[PD] Request - Deleting struct instances, progress?

Christof Ressi christof.ressi at gmx.at
Tue Jan 3 12:00:19 CET 2017

> but what is the
> [scalar] object supposed to do? Is it just a specific instance of a
> struct in the linked list? 

What it does is create its own subpatch and append a single scalar of a given template (struct). This way it's a bit like the table object. I often use it when I don't care about the graphical representation and just want to use a struct as a container of heterogenous data. I think it's meant to get an interface similar to [array] and [text] in the future, but even in its current rudementary form it's quite useful.

Regarding your request of a 'delete' method:

We can already delete scalars from the glist by selecting their graphical representation in the subpath and hit `del', just with any other object. Pointers will get marked invalid (error message about pointer being 'empty' or 'stale') and therefore stay safe. So the functionality is there, we just need a way to delete a scalar by pointer. 

in the meantime, here's a little hack how to delete specific scalar instances (as long the scalar has a drawing instruction and is visible + editable). get the scalar's x + y coordinates with [get], then send following message to the subpatch containing the scalar: 
[mouse x y 1 0, mouseup x y 1, key 1 8 0(


> Gesendet: Dienstag, 03. Januar 2017 um 07:04 Uhr
> Von: "Derek Kwan" <derek.x.kwan at gmail.com>
> An: pd-list at lists.iem.at
> Betreff: [PD] Request - Deleting struct instances, progress?
> I suppose since we're doing this about feature requests, I'd like to ask
> about deleting instances of structs in linked lists =). 
> I've read through the list archive and seen this pop up a few times,
> one of the issues being brought up being stale pointers if I recall
> correctly. Is there any progress on this? Would it be possible to
> just copy over the data from the next node (if it exists) into the
> requested deleted node and dealloc the original next node? And if
> a current [pointer] is empty/stale, the next [pointer] the same, just
> reset to the head as a failsafe? Admittedly, I'm not very familiar with
> the mechanisms behind [pointer]s so I could be talking complete
> nonsense so apologies in advance...
> I suppose that this is a somewhat unrelated question, but what is the
> [scalar] object supposed to do? Is it just a specific instance of a
> struct in the linked list? 
> I'd also echo William's words and say thanks for Pd, Miller =)
> Derek
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