package fail to install on mac-os systems (apple-clang)

[AlePalu]

Installing the R package on a mac-os system makes the compilation fail. Error reported:

In file included from R_Model.cpp:23:
   In file included from fdaPDE/fdaPDE/models.h:20:
   In file included from fdaPDE/fdaPDE/models/model_base.h:20:
   In file included from fdaPDE/fdaPDE/core/fdaPDE/mesh.h:20:
   fdaPDE/fdaPDE/core/fdaPDE/mesh/mesh.h:202:56: error: declaration of 'N' shadows template parameter
       static constexpr bool is_manifold = is_manifold<M, N>::value;
                                                          ^
   fdaPDE/fdaPDE/core/fdaPDE/mesh/mesh.h:59:22: note: template parameter is declared here
   template <int M, int N> class Mesh {
                        ^
   fdaPDE/fdaPDE/core/fdaPDE/mesh/mesh.h:202:56: error: default initialization of an object of const type 'const bool'
       static constexpr bool is_manifold = is_manifold<M, N>::value;
                                                          ^
                                                            = false
   fdaPDE/fdaPDE/core/fdaPDE/mesh/mesh.h:202:57: error: expected ';' at end of declaration list
       static constexpr bool is_manifold = is_manifold<M, N>::value;
                                                           ^
                                                           ;
   In file included from R_Model.cpp:23:
   In file included from fdaPDE/fdaPDE/models.h:20:
   In file included from fdaPDE/fdaPDE/models/model_base.h:21:
   In file included from fdaPDE/fdaPDE/core/fdaPDE/utils.h:24:
   fdaPDE/fdaPDE/core/fdaPDE/utils/type_erasure.h:222:28: error: use 'template' keyword to treat 'fn_ptrs' as a dependent template name
           size_ = (size<typename I::fn_ptrs<T_>>::value + ...);
                                     ^
                                     template 
   fdaPDE/fdaPDE/core/fdaPDE/utils/type_erasure.h:225:55: error: use 'template' keyword to treat 'fn_ptrs' as a dependent template name
           init_vtable<0, T_>(typename merge<typename I::fn_ptrs<T_>...>::type(), vtable_);
                                                         ^
                                                         template 
   fdaPDE/fdaPDE/core/fdaPDE/utils/type_erasure.h:230:67: error: use 'template' keyword to treat 'fn_ptrs' as a dependent template name
               base_ += size<typename std::decay<decltype(i)>::type::fn_ptrs<T_>>::value;
                                                                     ^
                                                                     template 
   In file included from R_Model.cpp:23:
   In file included from fdaPDE/fdaPDE/models.h:20:
   In file included from fdaPDE/fdaPDE/models/model_base.h:22:
   In file included from fdaPDE/fdaPDE/core/fdaPDE/pde.h:20:
   In file included from fdaPDE/fdaPDE/core/fdaPDE/pde/pde.h:29:
   fdaPDE/fdaPDE/core/fdaPDE/pde/differential_operators.h:48:51: error: template template argument has different template parameters than its corresponding template template parameter
       static constexpr bool value = has_instance_of<dT, decltype(std::declval<E>().get_operator_type())>::value;
                                                     ^
   fdaPDE/fdaPDE/core/fdaPDE/pde/differential_operators.h:36:1: note: too many template parameters in template template argument
   FDAPDE_DEFINE_DIFFERENTIAL_OPERATOR(dT,          dt         );
   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   fdaPDE/fdaPDE/core/fdaPDE/pde/differential_operators.h:28:5: note: expanded from macro 'FDAPDE_DEFINE_DIFFERENTIAL_OPERATOR'
       template <typename T, typename... Ts> class OP { };                                                                \
       ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   fdaPDE/fdaPDE/core/fdaPDE/utils/traits.h:58:11: note: previous template template parameter is here
   template <template <typename F> typename E, typename Tuple> struct has_instance_of { };
             ^~~~~~~~~~~~~~~~~~~~~
   In file included from R_Model.cpp:23:
   In file included from fdaPDE/fdaPDE/models.h:20:
   In file included from fdaPDE/fdaPDE/models/model_base.h:22:
   In file included from fdaPDE/fdaPDE/core/fdaPDE/pde.h:20:
   In file included from fdaPDE/fdaPDE/core/fdaPDE/pde/pde.h:29:
   fdaPDE/fdaPDE/core/fdaPDE/pde/differential_operators.h:48:27: error: default initialization of an object of const type 'const bool'
       static constexpr bool value = has_instance_of<dT, decltype(std::declval<E>().get_operator_type())>::value;
                             ^
                                   = false

Problem seems related to some apple-clang aspects which are ignored when compiling with gcc.

Compiler details:

─  installing source package ‘fdaPDE2’ ...
   ** using staged installation
   ** libs
   using C++ compiler: ‘Apple clang version 15.0.0 (clang-1500.0.40.1)’
   using C++17
   using SDK: ‘MacOSX14.0.sdk’

[AlePalu]

fdaPDE/fdaPDE-core@52ea8b3 solves the problem for the fdaPDE-core library

[AlePalu]

fdaPDE/fdaPDE-cpp@d197e82 solves the compilation problem also for the fdaPDE-cpp library. Waiting for an installation test of the R package on an actual macOS system.

[AlePalu]

Solved.