/**
 * Ways to continue visiting a snapshot hierarchy after an entry has been visited.
 *
 * @see java.nio.file.FileVisitResult
 */
public enum SnapshotVisitResult {

    /**
     * Continue visiting. When returned after visiting a directory,
     * the entries in the directory will be visited next.
     */
    CONTINUE,

    /**
     * Terminate visiting immediately.
     */
    TERMINATE,

        }
    }

    private static void checkForCyclesFor(TaskInternal task, Set<TaskInternal> visited, Set<TaskInternal> visiting) {
        if (visited.contains(task)) {
            // Already checked
            return;
        }
        if (!visiting.add(task)) {
            // Visiting dependencies -> have found a cycle

                cycle.removeLast();
                stateMap.put(v, DfsState.VISITED);
            } else if (state == DfsState.VISITING) {
                // we are already visiting this vertex, this mean we have a cycle
                int pos = cycle.lastIndexOf(v.label);
                List<String> ret = cycle.subList(pos, cycle.size());
                ret.add(v.label);
                return ret;
            }
        }

    /**
     * Called when starting to visit a file collection. Can return true to continue with visiting or false to skip this collection and its contents.
     *
     * <p>When a file collection represents a container of file collections, the children of the file collection are visited in order. Visiting a child works in the

                    stateMap.put(v, DfsState.VISITED);
                } else if (state == DfsState.VISITING) {
                    // we are already visiting this vertex, this mean we have a cycle
                    int pos = cycle.lastIndexOf(v);
                    List<String> ret = cycle.subList(pos, cycle.size());
                    ret.add(v);
                    return ret;
                }
            }
        }

                cycle.removeLast();
                stateMap.put(v, DfsState.VISITED);
            } else if (state == DfsState.VISITING) {
                // we are already visiting this vertex, this mean we have a cycle
                int pos = cycle.lastIndexOf(v.label);
                List<String> ret = cycle.subList(pos, cycle.size());
                ret.add(v.label);
                return ret;
            }
        }

			w.fields[j] = *f
		}
		j++
	}
	return w.fields[:j]
}

type visibleFieldsWalker struct {
	byName   map[string]int
	visiting map[Type]bool
	fields   []StructField
	index    []int
}

// walk walks all the fields in the struct type t, visiting
// fields in index preorder and appending them to w.fields
// (this maintains the required ordering).
// Fields that have been overridden have their

                    stateMap.put(v, DfsState.VISITED);
                } else if (state == DfsState.VISITING) {
                    // we are already visiting this vertex, this mean we have a cycle
                    int pos = cycle.lastIndexOf(v);
                    List<String> ret = cycle.subList(pos, cycle.size());
                    ret.add(v);
                    return ret;
                }
            }
        }

    }

    /**
     * Starts visiting the children of the most recently visited node.
     */
    public void startChildren() {
        if (seenRootChildren) {
            prefix.append(lastChild ? "     " : "|    ");
        }
        seenRootChildren = true;
    }

    /**
     * Completes visiting the children of the node which most recently started visiting children.
     */

//
//	var do func(ir.Node) bool
//	do = func(x ir.Node) bool {
//		... processing BEFORE visiting children ...
//		if ... should visit children ... {
//			ir.DoChildren(x, do)
//			... processing AFTER visiting children ...
//		}
//		if ... should stop parent DoChildren call from visiting siblings ... {
//			return true
//		}
//		return false
//	}
//	do(root)
//