+um per file and any number of groups
+
+00:07:22.479 --> 00:07:23.840
+could have those same instructions uh
+
+00:07:23.840 --> 00:07:25.440
+but they're not it's not really a thing
+
+00:07:25.440 --> 00:07:26.720
+it's really just a
+
+00:07:26.720 --> 00:07:28.639
+it's more of a procedural instruction
+
+00:07:28.639 --> 00:07:30.240
+and on the other end of the spectrum you
+
+00:07:30.240 --> 00:07:31.919
+might have an nni map
+
+00:07:31.919 --> 00:07:33.599
+server which very much is a thing it has
+
+00:07:33.599 --> 00:07:35.840
+its own it has its own server its own
+
+00:07:35.840 --> 00:07:37.759
+port its own authentication
+
+00:07:37.759 --> 00:07:40.240
+system so some of the servers are more
+
+00:07:40.240 --> 00:07:41.360
+like things some of the servers are more
+
+00:07:41.360 --> 00:07:42.400
+like instructions
+
+00:07:42.400 --> 00:07:45.520
+as news works right now um these
+
+00:07:45.520 --> 00:07:47.280
+most of the servers are treated like
+
+00:07:47.280 --> 00:07:48.879
+just instruction sets
+
+00:07:48.879 --> 00:07:50.879
+and and there's no place where you can
+
+00:07:50.879 --> 00:07:53.120
+go and find them there's no one central
+
+00:07:53.120 --> 00:07:55.360
+uh variable that defines them all so how
+
+00:07:55.360 --> 00:07:56.160
+do the
+
+00:07:56.160 --> 00:07:57.520
+um so we'll talk about the methods in a
+
+00:07:57.520 --> 00:07:59.520
+second how do the data attributes work
+
+00:07:59.520 --> 00:08:02.639
+uh put very crudely um
+
+00:08:02.639 --> 00:08:04.479
+your servers when they're put together
+
+00:08:04.479 --> 00:08:05.919
+uh they are okay they are
+
+00:08:05.919 --> 00:08:08.080
+kept in a variable and it's called nno
+
+00:08:08.080 --> 00:08:08.960
+nno
+
+00:08:08.960 --> 00:08:11.120
+state a list and there's a concept to
+
+00:08:11.120 --> 00:08:12.960
+this of the current server
+
+00:08:12.960 --> 00:08:16.560
+so when we go here let's go back to
+
+00:08:16.560 --> 00:08:19.039
+our nnno definition a list so when we
+
+00:08:19.039 --> 00:08:20.560
+have an nnml
+
+00:08:20.560 --> 00:08:22.240
+server say we have one here and it's
+
+00:08:22.240 --> 00:08:24.400
+just this blank string
+
+00:08:24.400 --> 00:08:26.639
+these are all when you define that in
+
+00:08:26.639 --> 00:08:28.879
+your own uh server definition code
+
+00:08:28.879 --> 00:08:31.919
+you can put in different values for all
+
+00:08:31.919 --> 00:08:32.399
+of these
+
+00:08:32.399 --> 00:08:35.760
+various attributes and when noose comes
+
+00:08:35.760 --> 00:08:37.039
+when it comes time for news to operate
+
+00:08:37.039 --> 00:08:38.959
+on this server in particular ask it to
+
+00:08:38.959 --> 00:08:40.640
+you know open a group or get new mail
+
+00:08:40.640 --> 00:08:42.080
+what it will do is it will take
+
+00:08:42.080 --> 00:08:45.360
+that particular server's data from these
+
+00:08:45.360 --> 00:08:45.920
+symbols
+
+00:08:45.920 --> 00:08:47.600
+and it will copy all that information
+
+00:08:47.600 --> 00:08:49.600
+into the global devfars
+
+00:08:49.600 --> 00:08:51.760
+so for the time that you are operating
+
+00:08:51.760 --> 00:08:53.120
+on this particular server
+
+00:08:53.120 --> 00:08:55.920
+its individual data becomes the values
+
+00:08:55.920 --> 00:08:56.800
+of these global
+
+00:08:56.800 --> 00:08:59.360
+variables which when you realize what's
+
+00:08:59.360 --> 00:09:00.560
+happening is sort of terrifying you
+
+00:09:00.560 --> 00:09:02.080
+think oh my god
+
+00:09:02.080 --> 00:09:04.480
+but at the same time it's actually kind
+
+00:09:04.480 --> 00:09:05.760
+of impressive and it's amazing that it
+
+00:09:05.760 --> 00:09:07.279
+works as well as it does
+
+00:09:07.279 --> 00:09:09.120
+I'm actually a little bit in awe of the
+
+00:09:09.120 --> 00:09:10.880
+of the code in this in this library I
+
+00:09:10.880 --> 00:09:12.560
+think it's pretty impressive
+
+00:09:12.560 --> 00:09:15.760
+so as you nno change server
+
+00:09:15.760 --> 00:09:18.320
+uh this function here these values get
+
+00:09:18.320 --> 00:09:20.080
+copied into the global value into the
+
+00:09:20.080 --> 00:09:21.440
+global variables and then as you go on
