Yes, this is exactly right. Thank you Bjorn. The reason is that I cannot define a generic assignment operator because the assignment operator is required to be a member function. If you provide your own assignment operator that is generic you can call the boost::polygon::assign from within it, but you would want to add the same SFINAE guards to it that I use on the definition of assign() to make it concept type safe. Regards, Luke From: boost-users-bounces@lists.boost.org [mailto:boost-users-bounces@lists.boost.org] On Behalf Of Björn Piltz Sent: Monday, October 17, 2011 4:25 AM To: boost-users@lists.boost.org Subject: Re: [Boost-users] [boost::polygon::operators] Boolean operations compiler error You could try: boost::polygon::assign(p3, p1&p2); Or, if you're using namespace boost::polygon::operators, you could write: p3 = p1; p3 &= p2; 2011/10/17 Dimitris Dakopoulos <dakopoulos@gmail.com<mailto:dakopoulos@gmail.com>> Hello all, I'm using a custom polygon set (PolygonCollection) according to the guidelines here: http://www.boost.org/doc/libs/1_47_0/libs/polygon/doc/gtl_custom_polygon_set... There is one case that I don't get any compiler error: PolygonCollection p1, p2; p1 & p2; There is this case that I do have an error: PolygonCollection p1, p2; PolygonCollection p3 = p1 & p2; The error is: error: conversion from 'boost::polygon::polygon_set_view<PolygonCollection, PolygonCollection, 1>' to non-scalar type 'PolygonCollection' requested There is also this case that I have a compiler error: PolygonCollection p1,p2,p3; p3 = p1 & p2; The error is:error: no match for 'operator=' in 'p3 = boost::polygon::operators::operator&(const geometry_type_1&, const geometry_type_2&) [with geometry_type_1 = PolygonCollection, geometry_type_2 = PolygonCollection](((const PolygonCollection&)((const PolygonCollection*)(& p1))))' /xxx/Polygon.hpp:182: note: candidates are: PolygonCollection& PolygonCollection::operator=(const PolygonCollection&) (You can notice that I have overloaded the operator= for my custom polygon set but I got the same error without the suggestion before my implementation) Any ideas are welcomed! Dimitris _______________________________________________ Boost-users mailing list Boost-users@lists.boost.org<mailto:Boost-users@lists.boost.org> http://lists.boost.org/mailman/listinfo.cgi/boost-users