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Pattern Methods

This content is for v0.7. Switch to the latest version for up-to-date documentation.

Method Reference

Method	Description
`fast(factor)`	Speed up pattern by factor
`slow(factor)`	Slow down pattern by factor
`transpose(semitones)`	Pitch shift notes
`reverse()`	Reverse pattern order
`rotate(steps)`	Rotate pattern by steps
`stack(other)`	Stack with another pattern (parallel)
`cat(other)`	Concatenate with another pattern
`concat(other)`	Alias for `cat`
`degrade(probability)`	Randomly drop notes (0-1)
`euclid(hits, steps)`	Apply Euclidean rhythm
`euclid(hits, steps, rotation)`	Euclidean with rotation
`nudge(offsets)`	Per-step timing offsets (array of cycle fractions)
`swing(amount)`	Swing feel — shifts odd-indexed events forward
`humanize(amount)`	Deterministic random timing variation (plus/minus amount)
`map(fn(note))`	Transform each note (MIDI pitch)
`map_with_timing(fn(note, start, dur))`	Transform with timing info
`at(index)`	Get element at index
`iter()`	Create infinite iterator over events
`describe()`	Get human-readable description
`length()`	Get number of elements

Examples

let pat = [C4 D4 E4 F4];

// Speed control
pat.fast(2);                   // Double speed
pat.slow(2);                   // Half speed

// Pitch manipulation
pat.transpose(12);             // One octave up
pat.transpose(-5);             // Down a fifth

// Reordering
pat.reverse();                 // [F4 E4 D4 C4]
pat.rotate(1);                 // [D4 E4 F4 C4]

// Combining patterns
pat.cat([G4 A4]);              // Concatenate sequentially
pat.stack([G4 A4]);            // Play simultaneously

// Degradation and rhythm
pat.degrade(0.3);              // 30% chance to drop each note
[C4].euclid(3, 8);             // Euclidean rhythm

// Microtiming (step-relative fractions)
pat.nudge([0, 0.25, 0, -0.1]);  // Per-step offsets
pat.swing(0.25);                 // Swing feel on odd events
pat.humanize(0.1);               // Subtle random timing variation

// Indexing
pat.at(0);                     // First element as pattern
pat[2];                        // Third element (same as .at(2))

// Mapping
pat.map(fn(note) { return note + 12; });  // Transpose up octave
pat.map_with_timing(fn(note, start, dur) {
    if start == 0.0 { return note + 12; }  // Accent downbeat
    return note;
});

// Iteration (infinite -- always use .take()!)
let events = pat.iter().take(8).collect();

// Pattern-patterning -- parameter varies per cycle
pat.fast([1 2 3]);             // Cycles through 1x, 2x, 3x speed
pat.transpose([0 7 12]);      // Shift by 0, 7, 12 semitones each cycle
pat.degrade([0.0 0.5 0.9]);   // Increasing degradation across cycles

See Also

Pattern Basics - Pattern fundamentals
Euclidean Rhythms - Algorithmic pattern generation