Every way to build a Sequencer and send it to an instrument. Four notations for the same idea,
and one message — to: — that puts any of them on stage.
1. The shape of every pattern
In Coypu a sound is produced by attaching a Sequencer to an instrument name
— an ordinary Pharo symbol such as #kick or #snare. The Sequencer
says when to trigger; the engine behind your
Performer decides how that sounds.
Every creation method in this guide follows the same two-part shape:
"build a pattern → send it to an instrument"
<pattern expression> to: #instrumentName.A Sequencer sent to a key that is already occupied replaces what was there, which is what makes live editing work — re-evaluate a line and the part changes at the next step.
2. Binary arrays
The most literal notation: an array of 1s and 0s. Send it
asSeq to turn it into a Sequencer.
#( 1 0 0 1 0 0 0 0 ) asSeq to: #kick.| Element | Meaning |
|---|---|
| 1 | Trigger the instrument on this step |
| 0 | Rest — do not trigger |
"four-on-the-floor kick"
#( 1 0 0 0 1 0 0 0 1 0 0 0 1 0 0 0 ) asSeq to: #kick.
"snare on beats 2 and 4 of a 16-step grid"
#( 0 0 0 0 1 0 0 0 0 0 0 0 1 0 0 0 ) asSeq to: #snare.
Array length is free — 8, 16, 32 all work, and a shorter array simply loops sooner. The
related asRhythm converts an array into a Rhythm object rather than
a Sequencer, which is what the named rhythms in §3 answer.
asSeq and not just the array
asSeq builds a Sequencer with sensible defaults around your gates: one note per
trigger at MIDI 60, a duration derived from the spacing of your triggers, and a gate time of
0.8. Those defaults are what you override with notes:, durations:
and the rest — see Player & Message API.
3. Named rhythms
Coypu ships 31 named rhythms drawn from musical traditions around the world. Send
asRhythm to a symbol to get a ready-made Sequencer:
#rumba asRhythm to: #conga.
#cumbiaClave asRhythm to: #conga.
#banda asRhythm to: #kick.asRhythm on a symbol always gives you 16 steps
#trueAksak asRhythm is 16 steps of a 13-step pattern, which truncates mid-cycle.
To get a whole number of cycles, call the rhythm on an integer instead —
13 trueAksak — as in §3.1. The
Rhythm Library lists every pattern's true length.
3.1 Shorthand: to: on a symbol
You can skip asRhythm and send to: straight to the symbol:
#plena to: #conga.
#banda to: #kick.The more useful form sends the rhythm name to an integer, which sets the length explicitly and is the notation used throughout this manual:
16 claveSon to: #conga.
13 trueAksak to: #perc. "13 steps — a whole cycle"
32 jungleKick to: #kick. "jungle patterns are 32 steps"3.2 Listing what is available
Rhythm list. "Cmd-I / Ctrl-I to inspect the result"
This returns a Dictionary of every selector carrying the
<rhythmCreation> pragma, with its source comment. The
Rhythm Library is generated from that same pragma, with
step visualisations and notes on where each pattern comes from.
4. Hex patterns
A compact notation: each hexadecimal digit encodes four steps. Four digits give a 16-step pattern, eight digits give 32, and so on — the length follows the length of the string.
'F000' hexBeat to: #kick.
"F = 1111, 0 = 0000 → triggers on the first 4 steps of 16"
'020F' hexBeat to: #snare.
"0=0000 2=0010 0=0000 F=1111 → a syncopated pattern"
'FFFF' hexBeat to: #ch.
"all 16 steps active — sixteenth-note closed hat"| Hex digit | Binary | Meaning |
|---|---|---|
| 0 | 0000 | Four rests |
| 8 | 1000 | Only the first step |
| A | 1010 | Every other step |
| F | 1111 | All four steps |
Hex is how Coypu stores the three jungle patterns internally — jungleKick is
'88000000', eight digits and therefore 32 steps. It is worth learning for
exactly that reason: long patterns stay readable.
