Partition_2: add Container template parameter to Partition_traits_2

[RajdeepKushwaha5]

Fixes #7545

The Container type used for the vertices of the output Polygon_2 was hardcoded to std::list<Point_2> inside Partition_traits_2. This prevented users from requesting a different container (e.g., std::vector<Point_2>) for the output polygons produced by all partitioning functions (y_monotone_partition_2, approx_convex_partition_2, greene_approx_convex_partition_2, optimal_convex_partition_2).

Root Cause

Partition_traits_2.h line 65 had:
typedef ::std::list<Point_2> Container;
with no mechanism for users to change it.

Fix

Add a third template parameter to Partition_traits_2:
class Container_ = std::list<typename boost::property_traits::key_type>

The parameter defaults to std::list<Point_2>, preserving full backward
compatibility with all existing uses of Partition_traits_2<K> and
Partition_traits_2<K, PM>.

Users can now write:
typedef CGAL::Partition_traits_2<K, CGAL::Identity_property_map<K::Point_2>,
std::vector<K::Point_2>> VecTraits;
std::listVecTraits::Polygon_2 parts;
CGAL::optimal_convex_partition_2(pts.begin(), pts.end(),
std::back_inserter(parts), VecTraits());

Files Changed

• Partition_2/include/CGAL/Partition_traits_2.h

  • Forward declaration: added Container_ template param with default.
  • Class definition: added Container_ to template param list and Self typedef.
  • Replaced hardcoded typedef ::std::list<Point_2> Container with
    typedef Container_ Container.

• Partition_2/doc/Partition_2/CGAL/Partition_traits_2.h

  • Added \tparam Container documentation.
  • Updated template declaration in doc header.
  • Updated Container typedef description.

• Partition_2/doc/Partition_2/PackageDescription.txt

  • Updated class listing from Partition_traits_2<R,P> to
    Partition_traits_2<R,P,Container>.

[Copilot]

Pull request overview

Adds a Container template parameter to CGAL::Partition_traits_2 so users can choose the vertex container type (e.g., std::vector<Point_2>) for the output Polygon_2 produced by Partition_2 algorithms, while preserving the existing defaults for backward compatibility.

Changes:

• Extend Partition_traits_2 with a third template parameter Container_ (defaulting to std::list<Point_2>-equivalent) and use it for the Container typedef.
• Update the reference documentation for Partition_traits_2 to document the new template parameter and updated typedef.
• Update the package description class listing to reflect the new template signature.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 2 comments.

File	Description
Partition_2/include/CGAL/Partition_traits_2.h	Adds the Container_ template parameter and wires it into the Polygon_2 container type.
Partition_2/doc/Partition_2/CGAL/Partition_traits_2.h	Documents the new container template parameter and updates the Container typedef description.
Partition_2/doc/Partition_2/PackageDescription.txt	Updates the class list to show Partition_traits_2<R,P,Container>.

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[Copilot]

This change adds a new Container_ template parameter intended to let callers choose the output polygon vertex container, but there isn't a regression test exercising a non-default container (e.g., std::vector<Point_2>) with at least one partitioning function. Adding a small compile+run test would help ensure the new API works and stays supported.

[Copilot]

In the documentation header, the template parameter is named Container, and the nested typedef is written as typedef Container Container;. This effectively redefines the template parameter name in the same scope and does not document the actual container type alias (it should alias the template parameter type, not itself). Consider renaming the template parameter to Container_ (matching the implementation) and defining typedef Container_ Container; so the documented API matches the real one and parses cleanly.

[afabri]

Before pushing you should test locally. This would have revealed the typedef Container Container; error copilot reports you.
Also please stop flooding this repository with pull requests, where one has the impression that you just started an agent.

[afabri]

Suggested change

	value type `Point_2`. Defaults to `std::list<Point_2>`.
	value type `R::Point_2`. Defaults to `std::list<R::Point_2>`.