Astrobe Forum

My conclusion is that the EBNF in the Appendix is correct. The wrong semicolon was originally removed in Section 11 and has not been restored yet - otherwise the example in Section 11 would be incorrect. Yes, you are correct. I never noticed the previous error with the extra semicolon in section 11...

As of 2016-05-08 the semicolon after the import list has also been dropped.

1. The real number scale factor "D" is deleted in the grammar in the appendix. Now it's consistent with the syntax in section 3 where only "E" is valid. 2. There is no semicolon after a module identifier. (Currently the grammar in the appendix is not updated). https://www.inf.ethz.ch/personal/wirth/...

What I mean is: Can a variable of type ARRAY n OF T or ARRAY OF T be assigned to a variable of type ARRAY OF T? No. But why can open array be the source of an assignment then? I can't see the reason for allowing open arrays to be the source of an assignment but not the target (of a variable paramet...

Can an open array be the target of an assignment? From the Report: "The type of the expression must be the same as that of the designator" and "Strings can be assigned to any array of characters..." What I mean is: Can a variable of type ARRAY n OF T or ARRAY OF T be assigned to a variable of type ...

In the latest revision "an open array may be assigned to an array of equal base type" but what about the other way around: Can an open array be the target of an assignment? After all, when a formal parameter is an open array a corresponding actual parameter can be an array of any length.

Isn't REAL a predeclared type so that REAL = INTEGER is a redeclaration? It's a predefined type e.g. like ABS . It is not a reserved word like BEGIN . e.g. in earlier versions of Oberon-07 you could have written: PROCEDURE REAL(i: INTEGER); BEGIN END REAL; As far as I understand the above declarati...

The restriction to only allow structured types was introduced in Oberon-07: TypeDeclaration = identdef "=" StrucType. StrucType = ArrayType | RecordType | PointerType | ProcedureType. type = qualident | StrucType. Ah, of course. It's evident from the grammar. My bad. Allowing only structured types ...

As I understand it, the decision between "null-terminated if needed" and "always null-terminated" character arrays is a trade off between declaration interpretation complexity and algorithm complexity. Let's consider the declaration name: ARRAY 32 OF CHAR With the "null-terminated if needed" approac...

qualident can be a basic type. There is an example of this use in the FileDir module in Project Oberon 2013 If my memory serves me correctly, I have read somewhere a text by Niklaus Wirth where he says that the right hand side of a type declaration must be a structured type. My "default" understand...