/// <summary>
/// Finds the signature that best matches the arguments
/// </summary>
/// <param name="functionName">The name of the function</param>
/// <param name="argumentTypes">The types of the arguments</param>
/// <param name="signatures">The signatures to match against</param>
/// <returns>Returns the matching signature or throws</returns>
internal static FunctionSignatureWithReturnType MatchSignatureToBuiltInFunction(string functionName, IEdmTypeReference[] argumentTypes, FunctionSignatureWithReturnType[] signatures)
{
DebugUtils.CheckNoExternalCallers();
FunctionSignatureWithReturnType signature;
// Handle the cases where we don't have type information (null literal, open properties) for ANY of the arguments
int argumentCount = argumentTypes.Length;
if (argumentTypes.All(a => a == null) && argumentCount > 0)
{
// we specifically want to find just the first function that matches the number of arguments, we don't care about
// ambiguity here because we're already in an ambiguous case where we don't know what kind of types
// those arguments are.
signature = signatures.FirstOrDefault(candidateFunction => candidateFunction.ArgumentTypes.Count() == argumentCount);
if (signature == null)
{
throw new ODataException(ODataErrorStrings.FunctionCallBinder_CannotFindASuitableOverload(functionName, argumentTypes.Count()));
}
else
{
// in this case we can't assert the return type, we can only assert that a function exists... so
// we need to set the return type to null.
signature = new FunctionSignatureWithReturnType(null, signature.ArgumentTypes);
}
}
else
{
signature = TypePromotionUtils.FindBestFunctionSignature(signatures, argumentTypes);
if (signature == null)
{
throw new ODataException(ODataErrorStrings.MetadataBinder_NoApplicableFunctionFound(
functionName,
BuiltInFunctions.BuildFunctionSignatureListDescription(functionName, signatures)));
}
}
return(signature);
}