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Question on "Adding Productions when Strict is False"

From: Rumen Kyusakov <kjussakov@gmail.com>
Date: Wed, 24 Oct 2012 11:27:04 +0200
Message-ID: <CAPim+c5RgbLx=_puL4XE-GpJOdEWCFMBxvaWnA3Vp4L18F8f1w@mail.gmail.com>
To: public-exi@w3.org
Dear all,

I have a question regarding encoding of event codes in schema mode
when strict is FALSE.
According to my understanding of
http://www.w3.org/TR/2011/REC-exi-20110310/#addingProductions the
second level productions (the productions with even codes with 2
for the first grammar rule of schema-derived grammars are:

Element-i,0 : EE                                          n.m // Only
if not available already with shorter event code
                   AT(xsi:type) Element-i,0     next n.m
                   AT(xsi:nil) Element-i,0        next n.m
                   AT (*) Element-i,0              next n.m
                   NS Element-i,0                  next n.m // If NS
are preserved
                   SC Fragment                     next n.m // If SC
are preserved
                   SE (*) Element-i,c2            next n.m
                   CH [untyped] Element-i,c2  next n.m
                   ER Element-i,c2                next n.m // If ER
are preserved

However, when looking at the EXIficient implementation:
in the SchemaInformedFirstStartTag class, methods getNumberOf2ndLevelEvents()
and get2ndLevelEventCode(), the code includes one more production with
even code with 2 parts:

Element-i,0 : AT (*) [untyped] Element-i,0 n.m+2)

It is inserted before "NS Element-i,0   next n.m" production and after
the "AT (*) Element-i,0    next n.m"
In the source code this extra production is referred in the comments
as "AT(invalid)."

According to my understanding of the specification this productions
has three parts
event code that is defined by the following fragment from the spec:

For each non-terminal Element i, j , such that 0 ≤ j ≤ content , with
zero or more productions of the following form:

Element i, j :
        AT (qname 0 ) [schema-typed value] NonTerminal 0
        AT (qname 1 ) [schema-typed value] NonTerminal 1
        AT (qname x-1 ) [schema-typed value] NonTerminal x-1
where x represents the number of attributes declared in the schema for
this context, add the following productions:

Element i, j :
        AT (*) Element i, j n.m
        AT (qname 0 ) [untyped value] NonTerminal 0 n.(m+1).0
        AT (qname 1 ) [untyped value] NonTerminal 1 n.(m+1).1
            ⋮     ⋮
        AT (qname x-1 ) [untyped value] NonTerminal x-1 n.(m+1).(x-1)
        AT (*) [untyped value] Element i, j n.(m+1).(x)

where n.m represents the next available event code with length 2.

The last production "AT (*) [untyped value] Element i, j n.(m+1).(x)" has
three parts and not 2.

Some test with OpenEXI showed that the same extra production "AT (*)
[untyped]" with even code with two parts is used as well.

Can someone give me pointers on why we have this extra production?

Best Regards,
Received on Saturday, 27 October 2012 07:32:48 UTC

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