Why eev has a weird elisp tutorial and how to use it (subtitles)
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00:00 Hi! My name is Eduardo Ochs, I'm the author
00:03 of an Emacs package called eev,
00:05 and the title of this video is: "Why eev
00:09 comes with a weird elisp tutorial and
00:11 how to use it".
00:13 Before starting let me just explain what
00:15 is this image here.
00:18 It's a frame from my most
00:21 favorite animation movie ever. Its title
00:24 in English is "Gwen, or the book of sand"
00:27 and it's available on youtube; you can
00:30 watch it there.
00:33 One of my missions on Earth is to
00:35 convince more people to watch that
00:37 movie.
00:38 I've watched it more than 30 times. I've
00:41 shown it to many people, and every
00:43 time that I watch it it blows my mind in
00:45 different ways.
00:47 Anyway, let me go back.
00:50 One more thing before starting...
00:53 Emacs comes with an Emacs Lisp
00:55 tutorial that is very famous -
00:59 it's called "An Introduction to
01:00 Programming in Emacs Lisp".
01:03 It comes as an info manual, and it's
01:06 actually a book.
01:09 Using info mode you can navigate
01:11 through it - through its chapter, sections,
01:14 and so on.
01:15 If you're a beginner you're probably
01:17 going to use these, uh,
01:20 things here in the toolbar; if you're not
01:22 a beginner you can use,
01:25 for example, the
01:27 square brackets to navigate to the
01:29 previous and the next section in a
01:31 certain order.
01:33 Let me use that now to show how big this
01:35 manual is.
01:39 These are all its sections and
01:41 subsections and so on,
01:44 and it's huge -
01:46 very huge -
01:47 oh no, it never ends -
01:52 That's it. So: a zillion of sections.
02:02 Eev comes with a very short tutorial
02:07 on Emacs Lisp that you can
02:09 access by just typing M-7 M-j.
02:13 Here - let's see its size. Let me
02:18 turn on the scroll bar here...
02:20 if we scroll here, and go
02:23 to the end of the tutorial - it's here
02:27 it has just a bit more than 600 lines.
02:34 I say here that "This is a very quick
02:38 introduction to Emacs Lisp.
02:41 My intent here is not to teach people
02:43 how to _write_ Elisp code, only to teach
02:45 them to _read_ Elisp code." I consider that
02:48 reading and writing are two different
02:49 stages, and in the beginning people are
02:52 mostly going to want to read things...
02:55 like to understand what the
02:57 source code means, or
03:00 to understand how a certain template is
03:03 prepared, and so on...
03:06 And I say here that `Different people
03:08 prefer different kinds of tutorials'
03:11 and many people - actually most people -
03:14 love the the introduction to Emacs Lisp -
03:15 this one here - but i don't -
03:23 and in this video i'm going to explain why.
03:26 This tutorial here - this short one - is what
03:29 I would have liked to have had access to
03:31 when I started learning Emacs Lisp.
03:37 Let me go back a second.
03:42 I started to write to this tutorial
03:44 because I was invited to teach a minicourse
03:47 on LaTeX to
03:49 students that had never used Emacs
03:52 before, and I said:
03:54 `Oh, okay, I'm going to teach it, but
03:56 everybody is going to be forced to use
04:01 Emacs and eev - but I'm going to do it in a
04:04 certain way in which it's not going to be
04:05 very painful'.
04:07 And so, I used eev to make people learn Emacs
04:11 in a certain way,
04:13 and every time that a person
04:16 had a curiosity about something in Lisp
04:18 and wanted to understand the syntax
04:22 or the defuns, or backquotes,
04:25 or whatever, I said `oh, look at the
04:30 sections such and such
04:32 in my Elisp tutorial'.
04:38 So these people knew very few
04:41 keys of Emacs in the beginning
04:43 they basically knew the three most basic
04:46 keys, that are M-e, M-k, and M-j...
04:50 M-e executes the
04:52 sexp in the current line,
04:56 M-k can be used to to kill the current
04:59 buffer, which usually means to go back,
05:03 and M-j jumps to several different places...
05:08 and if you run M-j without a numerical
05:10 argument it shows this temporary buffer here
05:14 that... here it shows some of the main
05:18 targets - that have numbers assigned to them
05:24 and here you can see the other targets.
05:27 So this line here means that
05:31 if you type M-j with the numeric prefix 7
05:36 it is going to execute this thing here,
05:39 that goes to the Elisp tutorial...
05:43 and these are the the things that are
05:45 most basic that beginners learn first.
05:51 These things here - this one here, M-5 M-j,
05:56 is the basic tutorial, called
06:00 (find-eev-quick-intro),
06:04 this one, M-2 M-j, is a fake tutorial
06:07 that is mostly an index of keys,
06:12 and this one here - M-1 M-j -
06:15 opens a buffer with our notes...
