Validation & Warnings

The compiler runs semantic analysis after parsing and reports errors and warnings.

Errors (compilation stops)

Check	Description
Undefined instrument	PLAY / BEAT references an instrument not defined
Undefined sequence	PLAY_SEQUENCE references a sequence not defined
Undefined pattern	PLAY_PATTERN references a pattern not defined
Invalid note name	Note doesn't match the expected pattern
Negative duration	Beat duration <= 0
Volume out of range	Volume not 0–255
Velocity out of range	Velocity not 0–255
Negative ADSR	Any ADSR parameter < 0
LOOP count <= 0	Loop must repeat at least once
Cutoff out of range	CUTOFF not 20–20000
Resonance out of range	RESONANCE not 0–255
Reverb out of range	REVERB not 0–255
Delay time out of range	DELAY time not 0–2000
Delay feedback out of range	DELAY feedback not 0–255
Pan out of range	PAN not 0–255
BPM change out of range	Dynamic BPM not 1–300
SWING out of range	SWING not 0–100
HUMANIZE out of range	HUMANIZE not 0–50
FADE duration invalid	FADE_IN / FADE_OUT not 1–64 beats
PLUCK on DRUM	PLUCK wave cannot be used with DRUM instruments
LFO rate out of range	LFO rate not 0.1–20.0
LFO depth out of range	LFO depth not 0–255
VOICES out of range	VOICES not 1–4
DETUNE out of range	DETUNE not 0–100
CHORUS out of range	CHORUS not 0–255
DETUNE without VOICES	DETUNE > 0 requires VOICES > 1
Per-note REVERB out of range	REVERB override not 0–255
Per-note DELAY time out of range	DELAY time override not 0–2000
Per-note DELAY feedback out of range	DELAY feedback override not 0–255
Per-note CUTOFF out of range	CUTOFF override not 20–20000
VELOCITY_CURVE velocity out of range	Start or end velocity not 0–255
VELOCITY_CURVE note_count out of range	Note count not 1–128
TIME_SIGNATURE beats out of range	Beats not 1–16
TIME_SIGNATURE division invalid	Division not one of 1, 2, 4, 8, 16
BEAT exceeds bar length	BEAT position exceeds the declared TIME_SIGNATURE bar length
REVERB DECAY out of range	REVERB DECAY not 100–10000
REVERB ROOM out of range	REVERB ROOM not 0.0–1.0
POLYPHONY out of range	POLYPHONY not 1–8
BELL on DRUM	BELL wave cannot be used with DRUM instruments
BPM OVER target out of range	Target BPM not 1–300
BPM OVER beats out of range	Ramp beats not 1–64

Warnings (compilation continues)

Check	Description
Very short ADSR	ADSR < 5 ms (control rate is ~16 ms/step)
Note outside piano range	MIDI < 21 or > 108
Too many synths	> 4 synths (ATmega328 has 2 KB RAM)
Fast BPM	BPM > 300 may exceed AVR timing
Non-standard audio rate	Not 16384 or 32768
Beat outside bar	Beat position > bar length
PLAY_TOGETHER < 2 items	Use PLAY_SEQUENCE / PLAY_PATTERN directly
GLIDE on DRUM	Portamento has no effect on drum instruments
GLIDE > 1000	Very long glide may sound unnatural
GLIDE on PLUCK	Portamento doesn't apply well to plucked strings
LFO rate > 10	LFO rate approaches audio range
LFO VOLUME on DRUM	Volume LFO on drum has limited effect
LFO PITCH on DRUM	Pitch LFO has no effect on drums
LFO CUTOFF on DRUM	Cutoff LFO on drum has limited effect
LFO PAN on DRUM	Pan LFO on drum has limited effect
LFO PAN (AVR target)	LFO PAN requires ESP32 with I2S DAC — won't compile on AVR
Per-note CUTOFF without instrument CUTOFF	Override has no effect if instrument lacks CUTOFF
VELOCITY_CURVE extends beyond sequence	Note count exceeds remaining PLAY events in sequence
>2 CUTOFF LFOs (AVR)	Multiple filter LFOs may exceed AVR RAM budget
VOICES > 2	Uses significant RAM on AVR targets
VOICES on DRUM	Unison voices have no effect on drums
DETUNE > 50	Large detune may sound out of tune
Note outside KEY	Note pitch class not in declared scale
High SWING	SWING > 75 is extreme, may sound unmusical
High HUMANIZE	HUMANIZE > 30 creates very loose timing
No TIME_SIGNATURE with high BEAT	BEAT position > 4 used without explicit TIME_SIGNATURE — assumes 4/4
LEGATO on DRUM	LEGATO has no effect on drum instruments
High total polyphony	Total POLYPHONY across all instruments exceeds 8 (AVR RAM)
BPM OVER short ramp	BPM ramp < 2 beats may sound like a glitch