Hi

There is a problematic area in Part 2.  Some of the related questions =
are:

- Is ".5" a valid lexical representation for xsd:decimal?

- Is "" a valid lexical representation for xsd:decimal?

- Is "" a valid lexical representation for xsd:integer?

- Is "0" or "" the canonical lexical representation of the integer value =
0?


Part 2 says:

--------------------------------
decimal has a lexical representation consisting of a finite-length =
sequence
of decimal digits (#x30-#x39) separated by a period as a decimal =
indicator.
An optional leading sign is allowed. If the sign is omitted, "+" is =
assumed.
Leading and trailing zeroes are optional. If the fractional part is =
zero,
the period and following zero(es) can be omitted. For example: -1.23,
12678967.543233, +100000.00, 210.
--------------------------------

There are three problematic terms in this paragraph:  "finite-length
sequence", "separated", and "leading zeros".  I am trying to understand =
what
these terms mean by looking in other parts of the document, because they =
are
all ambiguous.

"Finite-length sequence" is used in many other places for the length of:
lists, strings, binary octets of hexBinary, binary octets of baseBinary,
etc.  Obviously, lists, strings, and binary octets must be allowed to =
have a
zero length.  Therefore, at least in these cases (and possibly in all
cases), "finite-length" includes zero-length.   This is supported by the =
use
of the phrase "finite, non-zero-length" for NMTOKENS, IDREFS, and =
ENTITIES,
and by the addition of "(possibly empty)" after "finite-length" in the
definition of list.

So if "finite-length sequence of digits" in xsd:decimal includes zero
digits, then all of the following are valid lexical representations for =
this
type:  "", "+", ".", "3.", ".3".

This has several other implications:

-- "" is a valid lexical representation of the integer value 0

-- "" and "E" are valid lexical representations of the float value 0

Is all of the above intended?  Is this the common understanding?  If =
not,
there is a defect in the specification of the lexical representation of
xsd:decimal and xsd:integer (it should not say "finite-length").

Actually, I doubt that the above was intended.  One of the reasons is =
that
none of the examples in Part 2 shows a decimal number with an empty =
integer
part, or an "empty" integer, but a stronger reason comes from the =
definition
of the canonical lex rep of xsd:integer.  While the definition of the
canonical lex rep of xsd:decimal requires the presence of at least one =
digit
in the integer part, the definition of the canonical lex rep of =
xsd:integer
does not include the same requirement -- it says that leading zeros are
prohibited, full stop.  Is the single "0" in the representation of the
integer value 0 a "leading zero" or not?  Depending on the answer, the
canonical lex rep of the integer value 0 will be either "" or "0".  =
Which is
it?

If the latter is intended, then "fixed-length sequence" for xsd:integer
apparently does not include a zero length, and "leading zeros" =
apparently
does not include the single zero digit representing the integer value =
zero.
But if the former is intended (and so the canonical lex rep of the =
integer 0
is ""), then I wonder why "0.x" (rather than ".x") was chosen as the
canonical lex rep of decimals with a null integer part.

Should "finite-length sequence of digits" have been in both cases =
"finite,
but non-zero-length, sequence of digits"?

Also, should "separated be a period" have been "with a period optionally
inserted at any point in the sequence of digits"?

Or perhaps "with a period optionally inserted at any point in the =
sequence
of digits except before the first digit and after the last digit"?  (or
equivalently "between any two digits"?)

Or perhaps "with a period optionally inserted at any point in the =
sequence
of digits except after the last digit"?

I think the first big question is, What was intended?  And the second =
is, Is
there anything to be mended in the text, and how?

Alessandro Triglia
OSS Nokalva