hello

i have a template that takes in 5 parameters. i am calling this template twice: by passing all 5 parameters in first call and for the next time i pass only 3 parameters (and my requirement is just to pass 3 parameters when i call for second time). when i run this xsl error is not thrown. since my requirement is satisfied i am still following the same way. will there be any potential problem in this logic under any circumstances.

If you specify a parameter for a template to have a select attribute then that acts as its default value if you don't pass it in when calling the template. e.g.:

<xsl:template name="test">
  <xsl:param name="value" select="10"/>
  <xsl:value-of select="$value"/>
</xsl:template>

<xsl:call-template name="test">
  <xsl:with-param name="value" select="20"/>

</xsl:call-template>

<xsl:call-template name="test">

</xsl:call-template>

/- Sam Judson : Wrox Technical Editor -/

Currently i am not initializing the parameter in the template. i would like to know if initialization is required? whether a default value (say an empty string) will be assigned automatically if i am not initializing the parameter?

You can call a template passing in parameters that aren't defined without problems. For example the following is valid for the above template:

<xsl:call-template name="test">
  <xsl:with-param name="frogs" select="'Supercalifragilisticexpialidocious'"/>
</xsl:call-template>

/- Sam Judson : Wrox Technical Editor -/

let me confirm my understanding..

<xsl:template name="test">
<xsl:param name="value"/>

<xsl:value-of select="$value"/>
</xsl:template>

<xsl:call-template name="test">
<xsl:with-param name="value" select="20"/>

</xsl:call-template>

<xsl:call-template name="test">

</xsl:call-template>

so this should work under all circumstances. right?

I'm fairly sure that's allowed, the second call just returns nothing.

/- Sam Judson : Wrox Technical Editor -/

In XSLT 1.0, parameters declared using xsl:param are always optional. The default value is provided by the select attribute; if there is no select attribute, the default value is a zero-length string.

In XSLT 2.0, parameters are optional provided you don't set required="yes". The rules for the default value take into account whether or not you specified the parameter type in an "as" attribute.

Michael Kay
http://www.saxonica.com/
Author, XSLT Programmer's Reference and XPath 2.0 Programmer's Reference