WEBVTT

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<i>36C3 preroll music</i>

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Herald: Welcome back to the WikipakaWG,

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live from Congress, wir haben Lucas da,
Lucas is back, Lucas was just here 15

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minutes ago, and now he's going to talk
about LilyPond. LilyPond is like LaTeX but

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for music notes and I hope you will have
fun!

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Lucas: Yeah. Thank you. Yeah, so I just
want to talk a bit about LilyPond, which

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is a really cool program, in my opinion,
to turn basically plain text input, such

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as the code you can see up here, into
beautifully typeset musical scores, such

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as down here, and that's actually the
result of this code up here, so you can

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try to find what belongs to what or
something. And, yeah, it’s free software

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obviously, it takes plain text as input,
which means you can put the code in a git

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repository and add comments and stuff,
it's all very nice, the output is PDF, or

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MIDI if you want to listen back to it, or
you can even integrate it into LaTeX or

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Texinfo documents, such as these slides,
which are created with LaTeX beamer and

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LilyPond in them, which is really funny
combination and it works perfectly well.

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So let's just start with some of the
syntax elements in a LilyPond file, and

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it's pretty straightforward to make a note
with a certain note name, you write that

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note name, so this is (I think) the
American note names, I'm not sure if the

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English ones use different ones, but
ABCDEFGA are the note names, and you write

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the letter and you get a note in return,
and the relative mode here means that each

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note is going to be as close as possible
to the previous one, for example this A

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here at the beginning and the one at the
end, that's the same input, but you can

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see they resulted in different notes, so
this is one octave higher than the

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original one, because that's the note
that's closest to the preceding note, and

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to control the duration of a note, you put
a number after it, for example this is a

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quarter note, so you put a number four
after it, this is a sixteenth note, so you

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put a sixteen after it, and if it's a
dotted note, such like this one, you put a

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literal dot after it. So there's a fair
bit of ASCII art in there, which is kind

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of cute, and if it's more complicated,
like the triplets here at the end, you

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write something like this \tuplet, so
that's kind of inspired by LaTeX syntax,

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this backslashes and braces business, so
this started out, actually, as a – I

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assume horrible – hack to make actually
LaTeX produce these scores, and then

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eventually they realized that's not going
to work, we should actually write this as

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a dedicated program in C or C++ (I don't
remember which one), but the syntax kind

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of stayed similar, at least, in
remembrance of that. And let's go back to

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a bit more syntax, as I said, in relative
mode the notes try to stay close together,

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for example if I would just write C after
this G, it would be the upper C up here,

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because that's closer than the lower C
down here, and to get the lower C, which

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is correct in this melody (if you can
identify it that's an Easter Egg for you),

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I put a comma after it, and to then jump
back to the upper G instead of the lower

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one, I put an apostrophe after it, which
depending on the font – in this one it

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works really well, it's kind of the same
character, just at the bottom and at the

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top the line. In German the apostrophe is
also sometimes called the Hochkomma, the

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upper comma, so it kind of makes sense
that you have these two characters to jump

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up and down between octaves, and then you
start to get a feel eventually when you

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need them and when you don't need them.
But otherwise you can just compile your

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LilyPond code as often as you want and see
if it's right or not, because it doesn't

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take that long. And if you need to modify
the notes further, so if you have flat or

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sharp notes, you can teach LilyPond to
understand “G sharp”, for example, but no

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one will understand your score, because
the standard notation in LilyPond is to

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add either an -is or an -es to the end of
the note, which is exactly what these

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notes are called in German, which is very
convenient if you're German, like me – the

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manual says it's Dutch notation or
something – so fis means the F sharp, but

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what's important is, this doesn't
literally mean: put an F and then put a

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sharp right in front of it, it means,
logically, in the music, there's an F

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sharp, but then LilyPond can look, for
example here it just puts an F, because

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the F sharp is already part of the key
signature, this whole snippet is in B

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minor, so it has to have… no, it's in E
minor, sorry, so it has to have F sharp

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already and we don't need to put one here.
On the other hand, here we have an F, and

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in the syntax, in the input that's just an
F, but then LilyPond knows, because the

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key signature has an F sharp, it actually
needs to put a natural sign here to cancel

