Hello, I’m new to the forums and very new to Pd so please excuse me if this is a trivial question.

I am looking to write an iOS app (in Swift, no less) that will dynamically load an instrument, such as a guitar, patched in Pd. I have played with the iOS samples with success and know that I can call PdBase sendFloat to send values to my named ”$0-" receive objects.

What I would like to know is:

1. can my application determine at run time how many dollarZero receive objects there are in the Pd patch, and

2. can the application determine the name of the dollarZero receive object at run time. In other words, ask the patch for an array of available dollarZero receive objects.

What I want to do is load an instrument, say a guitar, and then determine at run time that the instrument has receive objects named "pitch", "tone", "portamento”, etc. The app would then create iOS GUI objects to facilitate the app user to set values for these objects.

If I could do this I’d be very happy. If in addition to this I can also obtain minimum and maximum values for the receive objects I’d be ecstatic.

Also, is there a difference between receive objects named with "$0-" and those without?

Thanks!

-Allan

$0 gets replaced with a number that is unique to a given abstraction-instance. The point is that if I load multiple instances of the same abstraction, the send message will go to only its own instance and not the others. So in this case, I would imagine that you would want to use a regular send without $0, so that it can be received outside of its abstraction instance.

I don't think that there is an easy way to count objects within PD. However, you can still accomplish what you want to do by sending a message that has all the relevant information in it. For instance, in your guitar abstraction you have this:

 [loadbang]
 |
 [1 1 0 1 (
 |
 [send load-values]

which means "pitch is on, tone is on, portamento is off, filter is on"

and in your drums abstraction you have this:

 [loadbang]
 |
 [1 0 1 0 (
 |
 [send load-values]

which means "pitch is on, tone is off, portamento is on, filter is off"

etc.

Then in your parent patch you can have [receive load-values] and unpack the message.

I'm assuming that you will only ever have one instrument loaded at once. If not then things get more complicated. Nevertheless, I think that creating a message system is the way to go.

@LiamG Thank you! You know, it never really occurred to me what abstraction versus instance meant until I read this reply. Now it's obvious, just like in object programming. So in a polyphonic instrument, pitch is sent to a voice $0- instance, whereas tone would be sent to the "class" abstraction.

I will investigate your list idea further but it would still be desirable to query the patch for configuration receive messages. The list idea will require all instruments for my app to adhere to a static set of configuration messages but may be the only option.

-Allan