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Re: CBOR and a tag for "critical"

2013-08-15 15:44:42
In fact I answered your question precisely when I mentioned "contained" data items (i.e., contained in the critical one). So I may be wrong but at least I'm consistent...

I think the concept of criticality is powerful, even if in the past we messed it up.

Thanks,
        Yaron

On 2013-08-15 23:35, Paul Hoffman wrote:
On Aug 15, 2013, at 1:19 PM, Yaron Sheffer 
<yaronf(_dot_)ietf(_at_)gmail(_dot_)com> wrote:

I am quite sure that I fully understand the semantics of "critical" (probably 
erroneously), so I'm not the right person to clarify the various meanings of the word. I 
would appreciate a proposal.

Just for the record, my "critical" means: the reader must be able to process 
the data item according to its specification, not just syntactically but also 
semantically, and must fail otherwise. There may still be contained non-critical data 
items that are NOT understood by the reader.

And what you say should happen if a decoder saw the One True Critical tag before an array 
item, and then the decoder soon thereafter finds a tag it does not know about? The 
"critical" tag was on the array, not on the unknown item.

And so on. We've been there, and we haven't done that so well.

Sec. 2.4 consistently mentions "tag" in the singular. For example, the first sentence 
could be "a data item can optionally be preceded by one or more tags" - but it isn't.

A tag is also a data item. A tag refers to the next data item, even if that 
next data item is also a tag. We'll try to clarify this in the -06.

--Paul Hoffman


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