Iterable Class

Detailed Description

Helper class to allow collection types to support iterators.

Any class that inherits Iterable will support C++11 range-for loops as well as anything else that works with forward iterators.

Iterable types implement std::forward_iterator_tag functionality.

The purpose of this class is to allow certain C++11 and newer features to work with exising classes in the API. For example, you can iterate over the map's layers:

for (auto* layer : *(map->operationalLayers()))
{
  ...
}

In addition to the C++11 range-based for looping, you can also use std::for_each. For example:

QStringList layerNames;
std::for_each(operationalLayers->cbegin(), operationalLayers->cend(), [&layerNames](Layer* layer)
{ // gather all the names of the layers
  layerNames.append(layer->name());
});

Another example is searching for a layer with a specific name:

auto* opLayers = scene->operationalLayers();
auto it = std::find_if(opLayers->constBegin(), opLayers->constEnd(), [](Layer* l)
{
  return l->name() == "MyLayer";
});

if (it == opLayers->constEnd())
  return; // no match

// we found a match
Layer* match = *it;

Iterable also works with value objects. For example, you can iterate over the points in an ImmutablePointCollection:

const ImmutablePointCollection points = getPoints();
for (const Point& p : points)
{
  // do stuff with the points...
}