/**
* @param path path to first element
* @param pathTo path to second element
* @return environment in which the generic parameters in the path to the first element are bound
* to those in the path to the second element, or null type on error
*/
public static ResolvedName mapGenericParameters(
final Deque<? extends INamedElement> path, final Deque<? extends INamedElement> pathTo) {
// Construct an environment in which the current function's generic parameters
// are bound to those of the eventual override.
final Deque<List<? extends ResolvedName>> tableau =
new LinkedList<>(ResolvedName.fromNamedElement(path.getLast()).tableau());
final Iterator<? extends INamedElement> pathIt = path.descendingIterator();
while (pathIt.hasNext()) {
pathIt.next();
tableau.removeLast();
}
CachedIterator<? extends INamedElement> itPathTo = null;
CachedIterator<? extends IGenericParameter> itGPTo = null;
boolean end = false;
{
// Initialise iterators into direct override's generic parameters.
boolean foundValid = false;
itPathTo = Iterators.cached(pathTo.iterator());
while (!foundValid && itPathTo.hasItem()) {
itGPTo = Iterators.cached(itPathTo.item().genericParameters().iterator());
while (!foundValid && itGPTo.hasItem()) {
foundValid = true;
if (!foundValid) itGPTo.next();
}
if (!foundValid) itPathTo.next();
}
if (!foundValid) end = true;
}
for (final INamedElement elt : path) {
final List<ResolvedName> row = new ArrayList<>();
for (@SuppressWarnings("unused")
final IGenericParameter genericParameter : elt.genericParameters()) {
if (end) return null;
row.add(ResolvedName.fromNamedElement(itGPTo.item()));
{
// Increment iterators into direct override's generic parameters.
boolean init = true;
boolean foundValid = false;
if (!init) itPathTo = Iterators.cached(pathTo.iterator());
while (!foundValid && itPathTo.hasItem()) {
if (!init) itGPTo = Iterators.cached(itPathTo.item().genericParameters().iterator());
while (!foundValid && itGPTo.hasItem()) {
if (!init) foundValid = true;
init = false;
if (!foundValid) itGPTo.next();
}
if (!foundValid) itPathTo.next();
}
if (!foundValid) end = true;
}
}
tableau.add(row);
}
if (!end) return null;
return ResolvedName.newNameReference(path.getLast(), tableau);
}
/**
* @param fn function
* @return eventual overrides of the function, unifying those differing only in generic derivation
*/
public static Iterable<? extends IFunction> eventualOverrides(final IFunction fn) {
// Iterate over the eventually overridden functions,
// unifying those differing only through generic derivation.
final Set<IFunction> processedEO = new LinkedHashSet<>();
final Deque<IFunction> queueEO = new LinkedList<>();
queueEO.addLast(fn);
while (!queueEO.isEmpty()) {
final IFunction fnEO = queueEO.getFirst();
queueEO.removeFirst();
if (!processedEO.contains(fnEO)) {
processedEO.add(fnEO);
// Tail-recurse on the function's direct overrides.
for (final ResolvedName directOverride : fnEO.directOverrides())
queueEO.addLast((IFunction) directOverride.namedElement());
}
}
return processedEO;
}