[XML-DEV Mailing List Archive Home] [By Thread] [By Date] [Recent Entries] [Reply To This Message] Re: XML encoding ASN.1 (was Re: Another Question)
Olivier, All, > > a) use the tags as element names ("A17" for [APPLICATION 17]), > > use fixed attributes for identifiers and data type names. > > Tags are historical "residues" in ASN.1. They are only used by the > BER encoding rules. > It is now recommended to add the "AUTOMATIC TAGS" clause in the > module headers and to not take core of the tags any more. Even when AUTOMATIC TAGS is used, each element has a tag. And there seems to be an argument for tags, as can be seen by the wide selection of file formats using some sort of tagging, to be extensible (e.g. MPEG). > > b) use the identifiers as element names, use fixed attributes for tags > > and data type names. > > What's the need to keep the tags and type names? It seems to me that > this verbosity is useless. In the normal case, no verbosity is involved, as fixed attributes aren't transmitted in the document instances. > Do you make the assumption that both sides (i.e., the encoder and the > decoder) are generated from the same ASN.1 module? Yes, but I want to be prepared for extensions. That's the main reason you cannot drop the tag, as that would prohibit round-tripping BER- >XMLencoding->BER. The original sender may use a special tag value to insert an element into a SEQUENCE. You must keep this tag value in the XML encoding for the sahe of re-producing a BER encoded version. Regards, Peter Jacobi *************************************************************************** This is xml-dev, the mailing list for XML developers. To unsubscribe, mailto:majordomo@x...&BODY=unsubscribe%20xml-dev List archives are available at http://xml.org/archives/xml-dev/ ***************************************************************************
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