private void InferIndexer(IndexerExpression ie, TypeInferenceCache cache)
{
InferTypes(ie.Target, cache);
var typeofTarget = cache[ie.Target];
if (typeofTarget is ClrType)
{
var preview = cache.Clone();
ie.Operands.ForEach(operand => InferTypes(operand, preview));
var types = ie.Operands.Select(operand => preview[operand]);
if (types.Any(type => type is Variant))
{
cache.Add(ie, new Variant());
cache.Upgrade(preview);
}
else
{
var alts = typeofTarget.LookupIndexers();
if (alts == null)
{
throw new NoSuchIndexerException(Root, ie, typeofTarget);
}
InferMethodGroup(alts, ie, cache);
}
}
else if (typeofTarget is Variant)
{
cache.Add(ie, new Variant());
}
else
{
throw new NoSuchIndexerException(Root, ie, typeofTarget);
}
}
private void InferOperator(OperatorExpression oe, TypeInferenceCache cache)
{
var preview = cache.Clone();
oe.Operands.ForEach(operand => InferTypes(operand, preview));
var types = oe.Operands.Select(operand => preview[operand]);
if (types.Any(type => type is Variant))
{
cache.Add(oe, new Variant());
cache.Upgrade(preview);
}
else
{
var alts = oe.Type.LookupOperators(types.ToArray());
// logical not can also be used to express ones complement
// since they both correspond to a single LINQ expression type
if (oe.Type == OperatorType.LogicalNot)
{
var addendum = OperatorType.OnesComplement.LookupOperators(types.ToArray());
if (addendum != null)
{
var original = alts == null ? new MethodInfo[0] : alts.Alts;
alts = new MethodGroup(original.Concat(addendum.Alts), oe.Type.GetOpCode());
}
}
if (alts == null)
{
throw new NoSuchOperatorException(Root, oe, types);
}
InferMethodGroup(alts, oe, cache);
}
}
private void InferInvoke(InvokeExpression ie, TypeInferenceCache cache)
{
InferTypes(ie.Target, cache);
var typeofTarget = cache[ie.Target];
if (typeofTarget is ClrType)
{
var preview = cache.Clone();
ie.Args.ForEach(arg => InferTypes(arg, preview));
var types = ie.Args.Select(arg => preview[arg]);
if (types.Any(type => type is Variant))
{
cache.Add(ie, new Variant());
cache.Upgrade(preview);
}
else
{
var clrType = ((ClrType)typeofTarget).Type;
if (clrType.IsDelegate())
{
var sig = clrType.GetFunctionSignature();
InferMethodGroup(new MethodGroup(sig.AsArray(), clrType.Name), ie, cache);
}
else
{
throw new CannotBeInvokedException(Root, ie, typeofTarget);
}
}
}
else if (typeofTarget is MethodGroup)
{
InferMethodGroup((MethodGroup)typeofTarget, ie, cache);
}
else if (typeofTarget is Variant)
{
cache.Add(ie, new Variant());
}
else
{
throw new CannotBeInvokedException(Root, ie, typeofTarget);
}
}