06:20 I always say to the beginners
06:23 that in the beginning they should put all
06:27 their notes in this buffer here - ~/TODO -
06:33 and that they shouldn't mind if their
06:35 notes are messy - they can clean
06:37 them up later -
06:41 and this thing here also shows some keys
06:44 for opening the file with the notes in
06:47 the window at the right from any place...
06:53 so, for example if we are in the
06:55 elisp tutorial, here, and we find
06:59 something interesting, say, on
07:02 section 3 - for example this block here -
07:08 we can run this thing here, show our
07:12 buffer with notes at the window at the
07:15 right, and we can copy the thing here to
07:17 our notes.
07:23 Just one comment before showing other things...
07:29 M-7 M-j goes to the elisp tutorial,
07:34 and the last line of this header
07:36 says that you can open this tutorial
07:42 or recreate it with M-7 M-j...
07:46 It is a sandbox, in the sense that you
07:48 can make any mess here
07:52 and then recreate it.
07:59 Some other tutorials have numbers,
08:02 like this. For example, this is the
08:04 fake tutorial that is just an index,
08:07 and it says that you can access this
08:09 thing with M-5 M-0 M-j...
08:13 and these other ones I have already shown.
08:23 One important thing is that people can
08:28 create links to the sections of the...
08:31 of my elisp tutorial very easily.
08:35 For example, suppose that you're one of
08:42 the students in my workshop, you are
08:44 starting to learn Emacs today,
08:47 and you learned the basic ideas of how
08:50 to create elisp hyperlinks, and you
08:56 think that there's something interesting
08:58 in this section here - section 5.
09:02 So you can create a link to it by hand.
09:04 For example you can simply type this
09:09 (find-elisp-intro ...)
09:14 initially by hand; later you can learn
09:17 the tricks for generating
09:19 this automatically -
09:22 and you can copy the title
09:25 to this position here.
09:27 Now you have something that you if
09:29 execute... if you execute this you
09:32 go exactly to this section here.
09:43 But let me go back...
09:49 Let me now explain some
09:52 differences in style between the
09:54 standard tutorial and my tutorial.
10:01 I think that the first thing that made
10:03 me dislike the Emacs Lisp Intro
10:06 is that it is "An introduction to
10:10 programming in Emacs Lisp
10:13 _for people who are not programmers_",
10:16 and I was trying very hard to become a
10:18 programmer, i was really thinking like a
10:20 programmer, and I was taking notes and
10:23 creating exercises and so on...
10:25 and so this thing felt
10:27 more like a book that
10:30 should be read like a book, not like
10:32 code that you can execute by
10:35 just typing M-e.
10:39 It felt non-Emacs-y.
10:44 I also said that this is huge... this is
10:48 the menu with the chapters and sections
10:51 and subsections and so on...
10:56 in some situations it has
11:01 faces here - in the sense of different
11:03 fonts -
11:04 and sometimes it's not totally clear if
11:07 this difference is important or not, and
11:13 if we copy a part of this to our notes
11:18 and we save our notes
11:20 then the faces are going to disappear -
11:22 the the thing is going to become plain
11:24 text without the
11:26 the different fonts.
11:32 Also, the manual is full of
11:37 examples like this, that are not complete
11:39 chunks of code, they are just
11:45 excerpts from bigger functions.
11:55 So, in short: it is big,
11:58 it is hard to navigate because it has
12:01 zillion of sections, it uses faces, it is
12:04 read-only -
12:06 remember that in my tutorial you can
12:11 duplicate a line, for example, and check
12:14 what happens if you change
12:18 one item of a list by something else -
12:21 for example what happens
12:23 if you change this by 40 or by a string,
12:26 and you can execute these things here...
12:29 so this is a sandbox where you can execute
12:31 things, and this does not happen
12:34 in the Emacs Lisp Intro.
12:40 Also, the Emacs Lisp Intro has just a
12:43 few executable examples per page,
12:46 while my tutorial has many -
12:49 for example here: all these things
12:51 are different examples...
12:57 and one thing that really bothered me is
13:02 that I prefer to believe that Emacs
13:08 was made in two levels: first people took
13:12 a Lisp interpreter -
13:14 no, sorry, three levels - people first took
13:17 at Lisp interpreter, and then they
13:22 programmed in it a handful
13:23 of functions for dealing with keys,
13:28 buffers, files, windows and so on; just a
13:31 few basic things...
13:32 and at one point they had a very basic
13:35 editor that had Lisp inside,
13:37 and they they could change its Lisp code
13:40 interactively using the editor itself...
13:44 and then they started to build
13:47 an editor that was much more powerful,
13:50 and also to extend the Lisp with
13:53 more advanced features...
