///<summary>
/// Call a global user-defined function in the compiled query.
///</summary>
///<remarks>
/// If this is called more than once (to evaluate the same function repeatedly with different arguments,
/// or to evaluate different functions) then the sequence of evaluations uses the same values of global
/// variables including external variables (query parameters); the effect of any changes made to query parameters
/// between calls is undefined.
/// </remarks>
/// <param name="function">
/// The name of the function to be called
/// </param>
/// <param name="arguments">
/// The values of the arguments to be supplied to the function. These
/// must be of the correct type as defined in the function signature (there is no automatic
/// conversion to the required type).
/// </param>
/// <exception cref="ArgumentException">If no function has been defined with the given name and arity
/// or if any of the arguments does not match its required type according to the function
/// signature.</exception>
/// <exception cref="DynamicError">If a dynamic error occurs in evaluating the function.
/// </exception>
public XdmValue CallFunction(QName function, XdmValue[] arguments)
{
JUserFunction fn = exp.getStaticContext().getUserDefinedFunction(
function.Uri, function.LocalName, arguments.Length);
if (fn == null)
{
throw new ArgumentException("No function with name " + function.ClarkName +
" and arity " + arguments.Length + " has been declared in the query");
}
try {
// TODO: use the same controller in other interfaces such as run(), and expose it in a trapdoor API
if (controller == null)
{
controller = exp.newController();
context.initializeController(controller);
controller.defineGlobalParameters();
}
ValueRepresentation[] vr = new ValueRepresentation[arguments.Length];
for (int i = 0; i < arguments.Length; i++)
{
SequenceType type = fn.getParameterDefinitions()[i].getRequiredType();
vr[i] = arguments[i].Unwrap();
if (!type.matches(Value.asValue(vr[i]), controller.getConfiguration()))
{
throw new ArgumentException("Argument " + (i + 1) +
" of function " + function.ClarkName +
" does not match the required type " + type.toString());
}
}
ValueRepresentation result = fn.call(vr, controller);
return(XdmValue.Wrap(result));
} catch (JXPathException e) {
throw new DynamicError(e);
}
}