Stream_support: Document that WKT can also handle 3D points (#8669)

## Summary of Changes

Fix in the documentation, namely that also 3D points may be used.

## Release Management

* Affected package(s): Stream_support

Stream_support/include/CGAL/IO/WKT.h

@@ -156,9 +156,9 @@ bool read_multi_point_WKT(std::istream& in,
 //!
 //! The first line starting with LINESTRING in the stream will be used.
 //!
-//! \tparam Linestring must be a model of `RandomAccessRange` of `CGAL::Point_2`,
+//! \tparam Linestring must be a model of `RandomAccessRange` of `CGAL::Point_2` or `CGAL::Point_3`,
 //! and have:
-//! - a function `push_back()` that takes a `CGAL::Point_2`.
+//! - a function `push_back()` that takes a point.
 //! - a function `clear()`,
 //! - a function `resize()` that takes a `size_type`
 //! - an `operator[]()` that takes a `size_type`.
@@ -166,6 +166,7 @@ bool read_multi_point_WKT(std::istream& in,
 //! \attention Only %Cartesian Kernels with double or float  as `FT` are supported.
 //!
 //! \see `CGAL::Point_2`
+//! \see `CGAL::Point_3`
 template<typename LineString>
 bool read_linestring_WKT(std::istream& in,
                          LineString& polyline)
@@ -209,7 +210,6 @@ bool read_linestring_WKT(std::istream& in,
 //!
 //! \attention Only %Cartesian Kernels with double or float  as `FT` are supported.
 //!
-//! \see `CGAL::Point_2`
 template<typename MultiLineString>
 bool read_multi_linestring_WKT(std::istream& in,
                                MultiLineString& mls)
@@ -359,11 +359,12 @@ bool read_multi_polygon_WKT(std::istream& in,
 //!
 //! \brief writes `point` into a WKT stream.
 //!
-//! \tparam Point is a `CGAL::Point_2`
+//! \tparam Point is a `CGAL::Point_2` or `CGAL::Point_3`
 //!
 //! \attention Only %Cartesian Kernels with double or float  as `FT` are supported.
 //!
 //! \see `CGAL::Point_2`
+//! \see `CGAL::Point_3`
 template<typename Point>
 std::ostream& write_point_WKT(std::ostream& out,
                               const Point& point)
@@ -399,11 +400,12 @@ std::ostream& write_polygon_WKT(std::ostream& out,
 //!
 //! \brief writes the content of `ls` into a WKT stream.
 //!
-//! \tparam LineString must be a `RandomAccessRange` of `CGAL::Point_2`.
+//! \tparam LineString must be a `RandomAccessRange` of `CGAL::Point_2` or `CGAL::Point_3`.
 //!
 //! \attention Only %Cartesian Kernels with double or float  as `FT` are supported.
 //!
 //!\see `CGAL::Point_2`
+//!\see `CGAL::Point_3`
 template<typename LineString>
 std::ostream& write_linestring_WKT(std::ostream& out,
                                    LineString ls)
@@ -420,11 +422,12 @@ std::ostream& write_linestring_WKT(std::ostream& out,
 //!
 //! \brief writes the content of `mp` into a WKT stream.
 //!
-//! \tparam MultiPoint must be a `RandomAccessRange` of `CGAL::Point_2`.
+//! \tparam MultiPoint must be a `RandomAccessRange` of `CGAL::Point_2` or `CGAL::Point_3`.
 //!
 //! \attention Only %Cartesian Kernels with double or float  as `FT` are supported.
 //!
 //!\see `CGAL::Point_2`
+//!\see `CGAL::Point_2`
 template<typename MultiPoint>
 std::ostream& write_multi_point_WKT(std::ostream& out,
                                     MultiPoint& mp)

Stream_support/test/Stream_support/test_WKT.cpp

@@ -3,8 +3,8 @@
 #include <CGAL/IO/WKT.h>
 
 #include <CGAL/Exact_predicates_inexact_constructions_kernel.h>
-
 #include <fstream>
+#include <sstream>
 #include <vector>
 #include <cassert>
 
@@ -17,7 +17,69 @@ typedef std::vector<Point>                                            MultiPoint
 typedef std::vector<Linestring>                                       MultiLinestring;
 typedef std::vector<Poly>                                             MultiPolygon;
 
+
+typedef CGAL::Point_3<Kernel>                                         Point3;
+typedef std::vector<Point3>                                           Linestring3;
+typedef std::vector<Point3>                                           MultiPoint3;
+typedef std::vector<Linestring3>                                      MultiLinestring3;
 ////////////////////////////////////////////////////////////////////////////////////////////////////
+
+bool test_WKT_3D()
+{
+  {
+    Point3 p(1,2,3), q(0,0,0);
+    std::stringstream ss;
+    CGAL::IO::write_point_WKT(ss, p);
+    bool b = CGAL::IO::read_point_WKT(ss, q);
+    assert(b);
+    CGAL_USE(b);
+    assert(p == q);
+  }
+  {
+    Point3 p(1,2,3), q(3,2,1);
+    MultiPoint3  mp, mq;
+    mp.push_back(p);
+    mp.push_back(q);
+    std::stringstream ss;
+    CGAL::IO::write_multi_point_WKT(ss, mp);
+    bool b = CGAL::IO::read_multi_point_WKT(ss, mq);
+    assert(b);
+    CGAL_USE(b);
+    assert(mp == mq);
+  }
+  {
+    Point3 p(1,2,3), q(3,2,1);
+    Linestring3  mp, mq;
+    mp.push_back(p);
+    mp.push_back(q);
+    std::stringstream ss;
+    CGAL::IO::write_linestring_WKT(ss, mp);
+    bool b = CGAL::IO::read_linestring_WKT(ss, mq);
+    assert(b);
+    CGAL_USE(b);
+    assert(mp == mq);
+  }
+  {
+    Point3 p(1,2,3), q(3,2,1), r(4,5,6);
+    Linestring3  mp, mq;
+    mp.push_back(p);
+    mp.push_back(q);
+    mq.push_back(p);
+    mq.push_back(r);
+    MultiLinestring3  mmp, mmq;
+    mmp.push_back(mp);
+    mmp.push_back(mq);
+    std::stringstream ss;
+    CGAL::IO::write_multi_linestring_WKT(ss, mmp);
+    bool b = CGAL::IO::read_multi_linestring_WKT(ss, mmq);
+    assert(b);
+    CGAL_USE(b);
+    assert(mmp == mmq);
+  }
+  return true;
+}
+
+
 ////////////////////////////////////////////////////////////////////////////////////////////////////
 /// Read
 
@@ -273,6 +335,8 @@ int main()
   assert(ok);
   ok = test_write_WKT();
   assert(ok);
+  ok = test_WKT_3D();
+  assert(ok);
 
   return EXIT_SUCCESS;
 }