public async Task <IMember> GetValueFromFunctionTypeAsync(IPythonFunctionType fn, IPythonInstance instance, CallExpression expr, CancellationToken cancellationToken = default)
{
// Determine argument types
var args = new ArgumentSet(fn, instance, expr, this);
args = await args.EvaluateAsync(cancellationToken);
// If order to be able to find matching overload, we need to know
// parameter types and count. This requires function to be analyzed.
// Since we don't know which overload we will need, we have to
// process all known overloads for the function.
foreach (var o in fn.Overloads)
{
await SymbolTable.EvaluateAsync(o.FunctionDefinition, cancellationToken);
}
// Re-declare parameters in the function scope since originally
// their types might not have been known and now argument set
// may contain concrete values.
if (fn.FunctionDefinition != null)
{
using (OpenScope(fn.FunctionDefinition, out _)) {
args.DeclareParametersInScope(this);
}
}
// If instance is not the same as the declaring type, then call
// most probably comes from the derived class which means that
// the original 'self' and 'cls' variables are no longer valid
// and function has to be re-evaluated with new arguments.
var instanceType = instance?.GetPythonType();
if (instanceType == null || fn.DeclaringType == null || fn.IsSpecialized ||
instanceType.IsSpecialized || fn.DeclaringType.IsSpecialized ||
instanceType.Equals(fn.DeclaringType))
{
var t = instance?.Call(fn.Name, args) ?? fn.Call(null, fn.Name, args);
if (!t.IsUnknown())
{
return(t);
}
}
// Try and evaluate with specific arguments but prevent recursion.
return(await TryEvaluateVithArgumentsAsync(fn.FunctionDefinition, args, cancellationToken));
}