"Egon Andersen, Talura" wrote:
>
> Hi,
>
> I came across the following notation:
>
> MyType1 ::= SEQUENCE {
> ...,
> ...}
>
> This seems to be perfectly legal according to X.680 (1997 E) clause 24.1
>
> According to 3.8.29 the 'extension insertion point' is in between the
> two ellipsis.
>
> MyType2 ::= SEQUENCE {
> ...,
> alpha INTEGER,
> ...}
>
> should then be the propper way to extend with a NamedType.
>
> But this does not comply to any of the alternatives in
> ComponentTypeLists.
> All alternatives in ComponentTypeLists requires a RootComponentTypeList,
> which is non-empty.
Good catch! I'll make sure that this will be mended in the 2002 edition of
the ASN.1 standard.
> How do I extend MyType1 according to X.680 (1997 E)?
>
> In the X.680 (1994 E)/Amd.1(1995 E) the notations would have been:
> MyType3 ::= SEQUENCE {...}
> and extended to:
> MyType4 ::= SEQUENCE {..., alpha INTEGER}
Correct. You can use it, for it's not worth having a second extension marker
when the extension root is not splitted in two parts. Anyway 24.1 needs to
be mended.
--
Olivier DUBUISSON (ITU-T ASN.1 Rapporteur)
france telecom R&D
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