13:56 but I prefer to think that that we have
13:58 this division, with basic Lisp on the
14:01 bottom, and then basic editing functions
14:02 on top, and then
14:07 a huge structure with zillions of
14:10 editing functions -
14:12 and the Emacs Lisp tutorial does not make
14:15 this distinction very clearly
14:18 and it explains basic Lisp at the
14:21 same time as the
14:22 as editing functions, because
14:25 it wants to explain
14:27 how how people can write useful
14:29 functions, and useful functions are
14:31 usually
14:32 functions that edit things.
14:36 Another thing that I really didn't like
14:39 in it is that it has
14:42 very few links to the primary sources.
14:45 Here we are inside Emacs, and it's
14:48 very easy to access
14:53 each one of the manuals
14:54 and the source code.
14:57 For example, here
15:01 I have a section of my tutorial that
15:03 ends with this block here: it says
15:07 "for more info on the other types of
15:10 list objects..." - oops, it's Lisp
15:13 objects, sorry there's a typo here -
15:16 "see blah blah" and each of these things
15:18 is a link to the Emacs Lisp manual.
15:25 Also, here we have links to the Wikipedia,
15:29 and in other places with we have links
15:31 to the Emacs manual...
15:36 and I think that in a couple of places
15:38 we have links to the source code too -
15:44 and the Emacs Lisp Intro does not
15:47 do that.
15:48 It is made to be
15:51 the online version of a book, and I
15:55 think that this is a bit frustrating.
15:58 And the main point - and this is something
16:01 that very people have noticed -
16:03 is that my tutorial works in two ways.
16:09 It has some contents here, so people can
16:12 _read_ it
16:13 but it also has lots of design choices
16:17 and stylistical choices - I decided to
16:20 present things in a certain way...
16:24 and when people
16:28 run these examples
16:30 they're probably going to
16:32 become familiar with these
16:35 stylistical choices, and
16:37 when they start to take their own notes
16:40 they are probably going to use
16:42 some of these ideas on their notes.
16:44 So they are going to do something like
16:48 this, in which they put
16:50 several similar examples close to
16:54 one another, starting by the most basic
16:56 ones.
16:57 They can also put just a bit of text
17:02 instead of having to explain lots of
17:04 things, and they are also -
17:08 I hope -
17:09 they will also
17:11 try to use this style here,
17:14 in which we put important links
17:17 to everything that that we find, so
17:21 instead of trying to reproduce the
17:23 explanations
17:24 with our own words
17:27 we just put the links to
17:29 the sources where we can find the
17:32 full explanations.
17:35 The idea is that when people
17:38 are learning some
17:41 more advanced things that are not in the
17:43 manual they can
17:46 write their notes in this format
17:49 and they can even share these notes with
17:51 other people -
17:53 and in my workshops I often have
17:58 some moments in which people share their
18:00 notes, and of course people would
18:05 want to write notes that are
18:07 useful to other people, and notes that
18:10 are easy to change, and easy to
18:12 collaborate on -
18:14 and so one of the intentions of my
18:16 tutorials was to suggest a certain style
18:20 and convince people that they could
18:23 write their notes in this style.
18:27 This tutorial is very incomplete - it just
18:30 teaches the basic ideas -
18:32 but it also has a link here at the end
18:36 to another tutorial,
18:39 that is a tutorial on
18:43 lexical binding...
18:49 and it's very extensible.
18:52 And, by the way -
18:56 in several places in the source code of
18:58 eev I have examples that follow exactly
19:02 these same conventions, but they
19:03 appear in comments.
19:06 So people can also execute these
19:08 examples in comments
19:10 to understand ideas step by by step,
19:14 starting from the
19:16 most basic cases and then building more
19:19 complex functions on top of that.
19:24 Let me see...
19:29 so, yeah, that's what I wanted to
19:31 present. My tutorial is
19:33 much more "do-it-yourself-ish"
19:36 than the Emacs Lisp Intro...
19:46 And I confess that I always find the
19:48 reactions to my tutorial
19:52 quite puzzling, because I think that my
19:54 tutorial is very nice -
19:56 but sometimes I participate in
19:59 discussions in the Emacs mailing
20:01 lists and someone asks: "how
20:04 how do i do this? How can i learn" - for
20:07 example - "how to use back quote?"
20:09 and people say: there's blah blah blah,
20:11 there's this link to the manual, this link to
20:13 the other manual, and so on... and I recommend
20:15 trying the examples in my tutorial -
20:18 "you just need to learn the keys
20:21 such and such" -
20:23 and go to the section - let me see -
20:28 Backquote, section 10
20:32 and I never get any answers... I have the
20:35 impression that people
20:37 think that my tutorial is
20:40 far too weird, it's
20:42 like the product of a totally alien
20:45 mind, and no one uses it,
20:47 no one comments on it, and
20:50 then it's always...
20:53 I don't know, something
20:55 that just has to be ignored when I
20:57 mention it -
20:58 and I want to fix this.
21:00 And this video is - hopefully -
21:04 a first step
21:05 to make my tutorial less mysterious.
21:08 So: that's it. That's what I wanted to
21:11 show. Bye! =)