public override DynamicMetaObject FallbackInvoke(DynamicMetaObject target, DynamicMetaObject[] args, DynamicMetaObject errorSuggestion)
{
if (!target.HasValue || args.Any(a => !a.HasValue))
{
return(Defer(target, args));
}
var restrictions = RuntimeHelpers.MergeTypeRestrictions(target);
if (!target.LimitType.IsSubclassOf(typeof(Delegate)))
{
return(new DynamicMetaObject(MetamethodFallbacks.Call(context, target, args), restrictions));
}
restrictions = restrictions.Merge(
RuntimeHelpers.MergeTypeRestrictions(args).Merge(
RuntimeHelpers.MergeInstanceRestrictions(target)));
List <Expr> sideEffects;
Expr failExpr;
var function = (Delegate)target.Value;
var methodInfo = function.Method;
var mappedArgs = MapArguments(args, methodInfo, ref restrictions, out sideEffects, out failExpr);
if (failExpr != null)
{
return(new DynamicMetaObject(Expr.Block(failExpr, Expr.Default(typeof(object))), restrictions));
}
var invokeExpr = InvokeExpression(target, mappedArgs, methodInfo);
// Execute overflowing arguments for side effects
Expr expr;
if (sideEffects.Count == 0)
{
expr = invokeExpr;
}
else
{
var tempVar = Expr.Variable(typeof(object));
var assign = Expr.Assign(tempVar, invokeExpr);
sideEffects.Insert(0, assign);
sideEffects.Add(tempVar);
expr = Expr.Block(new[] { tempVar }, sideEffects);
}
return(new DynamicMetaObject(expr, restrictions));
}
void ExpandLastArg(List <Argument> arguments, DynamicMetaObject[] args, ref BindingRestrictions restrictions)
{
if (args.Length == 0)
{
return;
}
var lastArg = args.Last();
if (lastArg.LimitType != typeof(Varargs))
{
return;
}
// TODO: Use custom restriction (checks length and types) and add arguments by indexing into Varargs value
restrictions = restrictions.Merge(RuntimeHelpers.MergeInstanceRestrictions(lastArg));
var varargs = (Varargs)lastArg.Value;
arguments.RemoveAt(arguments.Count - 1);
arguments.AddRange(varargs.Select(value => new Argument(Expr.Constant(value), value.GetType())));
}