+
+00:09:21.440 --> 00:09:22.399
+the next server
+
+00:09:22.399 --> 00:09:24.000
+that gets you know cleaned out and
+
+00:09:24.000 --> 00:09:26.399
+recopied there are a few
+
+00:09:26.399 --> 00:09:29.680
+um a few other slot types
+
+00:09:29.680 --> 00:09:32.000
+or attribute types which do because all
+
+00:09:32.000 --> 00:09:33.440
+of these attributes see they all start
+
+00:09:33.440 --> 00:09:34.720
+with the nml
+
+00:09:34.720 --> 00:09:37.920
+or in this case and in folder prefix
+
+00:09:37.920 --> 00:09:40.560
+but there are a few slot types that all
+
+00:09:40.560 --> 00:09:41.760
+servers need for
+
+00:09:41.760 --> 00:09:43.279
+for instance their most recent status
+
+00:09:43.279 --> 00:09:45.920
+message a status symbol like open denied
+
+00:09:45.920 --> 00:09:46.640
+whatever
+
+00:09:46.640 --> 00:09:48.080
+and that data is sort of scattered
+
+00:09:48.080 --> 00:09:49.680
+around the rest of the news
+
+00:09:49.680 --> 00:09:51.200
+code base in various variables or
+
+00:09:51.200 --> 00:09:53.440
+various places
+
+00:09:53.440 --> 00:09:55.440
+so that's that sort of just contributes
+
+00:09:55.440 --> 00:09:56.560
+to the confusion when you're trying to
+
+00:09:56.560 --> 00:09:57.360
+figure out why
+
+00:09:57.360 --> 00:10:00.720
+things are going wrong so that is our
+
+00:10:00.720 --> 00:10:03.839
+um nnoo which is and
+
+00:10:03.839 --> 00:10:05.440
+sort of how the attributes and these
+
+00:10:05.440 --> 00:10:07.360
+global variables work
+
+00:10:07.360 --> 00:10:09.120
+if we want to talk about defu and the
+
+00:10:09.120 --> 00:10:10.480
+methods we
+
+00:10:10.480 --> 00:10:20.800
+go to
+
+00:10:20.800 --> 00:10:23.200
+and so this is the place where all the
+
+00:10:23.200 --> 00:10:25.600
+server level methods are defined
+
+00:10:25.600 --> 00:10:27.200
+and what we have here are things like
+
+00:10:27.200 --> 00:10:29.279
+here's an example there's closed server
+
+00:10:29.279 --> 00:10:32.640
+this closed server is given a
+
+00:10:32.640 --> 00:10:36.320
+a server as a an argument
+
+00:10:36.320 --> 00:10:38.079
+it looks at the server and basically it
+
+00:10:38.079 --> 00:10:40.560
+finds the proper function to call on
+
+00:10:40.560 --> 00:10:42.079
+this particular server
+
+00:10:42.079 --> 00:10:45.120
+using the function new skip function by
+
+00:10:45.120 --> 00:10:45.600
+taking
+
+00:10:45.600 --> 00:10:48.959
+the sort of latter half of this function
+
+00:10:48.959 --> 00:10:49.760
+symbol
+
+00:10:49.760 --> 00:10:52.079
+and pasting it together with the symbol
+
+00:10:52.079 --> 00:10:53.440
+that represents the back end so
+
+00:10:53.440 --> 00:10:56.800
+if you were calling this on an nni map
+
+00:10:56.800 --> 00:10:59.600
+server your skip function would look at
+
+00:10:59.600 --> 00:11:01.279
+your imap server look at closed server I
+
+00:11:01.279 --> 00:11:02.240
+knew what
+
+00:11:02.240 --> 00:11:07.839
+it would come up with
+
+00:11:07.839 --> 00:11:10.240
+server sure enough there's an imac close
+
+00:11:10.240 --> 00:11:11.920
+server and it'll call this code and then
+
+00:11:11.920 --> 00:11:12.240
+it'll
+
+00:11:12.240 --> 00:11:14.000
+it'll go and do its other bookkeeping
+
+00:11:14.000 --> 00:11:15.279
+another sort of
+
+00:11:15.279 --> 00:11:18.320
+surrounding code and so that's not that
+
+00:11:18.320 --> 00:11:19.279
+actually works pretty well
+
+00:11:19.279 --> 00:11:22.640
+uh as as things go uh defu
+
+00:11:22.640 --> 00:11:24.959
+makes a record that this this function
+
+00:11:24.959 --> 00:11:26.800
+exists and nus gets function get
+
+00:11:26.800 --> 00:11:28.320
+function looks on that cache finds the
+
+00:11:28.320 --> 00:11:29.600
+function and calls it
+
+00:11:29.600 --> 00:11:30.959
+now what's particularly confusing is
+
+00:11:30.959 --> 00:11:32.560
+that you don't actually even have to use
+
+00:11:32.560 --> 00:11:33.360
+defu
+
+00:11:33.360 --> 00:11:35.519
+so whoever wrote and then mail gear
+
+00:11:35.519 --> 00:11:38.399
+which is a weird library
+
+00:11:38.399 --> 00:11:39.920
+said to heck with you I'm not using any
+
+00:11:39.920 --> 00:11:41.600
+of these
+
+00:11:41.600 --> 00:11:43.120
