made particle name constexpr string_view

corsika/detail/framework/core/ParticleProperties.inl

@@ -33,7 +33,7 @@ namespace corsika {
     return get_charge_number(code) * constants::e;
   }
 
-  constexpr std::string const& get_name(Code const code) {
+  constexpr std::string_view get_name(Code const code) {
     return particle::detail::names[static_cast<CodeIntType>(code)];
   }
 

corsika/framework/core/ParticleProperties.hpp

@@ -18,6 +18,8 @@
 #include <cstdint>
 #include <cmath>
 #include <iosfwd>
+#include <string_view>
+#include <type_traits>
 
 #include <corsika/framework/core/PhysicalUnits.hpp>
 
@@ -45,7 +47,7 @@ namespace corsika {
 
   //! Particle code according to PDG, "Monte Carlo Particle Numbering Scheme"
   PDGCode constexpr get_PDG(Code);
-  constexpr std::string const& get_name(Code); //!< name of the particle as string
+  constexpr std::string_view get_name(Code); //!< name of the particle as string
   TimeType constexpr get_lifetime(Code);       //!< lifetime
 
   //! true iff the particle is a hard-coded nucleus or Code::Nucleus

src/framework/core/pdxml_reader.py

@@ -338,7 +338,7 @@ def gen_properties(particle_db):
     string += "};\n"
     
     # name string table
-    string += "static const std::array<std::string const, size> names = {\n"
+    string += "static constexpr std::array<std::string_view, size> names = {\n"
     for p in particle_db.values():
         string += "  \"{name:s}\",\n".format(name = p['name'])            
     string += "};\n"
@@ -434,7 +434,7 @@ def gen_classes(particle_db):
         string += "   static constexpr HEPMassType mass{corsika::get_mass(code)};\n"
         string += "   static constexpr ElectricChargeType charge{corsika::get_charge(code)};\n"
         string += "   static constexpr int charge_number{corsika::get_charge_number(code)};\n"
-        string += "   inline static std::string const& name{corsika::get_name(code)};\n"
+        string += "   static constexpr std::string_view name{corsika::get_name(code)};\n"
         string += "   static constexpr bool is_nucleus{corsika::is_nucleus(code)};\n"
         if particle_db[cname]['isNucleus']:
             string += "   static constexpr int nucleus_A{corsika::get_nucleus_A(code)};\n"