compile with error on gcc5.3

[ho1messi]

I download the v0.11 source, when I try to build I got this error:

In file included from .../FTXUI-0.11/include/ftxui/dom/elements.hpp:131:0,
                 from .../FTXUI-0.11/src/ftxui/dom/blink.cpp:4:
.../FTXUI-0.11/include/ftxui/dom/take_any_args.hpp: In function ‘ftxui::Elements ftxui::unpack(Args ...)’:
.../FTXUI-0.11/include/ftxui/dom/take_any_args.hpp:24:33: error: expected primary-expression before ‘...’ token
   (Merge(vec, std::move(args)), ...);
                                 ^
.../FTXUI-0.11/include/ftxui/dom/take_any_args.hpp:24:33: error: expected ‘)’ before ‘...’ token
.../FTXUI-0.11/include/ftxui/dom/take_any_args.hpp:24:37: error: parameter packs not expanded with ‘...’:
   (Merge(vec, std::move(args)), ...);
                                     ^
.../FTXUI-0.11/include/ftxui/dom/take_any_args.hpp:24:37: note:         ‘args’
make[2]: *** [CMakeFiles/dom.dir/src/ftxui/dom/blink.cpp.o] Error 1
make[1]: *** [CMakeFiles/dom.dir/all] Error 2
make: *** [all] Error 2

my gcc version is 5.3.1, and in another computer with gcc8.5 it's ok.

[ArthurSonzogni]

Does this replies help you:
#262 (comment)

In particular, I believe you forget the -std=c++17 flag.

[ho1messi]

I use set(CMAKE_EXPORT_COMPILE_COMMANDS ON) in CMake to check the compile command, and found its already has a -std=gnu++1z

{
  "directory": ".../ftxui_test/build/ftxui",
  "command": "/opt/rh/devtoolset-4/root/usr/bin/c++   -I.../ftxui_test/ftxui/include -I.../ftxui_test/ftxui/src   
   -Wall -Wextra -pedantic -Werror -Wmissing-declarations -Wdeprecated -Wshadow -std=gnu++1z -o 
  CMakeFiles/dom.dir/src/ftxui/dom/blink.cpp.o -c .../ftxui_test/ftxui/src/ftxui/dom/blink.cpp",
  "file": ".../ftxui_test/ftxui/src/ftxui/dom/blink.cpp"
}

I also tried to change it to -std=c++17, remove target_compile_features(${library} PUBLIC cxx_std_17) in ftxui_set_options.cmake and add a set(CMAKE_CXX_FLAGS "-std=c++17") instead, but got the same error.

So, I think it can't be missing some flag.

[ho1messi]

Ok, I found that Folding Expressions is only supported by gcc 6+.

https://gcc.gnu.org/projects/cxx-status.html#cxx17