+any of this machinery I'm going to do it
+
+00:11:43.120 --> 00:11:45.839
+myself so we have
+
+00:11:45.839 --> 00:11:49.680
+def structs to hold uh the instance
+
+00:11:49.680 --> 00:11:52.320
+data and then we have just plain old
+
+00:11:52.320 --> 00:11:53.040
+defense
+
+00:11:53.040 --> 00:11:55.680
+for things like animal your close server
+
+00:11:55.680 --> 00:11:57.279
+request close all of these
+
+00:11:57.279 --> 00:11:59.279
+these server level uh variables and it
+
+00:11:59.279 --> 00:12:00.320
+just turns out that
+
+00:12:00.320 --> 00:12:03.360
+news in its belt and suspenders
+
+00:12:03.360 --> 00:12:05.839
+approach to uh to coding it'll actually
+
+00:12:05.839 --> 00:12:07.279
+just go out if it can't find
+
+00:12:07.279 --> 00:12:10.320
+the memoized function it'll just go out
+
+00:12:10.320 --> 00:12:12.160
+and say has anybody defined a function
+
+00:12:12.160 --> 00:12:14.240
+that looks like this pattern and then
+
+00:12:14.240 --> 00:12:16.000
+and then melder says yes I did and then
+
+00:12:16.000 --> 00:12:17.920
+we call it and then we go so it's just
+
+00:12:17.920 --> 00:12:19.920
+it's fine it works it just adds to the
+
+00:12:19.920 --> 00:12:21.440
+confusion why
+
+00:12:21.440 --> 00:12:24.240
+why does it work we don't know sometimes
+
+00:12:24.240 --> 00:12:25.440
+the only thing worse than not knowing
+
+00:12:25.440 --> 00:12:26.880
+why something doesn't work is
+
+00:12:26.880 --> 00:12:30.000
+not knowing why something does work um
+
+00:12:30.000 --> 00:12:30.560
+and then
+
+00:12:30.560 --> 00:12:31.920
+a last little bit I want to touch on
+
+00:12:31.920 --> 00:12:33.680
+here is inheritance which is another
+
+00:12:33.680 --> 00:12:35.440
+sort of cornerstone of object-oriented
+
+00:12:35.440 --> 00:12:38.480
+coding as far as I can tell only uh
+
+00:12:38.480 --> 00:12:40.160
+the only inheritance that goes on is in
+
+00:12:40.160 --> 00:12:41.920
+something called nn male
+
+00:12:41.920 --> 00:12:45.519
+which provides sort of common functions
+
+00:12:45.519 --> 00:12:48.399
+for back ends that keep their mail on
+
+00:12:48.399 --> 00:12:49.360
+your
+
+00:12:49.360 --> 00:12:52.000
+local machine and you can spool it you
+
+00:12:52.000 --> 00:12:53.680
+can delete it you can you know you own
+
+00:12:53.680 --> 00:12:55.440
+the messages it's not like an nntp
+
+00:12:55.440 --> 00:12:56.160
+server
+
+00:12:56.160 --> 00:12:59.040
+and so a lot of those male deer nnml
+
+00:12:59.040 --> 00:13:00.160
+whatever
+
+00:13:00.160 --> 00:13:02.959
+a lot of those have sort of similar code
+
+00:13:02.959 --> 00:13:04.079
+which they
+
+00:13:04.079 --> 00:13:07.600
+which they share via this nn mail
+
+00:13:07.600 --> 00:13:09.600
+you call it an abstract parent class I
+
+00:13:09.600 --> 00:13:12.959
+guess so if you have something like nnml
+
+00:13:12.959 --> 00:13:15.440
+it has a request scan uh when it goes
+
+00:13:15.440 --> 00:13:16.720
+into request scan
+
+00:13:16.720 --> 00:13:18.800
+it ends up calling nnmail.newmail and it
+
+00:13:18.800 --> 00:13:21.760
+says I am calling this as an nml server
+
+00:13:21.760 --> 00:13:23.279
+and here are some of my callback
+
+00:13:23.279 --> 00:13:24.959
+functions and my variables that I would
+
+00:13:24.959 --> 00:13:26.000
+like you to use
+
+00:13:26.000 --> 00:13:28.000
+when you are getting your email so in
+
+00:13:28.000 --> 00:13:30.120
+this way the code is sort of you know
+
+00:13:30.120 --> 00:13:33.120
+inter-interleaved between the the child
+
+00:13:33.120 --> 00:13:35.680
+class and the parent class even though
+
+00:13:35.680 --> 00:13:37.120
+we're not talking in terms of classes
+
+00:13:37.120 --> 00:13:39.440
+here at all really
+
+00:13:39.440 --> 00:13:42.160
+so that's how noose works right now I
+
+00:13:42.160 --> 00:13:42.959
+hope that's clear
+
+00:13:42.959 --> 00:13:45.519
+it certainly wasn't to me and I still
+
+00:13:45.519 --> 00:13:46.560
+have to go refresh my
+
+00:13:46.560 --> 00:13:48.079
+memory I'd like to talk a little bit
+
+00:13:48.079 --> 00:13:50.079
+about sort of the newer
+
+00:13:50.079 --> 00:13:51.600
+libraries that are available now for
+
