private static CoercionFlags?GetCoercion(FunctionMethod overload, ImmutableArray <MRepr> inputs)
{
var coercionFlags = CoercionFlags.None;
for (int i = 0; i < inputs.Length; ++i)
{
MRepr provided = inputs[i];
MRepr expected = overload.Signature.Inputs[i];
if (provided == expected)
{
continue;
}
if (expected.IsAny)
{
coercionFlags |= CoercionFlags.ToAny;
continue;
}
// Check structural class compatibility
if (provided.StructuralClass != expected.StructuralClass)
{
// TODO: Check the subtyping relation of the structural classes
if (expected.StructuralClass == MStructuralClass.Scalar)
{
return(null);
}
coercionFlags |= CoercionFlags.StructuralClassChange;
}
// Check complex attribute compatibility
if (provided.IsComplex != expected.IsComplex)
{
if (provided.IsComplex)
{
return(null); // Complex to real
}
coercionFlags |= CoercionFlags.RealToComplex;
}
// Check class compatibility.
if (provided.Class != expected.Class)
{
if (provided.Class.IsInteger && expected.Class.IsReal)
{
coercionFlags |= CoercionFlags.IntegerToFloat;
}
else
{
return(null);
}
}
}
return(coercionFlags);
}
public FunctionMethod Lookup(string name, ImmutableArray <MRepr> inputs)
{
Contract.Requires(name != null);
var key = new GroupKey(name, inputs.Length);
FunctionMethod bestOverload = null;
// Perform overload resolution based on the required input coercions
List <FunctionMethod> overloads;
if (functions.TryGetValue(key, out overloads))
{
var leastCoercionFlags = CoercionFlags.None;
foreach (var overload in overloads)
{
var overloadCoercionFlags = GetCoercion(overload, inputs);
if (!overloadCoercionFlags.HasValue)
{
continue; // Not admissible
}
if (bestOverload == null || overloadCoercionFlags.Value < leastCoercionFlags)
{
// TODO: assert we don't have multiple overloads with the same minimal admissibility
bestOverload = overload;
leastCoercionFlags = overloadCoercionFlags.Value;
}
}
}
// Make sure we have an admissible overload
if (bestOverload == null)
{
var message = new StringBuilder();
message.Append("No admissible overload for function ")
.Append(name)
.Append(" with input types (");
for (int i = 0; i < inputs.Length; ++i)
{
if (i >= 1)
{
message.Append(", ");
}
message.Append(inputs[i].ToString());
}
message.Append(')');
throw new KeyNotFoundException(message.ToString());
}
return(bestOverload);
}
public void AddFunction(FunctionMethod function)
{
Contract.Requires(function != null);
var key = new GroupKey(function.Name, function.Signature.Inputs.Count);
List <FunctionMethod> overloads;
if (!functions.TryGetValue(key, out overloads))
{
overloads = new List <FunctionMethod>();
functions.Add(key, overloads);
}
overloads.Add(function);
}
public void AddMethod(MethodInfo method)
{
Contract.Requires(method != null);
if (method.IsGenericMethodDefinition)
{
foreach (var instantiation in InstantiateGenericMethod(method))
{
AddMethod(instantiation);
}
return;
}
// TODO: Support variadic arguments
// TODO: Support variadic return parameters
var function = new FunctionMethod(method);
AddFunction(function);
}