SP 2010 - Search Core Results Default XSL Params

Question

I was wondering, where I can find a list of the default xsl params available with the search core result webpart? When we use the default xsl stylesheet of the webpart, default params are defined at the beginning of the file like this:

<xsl:stylesheet version="1.0"
        xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
        xmlns:srwrt="http://schemas.microsoft.com/WebParts/v3/searchresults/runtime"
        xmlns:ddwrt="http://schemas.microsoft.com/WebParts/v2/DataView/runtime">
      <xsl:output method="xml" indent="no"/>
      <xsl:param name="Keyword" />
      <xsl:param name="ResultsBy" />
      <xsl:param name="ViewByUrl" />
      <xsl:param name="ShowDropDown" />
      <xsl:param name="ViewByValue" />
      <xsl:param name="SortBy" />
      <xsl:param name="SortOptions" />
      <xsl:param name="Relevancy" />
      <xsl:param name="ModifiedDate" />
      <xsl:param name="DropDownOption" />
      <xsl:param name="Multiply" />
      <xsl:param name="PictureTaken" />
      <xsl:param name="IsNoKeyword" />
      <xsl:param name="IsFixedQuery" />
      <xsl:param name="ShowActionLinks" />
      <xsl:param name="MoreResultsText" />

etc.

I will not put the entire list here. So my question is, by default, is the list of params in the default xsl is complete or are there hidden params? And more, where those params come from? Parameter Bindings (the parameter bindings property of the searchcoreresults wp seems empty by default)?

Answer 1

XSL transformations in SharePoint work following way:

1. XSLT webpart initializes XSL transformation ("XSLT webpart" can be XsltListViewWebPart, DataFormWebPart, CoreResultsWebPart, etc. - they all work the same way).
2. During the initialization process, a list of parameters and their values is passed to some XSLT processor. The parameters list is formed by the webpart from its properties, from current context, etc. In SharePoint, all the parameters generally could be divided into two main categories: ParameterBindings (user) and Global parameters (internal).
3. XSL transformation runs, executing the provided XSLT code
4. XSLT code grabs needed parameters by their name, using <xsl:param> tag.
5. Parameters referenced and used in the XSLT code, in XPath expressions

I hope the process is much more clear for you now.

So the answer to your question is possibly yes: there could be some hidden internal parameters, which aren't referenced in XSLT code. Only Reflector can tell precisely.