+00:13:51.600 --> 00:13:54.240
+doing object-oriented code
+
+00:13:54.240 --> 00:13:56.959
+uh as I mentioned I think earlier nno
+
+00:13:56.959 --> 00:13:59.279
+the copyright headers for 1996 so that's
+
+00:13:59.279 --> 00:14:00.320
+pretty venerable
+
+00:14:00.320 --> 00:14:02.639
+coincidentally around the same time eric
+
+00:14:02.639 --> 00:14:05.519
+ludlum started developing e-I-e-I-o
+
+00:14:05.519 --> 00:14:08.320
+which is a which is sort of inspired by
+
+00:14:08.320 --> 00:14:09.360
+a common lisp's
+
+00:14:09.360 --> 00:14:12.720
+common lisp object system um I got a
+
+00:14:12.720 --> 00:14:14.240
+very good introduction to that from this
+
+00:14:14.240 --> 00:14:14.959
+book
+
+00:14:14.959 --> 00:14:16.399
+practical common lisp which I would
+
+00:14:16.399 --> 00:14:18.000
+encourage you to look at if you haven't
+
+00:14:18.000 --> 00:14:20.079
+which you probably have anyway
+
+00:14:20.079 --> 00:14:22.320
+e-I-e-I-o was incorporated into Emacs in
+
+00:14:22.320 --> 00:14:23.920
+2010
+
+00:14:23.920 --> 00:14:27.839
+so that yeah e-I-e-I-o provides um
+
+00:14:27.839 --> 00:14:30.240
+the deaf class statements it provides
+
+00:14:30.240 --> 00:14:32.079
+deaf generics deaf methods all that sort
+
+00:14:32.079 --> 00:14:32.639
+of stuff
+
+00:14:32.639 --> 00:14:34.800
+sort of a common lisp object-oriented
+
+00:14:34.800 --> 00:14:36.320
+code
+
+00:14:36.320 --> 00:14:38.399
+at some point stephan monier's money
+
+00:14:38.399 --> 00:14:39.760
+money another name I haven't pronounced
+
+00:14:39.760 --> 00:14:41.199
+it all out
+
+00:14:41.199 --> 00:14:43.839
+started either cleaning up that code or
+
+00:14:43.839 --> 00:14:45.120
+for one reason or another writing a
+
+00:14:45.120 --> 00:14:46.959
+re-implementation of generic functions
+
+00:14:46.959 --> 00:14:48.000
+which was added
+
+00:14:48.000 --> 00:14:51.440
+uh in 2015 and then throughout this time
+
+00:14:51.440 --> 00:14:51.920
+another
+
+00:14:51.920 --> 00:14:54.639
+sort of object-oriented style
+
+00:14:54.639 --> 00:14:55.760
+declaration is
+
+00:14:55.760 --> 00:14:58.160
+defstruct which started off in the cl
+
+00:14:58.160 --> 00:15:00.000
+libraries
+
+00:15:00.000 --> 00:15:01.600
+implemented with vectors later was
+
+00:15:01.600 --> 00:15:02.959
+implemented with records so they're
+
+00:15:02.959 --> 00:15:04.639
+easier to target
+
+00:15:04.639 --> 00:15:06.720
+anyway that's another option so how
+
+00:15:06.720 --> 00:15:08.399
+would we this is I'm probably out of
+
+00:15:08.399 --> 00:15:09.279
+time already but
+
+00:15:09.279 --> 00:15:13.839
+we're only getting to the part
+
+00:15:13.839 --> 00:15:15.760
+the whole point of this is how would we
+
+00:15:15.760 --> 00:15:17.920
+rewrite someone news's code to use these
+
+00:15:17.920 --> 00:15:19.920
+newer libraries
+
+00:15:19.920 --> 00:15:21.760
+if we didn't have to support third party
+
+00:15:21.760 --> 00:15:23.839
+libraries this wouldn't be that hard
+
+00:15:23.839 --> 00:15:26.639
+but out there noose is really up on uh
+
+00:15:26.639 --> 00:15:28.160
+you know backwards compatibility and not
+
+00:15:28.160 --> 00:15:30.240
+breaking people's stuff and you know
+
+00:15:30.240 --> 00:15:33.040
+multi-decade support for things so there
+
+00:15:33.040 --> 00:15:34.240
+are people out there who have written
+
+00:15:34.240 --> 00:15:35.759
+third-party libraries
+
+00:15:35.759 --> 00:15:38.480
+um defining new backends for you can use
+
+00:15:38.480 --> 00:15:40.000
+like hacker news or whatever as
+
+00:15:40.000 --> 00:15:41.759
+a as a server so we want to be able to
+
+00:15:41.759 --> 00:15:43.199
+support those if you didn't have to
+
+00:15:43.199 --> 00:15:44.240
+support those it'd be fine you'd
+
+00:15:44.240 --> 00:15:46.079
+re-implement you'd use generic functions
+
+00:15:46.079 --> 00:15:47.440
+you'd use either structure classes
+
+00:15:47.440 --> 00:15:48.560
+whatever but we got a
+
+00:15:48.560 --> 00:15:51.040
+it's a little bit tricky to support
+
+00:15:51.040 --> 00:15:52.000
+these other people's
+
+00:15:52.000 --> 00:15:54.320
+libraries so one of the things we can do
+
+00:15:54.320 --> 00:15:56.079
