Envelopes

Envelopes use their own literal: levels and durations alternate.

env[0 5ms 1 120ms 0.4 | 600ms 0]

Starts at 0, reaches 1 in 5ms, 0.4 in 120ms, holds at the sustain point (|), and on release takes 600ms to reach 0.

Rules

Any number of segments; two levels or two durations in a row is an error.
| marks the sustain point. No | means a one-shot that plays through.
Durations in any time unit, mixed freely. Beat segments follow tempo changes.
Curves are methods on the duration: 900ms.exp, 5ms.log, 600ms.curve(-4).
Levels can have any unit, as long as they all match: hz, db, or unitless.
Releasing mid-segment starts release from the current level.
.loop repeats the shape.
adsr(attack:, decay:, sustain:, release:) is a named-argument shortcut for the same idea.

Examples

env[0 3ms 1.2 40ms 0.8 200ms 0.6 | 100ms 0.3 2sec 0]   // multi-segment, two-stage release
env[0 4beats.log 1 | 2beats 0]                        // tempo-synced swell
cut = env[200hz 10ms 6khz 300ms.exp 900hz | 400ms 200hz]
wob = env[0 (1/8 beat) 1 (3/8 beat) 0].loop