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that out. So what you put in is kind of
the logical, real music, so to speak, and

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then it's LilyPond’s job to figure out,
where do I need to put these accidentals,

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where do I need to put these natural
signs, and this depends even on which

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century’s style you're trying to emulate
and which instrument, like sometimes these

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things are in parentheses and sometimes
they're not, but in general all of this is

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LilyPond’s job, you put in just the music
and LilyPond makes a beautiful score for

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you, that's the job, at least. If that
doesn't work out, you can tweak the

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output, and here I have some… a bit
sillier tweaks, for example I wanted a

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larger note head, for some reason, and the
note head is a character in a special font

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which LilyPond ships and embeds in this
PDF file, and if I say, I would like to

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add 4 to the font size, then I get a
larger note head, at least for this one

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note. Or I can say I would like the color
of all the note heads to be in dark red

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now, or this tie, which would normally be
downwards, like this one, it should now go

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upwards, because I've overridden it here,
and I can even say – so this tie is

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actually a cubic Bezier curve, so it's
going to have four control points, and I

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would like to add these four pairs of
offsets to the four control points, to

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make this kind of looping shape – that's
obviously very silly, but sometimes this

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can be useful, like if you have a score
where you have a long… articulation bow

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(I'm not sure what it's called in English,
actually), but this kind of thing over a

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long period of notes, where it makes like
a Z shape or an S shape, and LilyPond

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can't figure that out by itself, then you
can tell it, I would like the curve to

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look exactly like this, and kind of tweak
the output as much as you want. And you

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can actually go even further than this –
does anyone in the audience recognize this

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kind of syntax here? This kind of –
(audience member: Lisp!) Yes! Lisp, it is

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a dialect of Lisp called Scheme, so you
can embed whole Scheme programs in your

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score, so here I've said the color of each
stem should be controlled by this lambda,

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this anonymous function, which takes a
graphical object, in this case that's

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going to be the stem, and compare the
direction of that to “up”, if it's “up”,

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then return red, otherwise return blue, so
now I have a score where all the stems are

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blue if they point down and red if they
point up, which is completely pointless,

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but it's very funny. And you can go much
further than this, like, this is some

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monstrosity I wrote because I wanted to
have this score, where you can see, in the

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right hand, here, you have the same notes
twice, once in the baseline and then one

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octave higher, and it's just always one
octave higher, and for some reason I could

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not be bothered to actually add the second
note to each of the eight chords here,

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which would have taken, like, two minutes
at most, and instead I spent, like, one

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and a half hours putting together this
code, which takes an arbitrary melody and

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goes through it and for each note creates
a copied note which is somewhere here,

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yeah, it creates a copy of the note, then
sets the pitch to something else and

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copies some of the articulations but not
others, so this has a second tie here but

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it should not have a second fermata sign,
and in the end you have this function and

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you can even put it on StackOverflow or
something, and that kind of represents

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what I really like about LilyPond, that it
represents this whole spectrum between

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just simple music transcription and full-
blown programming, so if I get home at the

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end of the day, and I'm really tired and
don't have much mental capacity, I can

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just take some public domain score and
transcribe it and just say, this is a D,

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this is an F sharp, this is a quarter
note, and so on, and it doesn't take much

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work, but if I want, if I feel up to it or
if I want to have some fun, then I can

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also do the whole programming thing and
write monsters like this and completely

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bend the score to my will, make it look
exactly how I want to, and that's what I

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find really neat about LilyPond, and if
you want to find out more about that,

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there are two manuals here, they're really
well written, I basically read them front

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to back a while ago, and they have lots of
examples as well. The LilyPond snippet

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repository is even cooler, it's just a
huge collection of tiny snippets of

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LilyPond code, and all of them are CC0, so
you can use them however you want without

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worrying about attribution or anything,
and you can even try it out in your

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browser, on lilybin.com, without
installing anything, and if you're

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wondering, “wait, doesn't that mean I'm
running arbitrary code on someone else's

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computer?” – it's not my computer,… I
don't know, knock yourself out, I guess,

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but that's all I have already, I'm out of
time, but thank you for indulging me!

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<i>applause</i>

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<i>postroll music</i>

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