Permit me to parse your answer and ask additional questions. I've already
managed to munge the string into the proper format with concat() and
substring(), but this
<xsl:function name="f:to-iso-date" as="xs:date">
<xsl:param name="in" as="my:yyyymmdd-date"/>
<xsl:sequence select="xs:date(replace($in, '(\d{4})(\d{2})(\d{2})',
'$1-$2-$3'))"/>
</xsl:function>
is appealing because of it's perl-ishness (yes, of course perl incorporated
existing concepts from UNIX shell utilities like sed and awk, but I first
encountered them when learning perl), and because the function casts the return
value to an xs:date.
In order to use this approach you suggest that I incorporate an
xsl:import-schema declaration in my stylesheet and use it with either of the
functions.
On the other hand, I'm using the non-schema-aware version of Saxon.
In reviewing the section on xsl:import-schema in "XSLT 2.0 Programmer's
Reference" on page 324 I note that, "This declaration is only available in a
schema-aware processor." So, how then would substituting " ... xs:string in
place of my:yyyymmdd-date ..." solve that issue?
I am puzzled by what appears to me as an inconsistency in the answer which I
must attribute to my weak grasp of the subject. If I cannot use the suggested
approach because my processor is not schema-aware, is there some other native
XSLT 2.0 approach, or am I forced to use some extension function?
--
Charles Knell
cknell(_at_)onebox(_dot_)com - email
-----Original Message-----
From: Michael Kay <mike(_at_)saxonica(_dot_)com>
Sent: Thu, 18 May 2006 08:27:54 +0100
To: <xsl-list(_at_)lists(_dot_)mulberrytech(_dot_)com>
Subject: RE: [xsl] XSLT 2.0/XPath 2.0 Date arithmetic
Given a parameter, let's call it "today" in the form of this
string "20060517", how do I create a variable, let's call it
"tMinus1" such that it represents a day earlier than
"20060517", that would be "20060516". So long as "$today"
isn't the first day of a month, a simple subtraction and
followed by a type cast that I don't grasp would do the trick.
What I'm looking for is guidance on date arithmetic.
You'd be much better off working with the xs:date type, which uses the
format 2006-05-17.
So, two functions to convert between your non-standard dates and standard
xs:date objects:
<xsl:import-schema>
<xs:schema target-namespace="http://my-date";>
<xs:simpleType name="yyyymmdd-date">
<xs:restriction base="xs:string">
<xs:pattern value="[0-9]{4}[0-1][0-9][0-3][0-9]"/>
</
</
</
</
<xsl:function name="f:to-iso-date" as="xs:date">
<xsl:param name="in" as="my:yyyymmdd-date"/>
<xsl:sequence select="xs:date(replace($in, '(\d{4})(\d{2})(\d{2})',
'$1-$2-$3'))"/>
</xsl:function>
<xsl:function name="f:to-yyyymmdd-date" as="my:yyyymmdd-date">
<xsl:param name="in" as="xs:date"/>
<xsl:sequence select="my:yyyymmdd-date(translate(string($in, '-', ''))"/>
</xsl:function>
then:
select="f:to-yyyymmdd-date(f:to-iso-date($input-date) -
xs:dayTimeDuration('PT1D'))"
If you're not schema-aware, then use xs:string in place of my:yyyymmdd-date
- all you lose is type-checking.
Michael Kay
http://www.saxonica.com/
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