[xacml] SH01: xs:decimal string representation

Section A.3 Representations says:

  For integers and decimals, XACML SHALL use the conversions
  described in IBM Standard Decimal Arithmetic document at
  the following URL:

    http://www2.hursley.ibm.com/decimal/decarith.html

  This document combines the various standards set forth by
  IEEE and ANSI for string representation of numeric values.

The IBM document defines a numeric string syntax that
allows scientific notation, NaNs, and infinities. The XML
schema document that defines the permissible contents of the
xs:decimal data type does not allow any of these.

I suggest that a note be added after the above passage,
saying:

  Note that although the IBM document allows exponents,
  NaNs, and infinities the XML Schema specification does
  not allow these in an xs:integer and xs:decimal value.
  Therefore, they MUST NOT be used in such values.

Thanks,

Steve Hanna
Sun Microsystems, Inc.