+is rewrite the defu
+
+00:15:56.079 --> 00:15:59.279
+so if you remember defu is the thing
+
+00:15:59.279 --> 00:16:00.079
+that uh
+
+00:16:00.079 --> 00:16:03.120
+or sorry uh defu
+
+00:16:03.120 --> 00:16:04.800
+is the thing that defines methods that
+
+00:16:04.800 --> 00:16:07.040
+operate on object answers
+
+00:16:07.040 --> 00:16:10.160
+instances and we can uh rewrite that to
+
+00:16:10.160 --> 00:16:10.639
+use
+
+00:16:10.639 --> 00:16:13.440
+cldef generic and that's this is fairly
+
+00:16:13.440 --> 00:16:14.240
+fairly simple
+
+00:16:14.240 --> 00:16:15.440
+it looks like a lot of code it's not a
+
+00:16:15.440 --> 00:16:17.759
+lot of good for instance we have the
+
+00:16:17.759 --> 00:16:20.320
+new closed server code that we looked at
+
+00:16:20.320 --> 00:16:21.199
+earlier
+
+00:16:21.199 --> 00:16:22.720
+and we have this phone call and the new
+
+00:16:22.720 --> 00:16:24.560
+skip function so this would look
+
+00:16:24.560 --> 00:16:28.720
+like using generic functions and methods
+
+00:16:28.720 --> 00:16:30.240
+it would look like this we'd have
+
+00:16:30.240 --> 00:16:32.959
+a generic def generic which is just a
+
+00:16:32.959 --> 00:16:34.560
+sort of a declaration
+
+00:16:34.560 --> 00:16:36.320
+and a doc string and then we have those
+
+00:16:36.320 --> 00:16:37.680
+implementations
+
+00:16:37.680 --> 00:16:40.320
+so we can see what the original code
+
+00:16:40.320 --> 00:16:42.399
+does here is it first says okay what
+
+00:16:42.399 --> 00:16:44.720
+type is our our is our argument here and
+
+00:16:44.720 --> 00:16:45.839
+if it's a string
+
+00:16:45.839 --> 00:16:48.560
+then go and get the proper s the proper
+
+00:16:48.560 --> 00:16:50.160
+method definition
+
+00:16:50.160 --> 00:16:52.480
+from that string so the way we do that
+
+00:16:52.480 --> 00:16:53.920
+with methods is we
+
+00:16:53.920 --> 00:16:56.000
+we say if the server is a string so if
+
+00:16:56.000 --> 00:16:57.440
+it matches this type
+
+00:16:57.440 --> 00:16:58.720
+then what we're going to do is just
+
+00:16:58.720 --> 00:17:00.320
+recall we're going to call this function
+
+00:17:00.320 --> 00:17:02.160
+all over again
+
+00:17:02.160 --> 00:17:05.199
+using uh basically the same code here
+
+00:17:05.199 --> 00:17:06.400
+the same code that takes a string and
+
+00:17:06.400 --> 00:17:07.600
+gets the object so
+
+00:17:07.600 --> 00:17:10.640
+this does this can add extra function
+
+00:17:10.640 --> 00:17:11.600
+calls
+
+00:17:11.600 --> 00:17:12.880
+depending on how you've written the rest
+
+00:17:12.880 --> 00:17:14.880
+of your code um but this is sort of the
+
+00:17:14.880 --> 00:17:16.640
+canonical way of doing this
+
+00:17:16.640 --> 00:17:19.679
+uh using methods then our next part here
+
+00:17:19.679 --> 00:17:20.559
+is
+
+00:17:20.559 --> 00:17:22.000
+nishkit function we're going to get a
+
+00:17:22.000 --> 00:17:24.559
+function called closed server
+
+00:17:24.559 --> 00:17:26.079
+the difference here is that all these
+
+00:17:26.079 --> 00:17:27.360
+functions are all going to be called
+
+00:17:27.360 --> 00:17:28.000
+close
+
+00:17:28.000 --> 00:17:29.360
+news close server they're not going to
+
+00:17:29.360 --> 00:17:31.120
+be called news like nni my
+
+00:17:31.120 --> 00:17:32.799
+closed server and ntp close server
+
+00:17:32.799 --> 00:17:34.400
+they're all going to have the same name
+
+00:17:34.400 --> 00:17:36.160
+and what we do is uh we have an around
+
+00:17:36.160 --> 00:17:37.440
+method
+
+00:17:37.440 --> 00:17:40.640
+for any server that is a const which is
+
+00:17:40.640 --> 00:17:43.679
+which is as close as we care to get uh
+
+00:17:43.679 --> 00:17:45.520
+for you know zeroing in on the type that
+
+00:17:45.520 --> 00:17:46.799
+we're looking for
+
+00:17:46.799 --> 00:17:48.559
+we put in a round method on that so that
+
+00:17:48.559 --> 00:17:50.480
+we can call the next method which we'll
+
+00:17:50.480 --> 00:17:51.679
+call the more specific
+
+00:17:51.679 --> 00:17:53.440
+method and then we have our other
+
+00:17:53.440 --> 00:17:55.600
+bookkeeping code to clean up you know
+
+00:17:55.600 --> 00:17:57.280
+set up tear down code we'll go around
