> I think that my claim that Mesa's GUI was inspired by Smalltalk
That was not my topic.
I was (obviously) talking about the influence of Smalltalk to Oberon, and only that.
And don't forget that the Smalltalk 76 and 80 GUI (and language) we know today was Ingalls' work, not Kay's.
> Wirth didn't know Kay well enough to recognize him
The popularity and influence of Kay is generally overstated. And not to forget that he received the Turing award much later, and what he published was not really the kind of topics Wirth was interested in. At least we have access to all relevant documents today and can check ourselves instead of taking the many tales at face value.
I think the main objective of both the Lilith workstation and the Oberon language were to be practical tools for the kind of graphical user interfaces Kay proposed in his dissertation in 01969 and dedicated much of his PARC research group's effort to advancing. As explained above, Kay's influence is generally acknowledged to be the reason that the PARC's Xerox Alto was capable of running such graphical user interfaces at all.
Oberon's procedure-typed fields came from Modula-2†, and I believe that specifically the reason that Modula-2 reintroduced the procedure (function pointer) types that Modula‡ had removed from Pascal was to support the kind of GUI programming that Wirth had been exposed to during his PARC sabbatical in the Mesa group. However, all I have to support that belief is the chronology, the fact that Oberon does in fact use them for that (and, as far as I've seen, only for that), and some vague memories of reading Project Oberon last millennium.
Pascal procedure types could only be passed as subroutine parameters, which enables the use of nested subroutines as closures without risking runtime errors or requiring garbage collection, because the referenced procedure cannot be called after its lexically-enclosing parent has returned. Modula-2 procedure types do not have this restriction, so they can be stored in records; instead, they have the restriction that, like C function pointers, they cannot refer to nested subroutines.
So I think that Smalltalk's (and Kay's) influence on Oberon was very strong indeed, but mediated through influence on the Mesa group. Certainly Kay's flamboyant and dynamically-typed style, emphasizing recovering from errors rather than preventing them, was not to Wirth's liking.
If I'm interpreting you correctly, you're saying that my original disagreement was mostly with my misunderstanding of what you meant, and the only thing we actually disagree on is how likely it was that Wirth knew Alan Kay personally, which neither of us is very sure about?
That was not my topic.
I was (obviously) talking about the influence of Smalltalk to Oberon, and only that.
And don't forget that the Smalltalk 76 and 80 GUI (and language) we know today was Ingalls' work, not Kay's.
> Wirth didn't know Kay well enough to recognize him
The popularity and influence of Kay is generally overstated. And not to forget that he received the Turing award much later, and what he published was not really the kind of topics Wirth was interested in. At least we have access to all relevant documents today and can check ourselves instead of taking the many tales at face value.