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Bug 1645 - [FS] tightening the description of the Normalization phase
Summary: [FS] tightening the description of the Normalization phase
Status: CLOSED FIXED
Alias: None
Product: XPath / XQuery / XSLT
Classification: Unclassified
Component: Formal Semantics 1.0 (show other bugs)
Version: Last Call drafts
Hardware: PC Windows 2000
: P2 minor
Target Milestone: ---
Assignee: Jerome Simeon
QA Contact: Mailing list for public feedback on specs from XSL and XML Query WGs
URL:
Whiteboard:
Keywords:
Depends on:
Blocks:
 
Reported: 2005-07-15 22:19 UTC by Fred Zemke
Modified: 2005-09-29 14:35 UTC (History)
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Description Fred Zemke 2005-07-15 22:19:15 UTC
3.2.1 Processing model
Step 3, "Normalization" contains statements that are contradicted
in Section 3.5.3 "SequenceType Syntax", to wit:

1. Section 3.2.1 contains "... the [XPath/XQuery] Core language...is 
a subset of the XQuery grammar" but 3.5.3 points out that 
the type system in the Core grammar is not a subset of 
XQuery grammar.  The correction would be to reword 3.2.1 to say
that Core is mostly a subset of XQuery, except that the type 
system in Core is richer than XQuery's.

2. Section 3.2.1 portrays Normalization as a phase that can be
performed in entirety after phase 2, "static context processing",
and before phase 3, "static type analysis".  Section 3.5.3 says
that normalization of sequence types can occur "whenever a
dynamic or static rule requires it".  Presumably the reference
to "static rule" is a reference to phase 4 "static type analysis"
in section 3.2.1.  This could be clarified in both sections.
Comment 1 Michael Dyck 2005-07-15 22:50:25 UTC
(In reply to comment #0)
> 3.5.3 points out that 
> the type system in the Core grammar is not a subset of 
> XQuery grammar.  The correction would be to reword 3.2.1 to say
> that Core is mostly a subset of XQuery, except that the type 
> system in Core is richer than XQuery's.

As far as I can tell, the SequenceType grammar is the same for XQuery and Core.
It's true that "the type system" is richer than can be expressed by
SequenceType, but that is outside the XQuery and Core grammars. ('Type' is a
Formal symbol.)
Comment 2 Fred Zemke 2005-07-19 22:27:27 UTC
Thanks for the response.  I see your point, SequenceType is part of Core,
but Type is not.  I think the following things can be done to ameliorate this 
confusion for other readers:

1. Change the spelling of Type to FormalType.  Otherwise it is way too
confusing distinguishing "Type" from "type", the latter being the 
ordinary English word which is part of our metalanguage.  I imagine this
confusion must occur repeatedly in spoken English in the working group,
and even if the working group can manage it, what about the public at large?

2. Use some other term than normalization for the conversion of 
SequenceType to FormalType.  That way you can be 100% consistent that
"normalization" refers to phase 3 of static analysis.  For example, you
can provide a judgment "FormalType is formal type for SequenceType"
with FormalType and SequenceType italicized and the rest in bold.
The inference rules for this judgment are as follows:

statEnv |- FormalType is formal type for SequenceType
------------------------------------------------------
statEnv |- FormalType OccurrenceIndicator is formal type for 
           SequenceType OccurrenceIndicator

- (no premise)
--------------
statEnv |- empty is formal type for void()

- (no premise)
--------------
|- statEnv |- AtomicType is formal type for AtomicType

and so forth, converting all the mapping rules of 3.5.4 to inferences.
Comment 3 Paul Cotton 2005-07-20 00:25:35 UTC
>1. Change the spelling of Type to FormalType. 

Although the WGs can see some merit in this change, we have decided to not 
make this change at this time since the term "Type" is used so many times in 
the document.

>2. Use some other term than normalization for the conversion of 
SequenceType to FormalType.

The WGs have assigned this item to the Editors and will let them decide if 
they will adopt your proposed change.  The Editors were optimistic that they 
will be able to adopt your change.

In addition we have changed the Severity of this comment to Minor to indicate 
the two parts are being treated editorially.

Please let us know if you are not satisifed with this response.

Paul Cotton
On behalf of the XML Query and XSL WGs
Comment 4 Paul Cotton 2005-07-20 00:35:25 UTC
The WGs decided to keep the Note and to change the text "the static typing 
behaviour of" to "static type of".

Please let know if you are not satisfied with this response.

Paul Cotton
On behalf of the XML Query and XSL WGs