streamlines backends and reporting

src/main.cpp

@@ -118,7 +118,9 @@ int main(int argc, char *argv[]) {
         iss::cpu_ptr cpu{nullptr};
         std::string isa_opt(clim["isa"].as<std::string>());
         if(isa_opt.size()==0 || isa_opt == "?") {
-            std::cout<<"Available cores: "<<util::join(f.get_names(), ", ")<<std::endl;
+            auto list = f.get_names();
+            std::sort(std::begin(list), std::end(list));
+            std::cout<<"Available implementations (core|platform|backend):\n  - "<<util::join(list, "\n  - ")<<std::endl;
             return 0;
         } else if (isa_opt.find('|') != std::string::npos) {
             std::tie(cpu, vm) = f.create(isa_opt+"|"+clim["backend"].as<std::string>(), clim["gdb-port"].as<unsigned>());