[Oberon] Assignment to value parameters of pointer or procedure type

[Florian Negele]

It really depends on the version of Oberon at hand:

* The original Oberon report states in Section 6 that "Such association 
may be with unstructured (basic) types, or it may be with structured 
types [...]. There are two different structures, namely arrays and 
records [...]."

It follows that basic types are synonymous with unstructured types which 
are thus all types except arrays and records. This is consistent with 
the aforementioned non-exclusive wording of the first sentence in 
Section 6.1 which reads "The following basic types are denoted by 
predeclared identifiers."

* Oberon-07 keeps the same wording in Section 6.1 but unfortunately does 
no longer contain the clarifying equality of unstructured and basic 
types. This leaves room for interpretation and confusion.

* Oberon-2 on the other hand also drops that equality but makes it 
absolutely clear in the first sentence of Section 6.1 that "The basic 
types are denoted by predeclared identifiers." This is also consistent 
with the overall structure of Section 6 which distinguishes between 
basic, array, record, pointer, and procedure types.

Procedure and pointer types are unstructured and thus basic in the 
original Oberon and maybe in Oberon-07, but clearly not in Oberon-2.


On 09/02/2025 15:59, August Karlstrom wrote:
> On 2025-02-09 15:00, Diego Sardina wrote:
>> Pointers and procedure variables are of basic types.
>>
>> In an old email Wirth confirmed that the terms basic and scalar types 
>> were synonyms.
> 
> Thanks for the clarification. Actually, the first sentence in section 
> 6.1. says "The following basic types are denoted by predeclared 
> identifiers." The wording indicates that there are other basic types 
> even if it doesn't explicitly say that the additional ones are pointer 
> and procedure types. Previously I was under the impression that the 
> basic types were exactly the ones mentioned in section 6.1.
> 
> https://miasap.se/obnc/oberon-report.html#sec6.1
> 
> 
> /August
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