[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: Constructor rationale questions



Andre van Tonder <andre@xxxxxxxxxxxxxxxxx> writes:

Andre van Tonder <andre@xxxxxxxxxxxxxxxxx> writes:

> "If the custom field initialization were omitted, it would still be possible to 
> perform custom initialization by writing a separate constructor procedure, which 
> would wrap a record type's actual constructor. 
> [...]
> I have not read the reference implementations in detail, but presumably they 
> construct the syntactic layer on top of the procedural substrate.  Yet the 
> procedural substrate makes no reference to a custom constructor.  Doesn't this 
> contradict the last line above by showing that you can build a layer that allows 
> extensions with access to custom constructors from a layer that doesn't store 
> custom constructors?

Yes, but you misunderstand the sentence in the draft: It's not saying

"If ..., it would still be possible to <something>.  However, we want
to make <something> impossible."

Instead, the sentence is trying to say: "If the construction procedure
was defined outside the DEFINE-TYPE, it wouldn't be available through
the type defined by DEFINE-TYPE, and we couldn't use it, say, through
the PARENT clause."

Would this be a better wording?

-- 
Cheers =8-} Mike
Friede, Völkerverständigung und überhaupt blabla