+
+00:17:57.280 --> 00:17:58.640
+that
+
+00:17:58.640 --> 00:18:00.080
+and then in one of the back-end
+
+00:18:00.080 --> 00:18:02.080
+definitions for instance in an imap
+
+00:18:02.080 --> 00:18:04.320
+we have another news closed server thing
+
+00:18:04.320 --> 00:18:05.760
+this looks at the server
+
+00:18:05.760 --> 00:18:08.880
+and it says is this server a list that
+
+00:18:08.880 --> 00:18:10.799
+starts with a symbol and an imap and if
+
+00:18:10.799 --> 00:18:12.480
+it is then we're almost guaranteed that
+
+00:18:12.480 --> 00:18:13.679
+this is what we wanted
+
+00:18:13.679 --> 00:18:15.840
+and then this is where we would insert
+
+00:18:15.840 --> 00:18:17.600
+all the rest of the code from anonymous
+
+00:18:17.600 --> 00:18:18.960
+closed server
+
+00:18:18.960 --> 00:18:20.799
+where we'd re-redefine that to look like
+
+00:18:20.799 --> 00:18:22.880
+this so it's not that hard
+
+00:18:22.880 --> 00:18:26.080
+theoretically so what we would do
+
+00:18:26.080 --> 00:18:28.720
+is take the defu macro macro and then
+
+00:18:28.720 --> 00:18:29.679
+rewrite that
+
+00:18:29.679 --> 00:18:32.240
+so that it actually defines a cl def
+
+00:18:32.240 --> 00:18:33.039
+method like
+
+00:18:33.039 --> 00:18:35.520
+one of these now there's a couple of
+
+00:18:35.520 --> 00:18:36.320
+these things
+
+00:18:36.320 --> 00:18:38.960
+unfortunately it's not that easy get rid
+
+00:18:38.960 --> 00:18:41.200
+of you
+
+00:18:41.200 --> 00:18:43.490
+a couple of these things
+
+00:18:43.490 --> 00:18:46.400
+[Music]
+
+00:18:46.400 --> 00:18:49.039
+that don't use their server as the first
+
+00:18:49.039 --> 00:18:49.919
+argument
+
+00:18:49.919 --> 00:18:52.400
+or any of the arguments or it's an
+
+00:18:52.400 --> 00:18:53.280
+optional argument
+
+00:18:53.280 --> 00:18:54.720
+and we need the server to be in there to
+
+00:18:54.720 --> 00:18:56.640
+dispatch on its type
+
+00:18:56.640 --> 00:18:58.799
+if the server doesn't show up as a as a
+
+00:18:58.799 --> 00:19:00.080
+required
+
+00:19:00.080 --> 00:19:01.760
+argument we're not going to be able to
+
+00:19:01.760 --> 00:19:03.600
+locate the the proper
+
+00:19:03.600 --> 00:19:07.440
+function call so in the case of
+
+00:19:07.440 --> 00:19:10.640
+noose request group here we start with
+
+00:19:10.640 --> 00:19:12.080
+the group it's the group that matters
+
+00:19:12.080 --> 00:19:12.720
+and we get
+
+00:19:12.720 --> 00:19:14.960
+the newscommand method as an optional
+
+00:19:14.960 --> 00:19:16.240
+argument
+
+00:19:16.240 --> 00:19:18.559
+so that's not cool we don't want that so
+
+00:19:18.559 --> 00:19:20.480
+what we need instead is something that
+
+00:19:20.480 --> 00:19:21.360
+looks like this
+
+00:19:21.360 --> 00:19:23.840
+what we're going to do with uh this is
+
+00:19:23.840 --> 00:19:25.360
+gonna be just terrible terrible code but
+
+00:19:25.360 --> 00:19:26.640
+hopefully it won't get used very often
+
+00:19:26.640 --> 00:19:28.160
+it's gonna be really embarrassing
+
+00:19:28.160 --> 00:19:30.559
+um defu what's what definitely was gonna
+
+00:19:30.559 --> 00:19:31.520
+have to do is
+
+00:19:31.520 --> 00:19:33.200
+say okay is this a function that doesn't
+
+00:19:33.200 --> 00:19:34.559
+have the server as the first argument
+
+00:19:34.559 --> 00:19:35.360
+and if it does
+
+00:19:35.360 --> 00:19:36.960
+it's gonna say oh it's news request
+
+00:19:36.960 --> 00:19:38.400
+group what happens has to happen with
+
+00:19:38.400 --> 00:19:39.280
+news request group
+
+00:19:39.280 --> 00:19:40.799
+is we take the news command method and
+
+00:19:40.799 --> 00:19:43.200
+we're going to move it up to the front
+
+00:19:43.200 --> 00:19:46.240
+to the first argument here and it's
+
+00:19:46.240 --> 00:19:47.520
+either going to be
+
+00:19:47.520 --> 00:19:48.720
+it's either going to be given or it's
+
+00:19:48.720 --> 00:19:50.840
+going to be nil because it's it is
+
+00:19:50.840 --> 00:19:52.080
+optional
+
+00:19:52.080 --> 00:19:54.320
+okay I briefly edited the space time
+
+00:19:54.320 --> 00:19:55.760
+continuum there to conceal the fact that
+
+00:19:55.760 --> 00:19:56.400
+I had
+
+00:19:56.400 --> 00:19:57.679
