Feature proposal: C++11 range-for support
Hi, I have a few utility functions in my code that makes it nicer to iterate over elements of a mesh. I think they might also be useful for other users, so I'd like to present them here for discussion.
They can be used like this:
for(const auto &vh: iter_vertices(mesh)) {...} // vh is a VertexHandle&If you think this is useful, I would suggest making them member functions of GeometryKernel instead, so they can be used like this:
for(const auto &vh: mesh.iter_vertices()) {...}Let me know what you think of this, I can prepare a patch if you like.
My current implementation (a bit specific, not templated on mesh type) looks like this:
template<typename I> // iterator type
class RangeIter {
public:
RangeIter(I begin, I end) : begin_(begin), end_(end) {}
I begin() const {return begin_;}
I end() const {return end_;}
private:
I begin_, end_;
};
const inline RangeIter<OpenVolumeMesh::VertexIter>
iter_vertices(const PolyhedralMesh &mesh) {
return {mesh.vertices_begin(), mesh.vertices_end()};
}
const inline RangeIter<OpenVolumeMesh::EdgeIter>
iter_edges(const PolyhedralMesh &mesh) {
return {mesh.edges_begin(), mesh.edges_end()};
}
// ... etc for the other mesh elements(NB: the code uses C++11 uniform initialization, but I could refactor it to call the constructor explicitly)
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MasterEdited by Max LyonI'm definitely in favor of range-for support.
There exist already functions for most (all?) types of iterators which return a pair of start iterator and end iterators, e.g.
vertices()orboundary_halfface_halffaces(). Wouldn't it be enough to providebeginandendfunctions for these pairs of iterators? -
Developer
Ohhhh, yeah, that seems simpler. I'll give it a try later and create a PR if it works.
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DeveloperEdited by Martin Heistermann
Thinking about getting this to work for properties as well. Do I miss anything problematic about it, or could we just directly return a const& to a property vector? I assume it wasn't done in the first place to hide implementation details, but then again the return type is a vector::const_iterator and not something more generic.
This is the current code in ResourceManager:
typedef std::vector<BaseProperty*> Properties; Properties::const_iterator vertex_props_begin() const { return vertex_props_.begin(); } Properties::const_iterator vertex_props_end() const { return vertex_props_.end(); } //... Properties vertex_props_; -
Master
We should probably implement proper iterators for this. They could provide actual const access to the properties, hide the implementation details, and use your range based for interface for pairs of iterators.
