Seemingly-orphan parts

[John Haug]

I think it was left to specific file format specifications built on OPC to determine how to handle things like this.  For example, this is addressed in Part 1:

9.1.4 Unknown Parts
With the exception of relationship parts, all other parts in an Office Open XML document that are not the target
of an implicit or explicit relationship are considered unknown parts. Unknown parts shall be ignored on
document consumption and can, but need not, be discarded on production.

John

From: eb2mmrt at gmail.com [mailto:eb2mmrt at gmail.com] On Behalf Of MURATA Makoto
Sent: Saturday, May 2, 2015 4:05 AM
To: SC34
Subject: Seemingly-orphan parts

Dear colleagues,

Is it ok to embed parts in an OPC package without having
relationships to them?  Such parts may be referenced by the
href attribute of some XML element, for example.  OPC
explicitly allows such references.

              Parts may contain references to other parts in the
              package and to resources outside of the
              package. These references are represented inside
              the referring part in ways that are specific to
              the content type of the part; that is, in
              arbitrary markup or an application-defined
              encoding. This effectively hides the internal and
              external links between parts from consumers that
              do not understand the content types of the parts
              containing such references.

Since such references are invisible from OPC implementations
or even OOXML implementations (when references appear within
application-defined extension elements).  Thus, OPC or OOXML
implementations should never throw away parts, since they
might be used.  But I know that implementations do throw away
seemingly-orphan parts.  We might want to explicitly state
that seemingly-orphan parts should not be thrown away.
Alternatively, we might want to discourage seemingly-orphan
parts and thus ad-hoc references without explicit relationships.

Regards,
Makoto
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mailman.vse.cz/pipermail/sc34wg4/attachments/20150505/a8c1ab84/attachment.html>