[PD] Ability to access error messages from patch

IOhannes m zmoelnig zmoelnig at iem.at
Thu Jun 17 13:25:32 CEST 2021

(argh. one of those emails that are lingering opened on my desktop, and 
were never sent...here you go:)

On 6/15/21 12:32 AM, Christof Ressi wrote:
> # error outlets
>> Let's say.... if we were to consider adding some sort of "standard 
>> outlet" for errors, how many objects are we talking about? I assume 
>> not every object but perhaps those which read/write files and the net 
>> objects? That's not so many, really.
> I agree. We should ask ourselves if it is really necessary to add some 
> generic error reporting mechanism to Pd. Error outlets are certainly the 
> most simple and most easy to understand solution from a user perspective.


in any case: ith the error outlet i think we really want a possibility 
to both:
- get the error string as well
- suppress the internal error message (as it can now be handled on a 
patch level)

> # errno object
>> As Pd is more or less structured after C to some degree, I like the 
>> idea of formalizing something like errno and simply using the standard 
>> defined error numbers
> When proposing the [errno] object, I did not mean that it would output 
> the C errno, but rather custom error codes as defined by each object.

which of course could happen to be the same as the system error numbers 
- as long as they are not system *specific*.
iirc POSIX defines error names, but not their values.
so probably its better to come up with your own error numbers from the 

> # (sub)patch errors
> Another disadvantage is that you need to have the object in a dedicated 
> subpatch, otherwise you have to use complicated [spigot] logic to deal 
> with crosstalk between several objects.

again, i think this is not necessarily a bad thing as it nicely groups 
the objects that one wants to monitor.

Pd is a data flow language and I thikn the per-canvas paradigm maps well 
to the idea of data "passing through a danger zone" - which it can also 
leave as well.

 > think IOhannes called them exceptions, but I would avoid that naming
 > as I assume it will not halt or crash Pd if the error is not handled.

well, there are uncatchable exceptions.

anyhow, i used that naming here as an input for brainstorming and for 
the sake of an analogy.

anyhow, whatever the name, i think we also should not use [catch] as the 
proposed object name ;-)

however, I do like oliver's idea of hooking up such a [catch]-like 
object in the object-tree.


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