A JITLib proxy is a placeholder defined by its valid sources, its contexts of use, and a default source

JITLib consists of placeholders (server-side and client-side proxies) and schemes of access. A placeholder is a ‘role’ with a certain behaviour that can be fulfilled by certain objects. The three aspects of any placeholder are: the set of elements that can be its source; the set of contexts in which it can be used; and a default source used when none is given. This framing is what lets a running proxy accept a new source live — a SynthDef, a Function, or a pattern — as long as the new value is a valid source for that placeholder’s role.

Examples

Ndef(\pad, { |freq=440| SinOsc.ar(freq) * 0.3 }).play // Function source Ndef(\pad).set(\freq, 220) // valid context: setting a named control

Assessment

Name the three aspects that define a JITLib placeholder, and say which one is violated if you try to assign a non-UGen value as an Ndef’s synthesis source.