Beside the parameters explicitly passed to a query, there is also a pre-defined parameter ‘$context’ containing various data about the user and the client that is executing the query.

‘$context’ contains an XML fragment like this:

  <lc:LoginContext 

    xmlns:lc="http://www.teradp.com/schemas/GN4/1/LoginContext.xsd" 

    UserId="obj1705" 

    UserName="teradp\mimo"

    HomeFolderId="1431"

    HomeFolderName="mimo" 

    HomeFolderPath="/system/users/mimo">

    <Pars>

      <add key="..." value=="..."/>

      ...

    </Pars>

  </lc:LoginContext>

  <oc:OperationContext 

    xmlns:oc="http://www.teradp.com/schemas/GN4/1/OperationContext.xsd" 

    UtcNow="2012-08-22T15:43:02.002Z" 

    Now="2012-08-22T10:43:02.002"/>

Use this information to write queries based on the current user or on the execution date-time.  For example

gn4:story[gn4:creatorRef/@idref=$context/lc:LoginContext/@UserId]

returns all stories created by the current user, whereas

gn4:task[@dueDate < $context/oc:OperationContext/@UtcNow]

returns all tasks that have a due-date in the past.  

gn4:variantType[@name=$context/lc:LoginContext/lc:Pars/lc:add[@key='archiveVariantName']/@value]

returns the variant type specified by the archiveVariantName parameter of the current user.

Note how ‘$context’ in GNQuery has the same structure of the ‘$context’ parameter available in XSL transformation, but it contains less information.