Type Alias AUImplementorValueFromStringCallback 

pub type AUImplementorValueFromStringCallback = *mut DynBlock<dyn Fn(NonNull<AUParameter>, NonNull<NSString>) -> AUValue>;

Available on crate features AUAudioUnitImplementation and AUParameters and block2 only.

A block called to convert a string to an AUParameter’s value.

See also Apple’s documentation