Some years ago a good friend of mine showed me a folder of patches named "pd-msg", and we had fun with it.
When trying to find it back, a quick internet search led me there : https://puredata.info/community/pdwiki/PdInternalMessages
It seems it's from the pd-extended days, but doesn't mention [namecanvas]
Apart from that, it still looks like a good reference for patcher scripting ...

Le 10/04/19 à 12:00, pd-list-request@lists.iem.at a écrit :

Date: Wed, 10 Apr 2019 09:46:46 +0200
From: IOhannes m zmoelnig <zmoelnig@iem.at>
To: pd-list@lists.iem.at
Subject: Re: [PD] patcher scripting using $0 ?
Message-ID: <d2dbb8a3-c27f-a6eb-b699-446858230035@iem.at>
Content-Type: text/plain; charset="utf-8"

On 10.04.19 02:35, Joseph Larralde wrote:

Looks like I still need to catch up with latest pd improvements.

so much to read, so little time :-)

Indeed :)
I suppose digging in the list archive would have given me the answer ...
Please excuse my laziness.

i did a quick check, and Pd-0.25 contained a helppatch for [namecanvas],
which demonstrates that it basically worked the same as it still does.
(i don't remember whether you could use $0 back then; if so, then only
at the beginning of a symbol, e.g. "$0-foo" but not "foo.$0")

So it was just under my nose all that time (sigh)

fgmadrt
IOhannes

Thanks again,
Joseph