Re: [xslt] confusing error message "function format-date bound to undefined prefix date"

[Michael Ludwig <mlu as-guides com>]

Viktor Stujber schrieb:
> Greetings. We had some trouble when modifying our presentation layer
> to use (e)xslt date formatting. The problematic code looked like this:
>
> <xsl:value-of select="date:format-date(str:replace($date, ' ', 'T'),
> 'HH:mm:ss | dd. MMMM, yy')"/>
>
> This line worked on its author's test setup, which used an older
> libxslt version. But when deployed on our webserver, it started
> throwing errors:
>
> xmlXPathCompOpEval: function format-date bound to undefined prefix date
> xmlXPathCompiledEval: 1 objects left on the stack.

First, the error message strongly suggests you haven't bound the prefix
"date" to a namespace. As a consequence, the XPath expression cannot be
compiled.

Second, as this extension function isn't supported natively be LibXSLT,
which can be checked by doing `xsltproc --dumpextensions`, you have to
include the EXSLT function supplied by Jeni Tennison in your transform.

http://www.exslt.org/date/functions/format-date/index.html

This has a dependency on "str.padding.function.xsl", which you can
remove when using LibXSLT, as it is implemented natively in this
processor. See the example below.

Michael Ludwig

<xsl:stylesheet version="1.0"
  xmlns:str="http://exslt.org/strings";
  xmlns:date="http://exslt.org/dates-and-times";
  xmlns:xsl="http://www.w3.org/1999/XSL/Transform";>

  <xsl:include href="date.format-date.function.xsl"/>

  <xsl:output method="text"/>

  <xsl:template match="/">
    <xsl:variable name="date" select="'2009-03-23 10:21:00'"/>
    <xsl:variable name="fmt"  select="'HH:mm:ss | dd. MMMM, yy'"/>

    <xsl:value-of select="str:replace( $date, ' ', 'T')"/>
    <xsl:text>&#10;</xsl:text>

    <xsl:value-of select="
      date:format-date( str:replace( $date, ' ', 'T'), $fmt)"/>
    <xsl:text>&#10;</xsl:text>
  </xsl:template>

</xsl:stylesheet>