+actually not finished writing the code
+
+00:19:57.679 --> 00:19:59.440
+that I was supposed to write anyway
+
+00:19:59.440 --> 00:20:02.159
+um so now we have once we've reordered
+
+00:20:02.159 --> 00:20:02.960
+the
+
+00:20:02.960 --> 00:20:04.320
+the arguments to the function then we
+
+00:20:04.320 --> 00:20:05.760
+have to check our various possible
+
+00:20:05.760 --> 00:20:06.880
+values one is
+
+00:20:06.880 --> 00:20:08.640
+uh that the server was not passed in in
+
+00:20:08.640 --> 00:20:10.080
+which case we recall
+
+00:20:10.080 --> 00:20:12.400
+request group with the server um the
+
+00:20:12.400 --> 00:20:13.840
+other is that it's just a string in
+
+00:20:13.840 --> 00:20:15.360
+which case we do that and then this is
+
+00:20:15.360 --> 00:20:16.559
+sort of the the normal
+
+00:20:16.559 --> 00:20:18.559
+the normal case that we would expect to
+
+00:20:18.559 --> 00:20:20.720
+cons so that's not that bad it's not you
+
+00:20:20.720 --> 00:20:21.039
+know
+
+00:20:21.039 --> 00:20:23.760
+it's not beautiful um I would be sort of
+
+00:20:23.760 --> 00:20:24.480
+ashamed to
+
+00:20:24.480 --> 00:20:26.159
+let anybody see that particular macro
+
+00:20:26.159 --> 00:20:28.000
+but I think that it would work okay
+
+00:20:28.000 --> 00:20:30.640
+now the more difficult thing is going to
+
+00:20:30.640 --> 00:20:31.440
+be
+
+00:20:31.440 --> 00:20:34.640
+the data variables so
+
+00:20:34.640 --> 00:20:37.600
+the equivalent of def vu because our two
+
+00:20:37.600 --> 00:20:39.360
+options for defining classes here are
+
+00:20:39.360 --> 00:20:41.039
+def struct and def class both of which
+
+00:20:41.039 --> 00:20:41.919
+required you
+
+00:20:41.919 --> 00:20:45.280
+to define the slots inside this macro
+
+00:20:45.280 --> 00:20:46.960
+itself
+
+00:20:46.960 --> 00:20:49.039
+so defu is top level um how do we get
+
+00:20:49.039 --> 00:20:51.280
+the top level this top level macro
+
+00:20:51.280 --> 00:20:55.039
+uh to insert slot names into these
+
+00:20:55.039 --> 00:20:56.240
+definitions it's
+
+00:20:56.240 --> 00:20:58.960
+it's possible that it'll be um that I
+
+00:20:58.960 --> 00:21:00.240
+could monkey patch
+
+00:21:00.240 --> 00:21:03.039
+uh an existing struct or an existing
+
+00:21:03.039 --> 00:21:04.799
+class to add a new slot into it that
+
+00:21:04.799 --> 00:21:05.280
+sounds
+
+00:21:05.280 --> 00:21:07.760
+ugly the other option would be to give
+
+00:21:07.760 --> 00:21:09.600
+it a server variable slot which is just
+
+00:21:09.600 --> 00:21:11.520
+a generalized bucket
+
+00:21:11.520 --> 00:21:13.760
+that holds anything that gets defined
+
+00:21:13.760 --> 00:21:15.520
+via def loop
+
+00:21:15.520 --> 00:21:16.720
+I don't like either of those solutions
+
+00:21:16.720 --> 00:21:18.799
+but I'm I don't see any other
+
+00:21:18.799 --> 00:21:22.480
+any other way of doing that so we re
+
+00:21:22.480 --> 00:21:25.520
+rewrite the nno declare macro to either
+
+00:21:25.520 --> 00:21:27.440
+be a destructor or a def class
+
+00:21:27.440 --> 00:21:29.840
+and we rewrite the def boom macro to
+
+00:21:29.840 --> 00:21:31.039
+somehow
+
+00:21:31.039 --> 00:21:33.039
+associate that variable name the symbol
+
+00:21:33.039 --> 00:21:34.480
+with the with the resulting class
+
+00:21:34.480 --> 00:21:36.159
+definition
+
+00:21:36.159 --> 00:21:37.760
+then the last question is do we use
+
+00:21:37.760 --> 00:21:39.600
+structure classes
+
+00:21:39.600 --> 00:21:41.600
+they both got their their strengths and
+
+00:21:41.600 --> 00:21:43.200
+their weaknesses
+
+00:21:43.200 --> 00:21:46.480
+the nice thing is that I mean I've got
+
+00:21:46.480 --> 00:21:47.520
+how many servers you're going to have
+
+00:21:47.520 --> 00:21:49.600
+really I've got I think less than 10
+
+00:21:49.600 --> 00:21:51.919
+uh truly deranged mine might have as as
+
+00:21:51.919 --> 00:21:52.960
+many as
+
+00:21:52.960 --> 00:21:55.440
+50 let's double that to 100 100 of
+
+00:21:55.440 --> 00:21:56.480
+anything is not going to matter it
+
+00:21:56.480 --> 00:21:58.400
+doesn't matter what we use
+
+00:21:58.400 --> 00:22:00.159
+death structures are simpler they're
+
