Meanwhile I implemented a little viewer (https://github.com/rochus-keller/Cedar/ ) and started to study the source code, but was very surprised that there doesn't seem to be any object orientation. I had a look at Lampson's Cedar language description some years ago and had the impression that it included OO support, but this was apparently not implemented. I'm particularly interested because Wirth created Oberon after his second stay at PARC where he was exposed to the Cedar language and environment, and Oberon has inheritance (and there are quite many similarities of his Oberon System UI with the Cedar UI).

The Cedar language version manifested in the now published source files (including the Solaris version by 1993) seems to be rather Mesa plus garbage collected structures implicitly "interiting" from ANY for late binding, but no general inheritance and apparently also no polymorphism.

Do you have some inside information about this?

The CD includes a subdirectory called "ppcr/v1.13" with the note "We weren't able to include the source for ppcr with this CDROM, but you will find the header files here describing its interface."

In the paper "Experiences Creating a Portable Cedar" (1989) by Atkinson et al. the PCR Runtime System is described.

Do you happen to know whether this code is included in the now published archive somewhere. Or is it available somewhere else?

Great, thanks for the hint. Does someone know whether there is an easier way to download a directory tree than visiting one file after the other?