/// <summary>
/// Infers the types of the given collection of named type arguments from the given collection
/// of parameters.
/// </summary>
/// <param name="typeArgNames">The names of the type parameters.</param>
/// <param name="parameters"></param>
/// <returns></returns>
public static IList <IBoundDecl> Infer(IEnumerable <string> typeParameters,
IUnboundDecl parameterType,
IBoundDecl argType)
{
var inferrer = new TypeArgInferrer(typeParameters);
inferrer.mParamTypes.Push(parameterType);
bool dummy = argType.Accept(inferrer);
inferrer.mParamTypes.Pop();
// if the inference failed (like from a type collision) then fail
if (inferrer.mFailed)
{
return(null);
}
// if any type argument is left unfilled then fail
if (inferrer.mTypeArguments.Contains(null))
{
return(null);
}
return(inferrer.mTypeArguments);
}
public BindingContext BuildContext(BindingContext callingContext,
IUnboundDecl parameterType, IBoundDecl argType,
ref IEnumerable <IBoundDecl> typeArgs, out bool canInferArgs)
{
// try to infer the args if not passed in
IList <IBoundDecl> inferredTypeArgs = TypeArgInferrer.Infer(TypeParameters,
parameterType, argType);
canInferArgs = inferredTypeArgs != null;
if (canInferArgs)
{
typeArgs = inferredTypeArgs;
}
if (typeArgs.IsEmpty())
{
typeArgs = null;
}
// include the open namespaces of the calling context. this was the instantiated
// generic has access to everything that the instantiation call site has access
// to
var searchSpace = new NameSearchSpace(BaseType.SearchSpace, callingContext.SearchSpace);
return(new BindingContext(callingContext.Compiler, searchSpace, TypeParameters, typeArgs));
}
//### bob: this is basically a copy from Struct :(
public Union Instantiate(Compiler compiler, IEnumerable <IBoundDecl> typeArgs)
{
// look for a previously instantiated one
var union = compiler.Types.FindUnion(BaseType.Name, typeArgs);
if (union == null)
{
// instantiate the structure
union = BaseType.Clone(typeArgs);
// add it to the list of known types. this must happen before
// the subsequent binding in case the type is recursive.
compiler.Types.Add(union, typeArgs);
// immediately bind it with the type arguments
BindingContext context = new BindingContext(compiler, union.SearchSpace, TypeParameters, typeArgs);
TypeBinder.Bind(context, union);
// figure out which of the cases can infer type arguments. this
// needs to be done now while we still know the type parameters
// and the unbound uses of them in the cases.
for (int i = 0; i < union.Cases.Count; i++)
{
var inferredTypeArgs = TypeArgInferrer.Infer(TypeParameters,
BaseType.Cases[i].ValueType.Unbound,
union.Cases[i].ValueType.Bound);
union.Cases[i].HasInferrableTypeArguments = inferredTypeArgs != null;
}
}
return(union);
}
