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[Bug 1699] New: [FS] algebra of sequence concatenation is not complete

From: <bugzilla@wiggum.w3.org>
Date: Sun, 17 Jul 2005 23:09:28 +0000
To: public-qt-comments@w3.org
Cc:
Message-Id: <E1DuIGG-000648-L4@wiggum.w3.org>

http://www.w3.org/Bugs/Public/show_bug.cgi?id=1699

           Summary: [FS] algebra of sequence concatenation is not complete
           Product: XPath / XQuery / XSLT
           Version: Last Call drafts
          Platform: PC
        OS/Version: Windows 2000
            Status: NEW
          Severity: normal
          Priority: P2
         Component: Formal Semantics
        AssignedTo: simeon@us.ibm.com
        ReportedBy: fred.zemke@oracle.com
         QAContact: public-qt-comments@w3.org


4.3.1 Constructing sequences
The rule under dynamic evaluation presumes that the algebra of
sequences under concatenation is known, but the purpose of the
Formal Semantics is to explain semantics, not presume semantics.
I think you need the following rule in addition to the stated one:

dynEnv |- Value = (A1, ... An), (B1, ... Bm)
---------------------------------------------
dynEnv |- Value = (A1, ..., An, B1, ... Bm)

Or perhaps it can be done by rewording your existing rule as
follows:

dynEnv |- Expr1 => (A1, ... An)
dynEnv |- Expr2 => (B1, ... Bm)
-------------------------------
dynEnv |- Expr1, Expr2 => (A1, ..., An, B1, ..., Bm)

This includes as a special case the following:

dynEnv |- Value1 = ()
dynEnv |- Value2 = (B1, ... Bm)
-------------------------------
dynEnv |- Value1, Value2 = Value2

dynEnv |- Value1 = (A1, ... An)
dynEnv |- value2 = ()
-------------------------------
dynEnv |- Value1, Value2 = Value2
Received on Sunday, 17 July 2005 23:27:41 UTC

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