norns script reference

This script reference is a supplement to the complete norns API. Here, you’ll find examples which explore single components of the API, which can be copied/pasted into your own scripts and manipulated for your needs. These examples assume familiarity with the scripting concepts covered in the norns studies.

To access the complete norns API, you can either:

• connect to maiden and navigate to norns.local/doc in your browser
• visit the static API

modules

Note: Many module names link to extended reference examples, which illustrate how to use the commands in different contexts. Any module name followed by (api) links to the static API.

folder structure

Scripts are located in ~/dust/code/, and are what make norns do things. A script consists of at least a Lua file but can additionally also contain supporting Lua libraries, SuperCollider engines and data.

myscript/
  myscript.lua -- main version, shows up as MYSCRIPT
  mod.lua -- alt version, shows up as MYSCRIPT/MOD
  README.md -- main docs/readme
  data/
    myscript-01.pset -- pset, loaded via params:read(1) or via menu
  lib/
    somelib.lua -- arbitrary lib, imported via require 'lib/somelib'
    some-engine.sc -- engine file
    some-engine.lua -- engine lib, require lib/some-engine'
  docs/ -- more documentation, won't be shown in SELECT
    more-docs.md

basic script

-- scriptname: short script description
-- v1.0.0 @author
-- llllllll.co/t/22222

engine.name = 'PolySub'

function init()
  -- initialization
end

function key(n,z)
  -- key actions: n = number, z = state
end

function enc(n,d)
  -- encoder actions: n = number, d = delta
end

function redraw()
  -- screen redraw
end

function cleanup()
  -- deinitialization
end

setting minimum required version

Each norns update brings new features, both for scripting and general usability. If you share a script which relies on the features of a particular norns update, you can specify a minimum version requirement which will display a message on the norns screen if the script is loaded on a previous version of the software.

To specify a minimum version required, set norns.version.required to the YYMMDD value before the init() of your script, eg:

-- minimum required version check

norns.version.required = 221214 -- can be a number or string, formatted YYMMDD

function init()
  print('hello, welcome to the script')  
end

If this script is loaded on a norns running software earlier than 221214, you’ll see this on the norns screen:

error: version 221214 required
try 'SYSTEM > UPDATE'

And this will print to maiden:

### SCRIPT ERROR: version 221214 required
### try 'SYSTEM > UPDATE'
### or check for new disk image

helpful system commands and variables

There are some commands and variables which are helpful for common scripting tasks. Please note that while these tables may contain additional commands and variables, any not mentioned in this section will not be useful for standard scripting.

These semicolon-preceded commands are shortcuts which are run from maiden directly:

The norns table contains useful system commands and variables:

The norns.script table contains functions for script lifecycle management:

The norns.state table contains useful state data:

The _path table contains useful aliases for common file-paths:

libraries

Lua libraries can be used by using include("path/to/library"). Remember to not include .lua in the library name.

local libraries

include() will first look in the directory of the current script. This allows using relative paths to use libraries local to the script. For example, with the following structure:

myscript/
  myscript.lua
  lib/
    somelib.lua

myscript.lua can include somelib.lua using:

include("lib/somelib")

third-party libraries

Third party libraries can be included using their full path starting from the ~/dust/code/ directory. For example, with the following structure in ~/dust/code/:

myscript/
  myscript.lua
  lib/
    somelib.lua
otherscript/
  otherscript.lua
  lib/
    otherlib.lua

myscript.lua can include otherlib.lua using:

include("otherscript/lib/otherlib")

engine

Specify an engine at the top of your script. See the engine docs for more details.

engine.name = 'PolySub'

If you want to use an engine from another project make sure to install that project first. If the engine comes with an accompanying Lua file make sure to import it:

engine.name = 'R'

local R = require 'r/lib/r'

• engine.list_commands() shows the commands.

For example to set the command cutoff to 500:

engine.cutoff(500)

To see a list of all locally installed engines:

tab.print(engine.names)

screen

The screen API handles drawing on the norns screen. See the screen docs for more details.

function redraw()
  screen.clear()
  screen.move(10,10)
  screen.text("hello world")
  screen.update()
end

metro

The metro API allows for high-resolution scheduling. See the metro docs for more details.

re = metro.init()
re.time = 1.0 / 15
re.event = function()
  redraw()
end

• re:start(), starts metro.
• re:stop(), stops metro.

paramset

The paramset API allows to read and write temporary data and files. See the paramset docs for more details.

A parameter can be installed with the following:

params:add{
  type = "number",
  id = "someparam",
  name = "Some Param",
  min = 1,
  max = 48,
  default = 4,
}

• params:set(index, value), writes a parameter.
• params:get(index), reads a parameter.

system globals

Do not overwrite these variables. Doing so may break things.

System globals:

_G, _VERSION, assert, bit32, collectgarbage, dofile , error, getmetatable, ipairs, io, load,
loadfile, next, math, os, pairs, pcall, print, rawequal, rawget, rawlen, rawset, require,
select, setmetatable, tonumber, tostring, table, type, utf8, xpcall

norns globals:

_menu, _norns, _path, _startup, arc, audio, cleanup, clock, controlspec, coroutine, crow,
debug, enc, engine, grid, hid, include, inf, key, metro, midi, mix, norns, osc, package,
params, paramset, paths, poll, redraw, screen, softcut, string, tab, util, wifi

devices

grid

grid.connect(n) to create device, returns object with handler. See the grid docs for more details.

g = grid.connect()

• g:led(x, y, val), sets state of single LED on this grid device.
• g:all(val), sets state of all LEDs on this grid device.
• g:refresh(), update any dirty quads on this grid device.
• g.key(x, y, state), key event handler function.

arc

arc.connect(n) to create device, returns object with handler. See the arc docs for more details.

a = arc.connect()

• a:led(ring, x, val), sets state of single LED on this arc device.
• a:all(val), sets state of all LEDs on this arc device.
• a:segment(ring, from, to, level), creates an anti-aliased point to point arc - segment/range on a specific LED ring.
• a:refresh(), updates any dirty quads on this arc device.
• a.delta(n, delta), encoder event handler function.

midi

midi.connect(n) to create device, returns object with handler. See the midi docs for more details.

m = midi.connect()

• m:note_on(value,velocity,channel), sends note_on message.
• m:note_off(value,velocity,channel), sends note_off message.
• m.event, midi event handler function.

hid

hid.connect(n) to create device, returns object with handler. See the hid docs for more details.

h = hid.connect()

osc

Send networked data via Open Sound Control. See the osc docs for more details.

• osc.send(to, path, args), sends osc event.
• osc.event(path, args, from) handler function called when an osc event is received.

crone

pdf version

contribute

Contributions to the script reference are welcomed + we are very grateful for any assistance covering these topics.

Have questions about how to contribute? Please feel free to email help@monome.org and we can collaborate!

Many thanks to @fardles (site) for building the reference pages for er, fileselect, musicutil, textentry, and ui.