tur-tidal

A Tidal Cycles-inspired mini-notation parser and pattern library for Turmeric. tur-tidal parses the compact mini-notation used by Tidal Cycles into an in-memory pattern tree, evaluates that tree at any cycle number to produce a flat list of timed events, and renders the result as a plain-text event table, a raw sclang Pbind.new(...) expression, or a scscm pbind form for use with the tur-scscm spice.

Mini-notation reference

Syntax	Meaning
`bd sd cp`	Sequence: three equal-duration steps per cycle
`[bd sd] cp`	Subsequence: bd and sd share the first half-cycle slot
`<60 62 64>`	Alternating: one value per cycle, advancing each cycle
`bd*2`	Repeat: bd twice within its slot
`bd/2`	Slow: bd spans 2 cycles
`bd(3,8)`	Euclidean rhythm: 3 pulses distributed across 8 steps
`bd@2`	Weight: bd takes twice as much time in a sequence
`~`	Rest: empty slot (no event produced)

Note names (c4, d#3, bb5) are resolved to MIDI numbers by note->midi. Raw integers (60, 72) pass through as MIDI directly. Drum names (bd, sd, cp) pass through as string values in events and are not converted to MIDI (their note->midi result is -1, so they are filtered out of render-sclang / render-pbind MIDI arrays).

Quick example

(let [r (parse-notation "c4 [d4 e4] f4")]
  (let [p (ok-val r)]
    (println (render-sclang p "piano"))
    (notation-free p)))

#lang sweet-exp
let [r parse-notation("c4 [d4 e4] f4")]
  let [p ok-val(r)]
    println $ render-sclang p "piano"
    notation-free(p)

Output:

(Pbind.new([\instrument, "piano", \midinote, Pseq.new([60,62,64,65],inf), \dur, Pseq.new([0.250,0.125,0.125,0.250],inf)])).play;

Modules

tidal/event

Low-level event struct (onset, dur, value) and the note->midi parser.

event-new onset dur value -- allocate an event
event-onset e -- onset fraction (0.0 to 1.0)
event-dur e -- duration fraction (0.0 to 1.0)
event-value e -- raw string value
event-free e -- free the event
note->midi value -- parse note name or integer to MIDI number (-1 for rest)

tidal/notation

Mini-notation parser and evaluator.

parse-notation text -- parse text into a pattern handle; returns ok(p) or err(msg)
notation-free p -- free a pattern handle
pattern-events p cycle -- evaluate pattern at cycle, returns cons list of events

tidal/pattern

Higher-level combinators that wrap an existing pattern handle.

pattern-fast p n -- speed up by factor n
pattern-slow p n -- slow down by factor n
pattern-stack p1 p2 -- overlay: events from both patterns per cycle
pattern-cat p1 p2 -- concatenate: alternate p1/p2 each cycle
pattern-rev p -- reverse event order within a cycle
pattern-every n f p -- apply transformed pattern f every nth cycle
pattern-degrade p prob -- randomly drop events with probability prob
pattern-free p -- free a combinator pattern

tidal/render

Render a pattern to text.

render-events p cycle -- plain-text table: one onset dur value line per event
render-sclang p instrument -- sclang Pbind.new(...).play; string
render-pbind p instrument -- scscm (. (pbind ...) play) string

Dependencies

tur-scscm (optional) -- provides the scscm compiler used by render-pbind output. tur-tidal produces the scscm text but does not require tur-scscm to be loaded in order to render it. The tur-scscm dependency is marked :optional true in build.tur.

Building

just build
just test

License

MIT

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