/// <summary>
/// Bind this function call token as a built in function
/// </summary>
/// <param name="functionCallToken">the function call token to bidn</param>
/// <param name="state">the current state of the binding algorithm</param>
/// <param name="argumentNodes">list of semantically bound arguments</param>
/// <returns>A function call node bound to this function.</returns>
private static QueryNode BindAsBuiltInFunction(FunctionCallToken functionCallToken, BindingState state, List <QueryNode> argumentNodes)
{
if (functionCallToken.Source != null)
{
// the parent must be null for a built in function.
throw new ODataException(ODataErrorStrings.FunctionCallBinder_BuiltInFunctionMustHaveHaveNullParent(functionCallToken.Name));
}
// There are some functions (IsOf and Cast for example) that don't necessarily need to be bound to a BuiltInFunctionSignature,
// for these, we just Bind them directly to a SingleValueFunctionCallNode
if (IsUnboundFunction(functionCallToken.Name))
{
return(CreateUnboundFunctionNode(functionCallToken, argumentNodes, state));
}
// Do some validation and get potential built-in functions that could match what we saw
FunctionSignatureWithReturnType[] signatures = GetBuiltInFunctionSignatures(functionCallToken.Name);
IEdmTypeReference[] argumentTypes = EnsureArgumentsAreSingleValue(functionCallToken.Name, argumentNodes);
FunctionSignatureWithReturnType signature = MatchSignatureToBuiltInFunction(functionCallToken.Name, argumentTypes, signatures);
if (signature.ReturnType != null)
{
TypePromoteArguments(signature, argumentNodes);
}
IEdmTypeReference returnType = signature.ReturnType;
return(new SingleValueFunctionCallNode(functionCallToken.Name, new ReadOnlyCollection <QueryNode>(argumentNodes), returnType));
}