Re-evaluating an Ndef with a syntax error keeps the old graph running with no audible indication

JITLib Ndef is designed for live resilience: if a re-evaluation fails due to a syntax error, the previous definition continues running uninterrupted and the audio does not drop. However, the failed edit has no effect. The only indication is a red error message in the SC post window. The same behaviour applies to Strudel and Glicol, which both keep the last valid state on parse failure. The discipline for live coding: always watch the post window; a silent non-change means the edit failed, not that the change had no audible effect.

Examples

Ndef(\a, { SinOsc.ar(440 *** 0.2) }); // syntax error // Old Ndef keeps playing; post window shows red error

Assessment

You re-evaluate an Ndef and the sound does not change. How do you determine whether your edit took effect or was silently rejected?