5. Grid helpers
Several rhythms are not patterns so much as grid divisions. They take the length as the receiver and fill it according to a rule:
| Expression | Fills | Triggers |
|---|---|---|
| 16 semiquavers | Every step | 16 |
| 16 trigs | Every step — identical to semiquavers | 16 |
| 16 quavers | Steps 1 and 3 of each group of 4 | 8 |
| 16 downbeats | Every 4th step | 4 |
| 16 upbeats | The 3rd step of each group of 4 | 4 |
| 16 rests | Nothing | 0 |
16 quavers to: #ch.
16 semiquavers to: #oh.
16 downbeats to: #kick.
16 upbeats to: #ch.8 quavers is eight steps containing four triggers, and
32 quavers is thirty-two steps containing sixteen. Only
semiquavers and trigs put a trigger on every step, which is why
their step count and trigger count happen to match.
These are the fastest way to get a bed going, and a good base to modify: start with
16 semiquavers on a hat and thin it out with
an offset or a random gate.
6. Joining and repeating
Pharo's comma concatenates collections, and Coypu extends it to Sequencers. Use it to build a longer pattern out of shorter ones:
"16 quavers followed by 16 semiquavers → a 32-step hat part"
16 quavers , 16 semiquavers to: #oh.
"a named rhythm followed by a hand-written array"
#rumba asRhythm , #( 1 0 1 0 ) asSeq to: #conga.
* repeats a Sequencer, and times: does the same thing with a
keyword:
8 downbeats * 4 to: #kick. "32 steps: the 8-step pattern four times"
(8 downbeats times: 4) to: #kick. "the same thing", concatenates the gates, the notes and the durations together, so a joined
Sequencer keeps whatever pitches and lengths each half carried. That makes it a real
arrangement tool rather than only a rhythm one.
7. Adding notes
A rhythm on its own plays one repeated note. notes: gives it pitches, as MIDI
note numbers:
(16 claveSon notes: #( 36 38 42 46 38 )) to: #perc.Many named rhythms also take the notes inline, as a string, which avoids the parentheses:
16 claveSon: '36 38 42 46 38' to: #perc.Not every rhythm has that variant. The Rhythm Library tags the ones that do. Notes are consumed one per trigger and wrap around, so you need no more notes than the pattern has triggers — fewer is fine and will cycle.
For melodic writing, string notations carry rests and durations as well as pitches — see Melody & Scales and Rhythms: Advanced.
8. Pattern length and the loop point
Coypu has a single global transport. Every Sequencer wraps independently at its own length, which means two patterns of different lengths drift against each other and realign only at the least common multiple of the two.
That is a feature — it is how you get polymetre for free:
16 downbeats to: #kick. "16 steps"
13 trueAksak to: #perc. "13 steps — realigns after 208"But it is also the commonest source of a pattern that sounds wrong: give a 13-step rhythm a length of 16 and it truncates mid-cycle every time round. When you want a rhythm to sound as intended, give it a multiple of its own length — the Rhythm Library lists every one.
10. Troubleshooting
The pattern evaluates but nothing plays
The transport is not running, or no Performer is set. p play, and check
Setup §4.
8 quavers gave me four hits, not eight
The receiver is the step count, not the trigger count — §5.
A named rhythm sounds cut off or lurches every cycle
Its length does not divide the length you gave it. Use a multiple of the pattern's own length — §8.
16 bomba: '36 38' raises doesNotUnderstand
A bug in the Coypu source — bomba: never assigns its pattern. Plain
16 bomba works; add notes with notes: instead. See the
Rhythm Library troubleshooting.
Sending a second pattern to the same instrument replaced the first
That is intended — one Sequencer per key. Use a second instrument name, or join the two
patterns with , — §6.
My hex string produced more steps than I expected
Each digit is four steps, so eight digits is 32 — §4.