+00:22:00.159 --> 00:22:02.720
+lighter weight they're defined on top of
+
+00:22:02.720 --> 00:22:05.600
+the direct the c records so you know
+
+00:22:05.600 --> 00:22:06.960
+that's nice
+
+00:22:06.960 --> 00:22:08.559
+the slots don't carry very much
+
+00:22:08.559 --> 00:22:10.320
+information with them there's no type
+
+00:22:10.320 --> 00:22:11.760
+information there's no doc string for
+
+00:22:11.760 --> 00:22:14.480
+the slots themselves
+
+00:22:14.480 --> 00:22:16.559
+they can also only do single inheritance
+
+00:22:16.559 --> 00:22:17.919
+which some might say
+
+00:22:17.919 --> 00:22:21.120
+was an advantage def class each slot
+
+00:22:21.120 --> 00:22:22.640
+gets a lot more information associated
+
+00:22:22.640 --> 00:22:24.000
+with it with it which I think can be
+
+00:22:24.000 --> 00:22:24.480
+nice
+
+00:22:24.480 --> 00:22:27.120
+it can do multiple inheritance if you're
+
+00:22:27.120 --> 00:22:28.799
+going to go there
+
+00:22:28.799 --> 00:22:30.720
+they are heavier weight in particular
+
+00:22:30.720 --> 00:22:32.640
+their printed representation is gross
+
+00:22:32.640 --> 00:22:34.080
+it's enormous
+
+00:22:34.080 --> 00:22:35.840
+so if you see one show up in a back
+
+00:22:35.840 --> 00:22:37.520
+trace or in your messages buffer can
+
+00:22:37.520 --> 00:22:38.240
+really
+
+00:22:38.240 --> 00:22:39.520
+it can really blow that up and make it
+
+00:22:39.520 --> 00:22:41.360
+hard to read this of course won't be an
+
+00:22:41.360 --> 00:22:43.200
+issue because our code won't have any
+
+00:22:43.200 --> 00:22:46.240
+errors in it um my argument for multiple
+
+00:22:46.240 --> 00:22:48.320
+inheritance here is that I can imagine
+
+00:22:48.320 --> 00:22:51.280
+new servers falling into sort of like a
+
+00:22:51.280 --> 00:22:52.720
+little two by two matrix of
+
+00:22:52.720 --> 00:22:56.240
+of parent classes one being news versus
+
+00:22:56.240 --> 00:22:56.799
+mail
+
+00:22:56.799 --> 00:23:00.320
+so news the messages belong to somebody
+
+00:23:00.320 --> 00:23:00.720
+else
+
+00:23:00.720 --> 00:23:02.080
+you can't touch them you can't delete
+
+00:23:02.080 --> 00:23:03.840
+them mail meaning
+
+00:23:03.840 --> 00:23:06.000
+the messages are under your command
+
+00:23:06.000 --> 00:23:08.960
+either a local mail dealer a remote imap
+
+00:23:08.960 --> 00:23:11.039
+you're allowed to spool them copy them
+
+00:23:11.039 --> 00:23:12.640
+delete them at will
+
+00:23:12.640 --> 00:23:13.919
+and then the other sort of line of the
+
+00:23:13.919 --> 00:23:16.400
+matrix would be a local file system
+
+00:23:16.400 --> 00:23:19.760
+versus some kind of a you know server
+
+00:23:19.760 --> 00:23:20.559
+port
+
+00:23:20.559 --> 00:23:23.280
+remote access and that second the server
+
+00:23:23.280 --> 00:23:24.960
+port remote access thing might require
+
+00:23:24.960 --> 00:23:26.880
+authentication it might require a keep
+
+00:23:26.880 --> 00:23:28.559
+alive for a connection
+
+00:23:28.559 --> 00:23:30.159
+um it's there's going to be a process
+
+00:23:30.159 --> 00:23:31.600
+there rather than just file system
+
+00:23:31.600 --> 00:23:32.400
+commands
+
+00:23:32.400 --> 00:23:33.840
+so I could see if I was going to do
+
+00:23:33.840 --> 00:23:35.360
+multiple inheritance that's what I would
+
+00:23:35.360 --> 00:23:36.240
+do those two
+
+00:23:36.240 --> 00:23:39.039
+those two possible parent classes anyway
+
+00:23:39.039 --> 00:23:40.400
+that's as far as I've gotten
+
+00:23:40.400 --> 00:23:41.520
+I thought that I would be able to write
+
+00:23:41.520 --> 00:23:43.279
+more of this code before I did this talk
+
+00:23:43.279 --> 00:23:44.720
+but instead I spent the whole time
+
+00:23:44.720 --> 00:23:46.720
+messing with video codecs but that's
+
+00:23:46.720 --> 00:23:48.320
+where we're at and I'm going to cut
+
+00:23:48.320 --> 00:23:49.440
+myself off now
+
+00:23:49.440 --> 00:23:50.960
+I hope there are questions I hope I'm
+
+00:23:50.960 --> 00:23:53.440
+there to to answer your questions
+
+00:23:53.440 --> 00:23:55.919
+and thanks very much again to everyone
+
+00:23:55.919 --> 00:23:57.120
+involved
+
+00:23:57.120 --> 00:23:59.279
+bye