What's wrong
Two places in Coder/Languages/CppGenerator.cs write constexpr without checking the type:
:794 (SpellStorage for FieldDeclaration):616 (GenerateField for a constant VariableDeclaration)
string maps to std::string (line 48). A constant string field therefore comes out as static constexpr std::string / inline constexpr std::string.
Failure scenario
new FieldDeclaration("Name", "string") {
IsStatic = true, IsConstant = true,
InitialValue = Literal.Text("a string longer than fifteen chars") }Inside a struct this generates:
static constexpr std::string Name = "a string longer than fifteen chars";
g++ 13.3 with -std=c++20 rejects it: "is not a constant expression because it refers to a result of 'operator new'".
Short strings compile only because libstdc++'s small-string buffer holds them. Whether the output builds depends on the literal's length, and it also varies by standard library. Under C++17, constexpr std::string is never valid.
I reproduced this with the built ktsu.Coder.dll and g++ 13.3.
Suggested fix / acceptance criteria
- For a type that isn't a literal type (at least
std::string), write one of:
static inline const std::string / inline const std::stringstd::string_view for the constant: static constexpr std::string_view
- Add a long-string constant case to
CppGeneratedSourceCompilesTests.
What's wrong
Two places in
Coder/Languages/CppGenerator.cswriteconstexprwithout checking the type::794(SpellStorageforFieldDeclaration):616(GenerateFieldfor a constantVariableDeclaration)stringmaps tostd::string(line 48). A constant string field therefore comes out asstatic constexpr std::string/inline constexpr std::string.Failure scenario
Inside a struct this generates:
g++ 13.3 with
-std=c++20rejects it: "is not a constant expression because it refers to a result of 'operator new'".Short strings compile only because libstdc++'s small-string buffer holds them. Whether the output builds depends on the literal's length, and it also varies by standard library. Under C++17,
constexpr std::stringis never valid.I reproduced this with the built
ktsu.Coder.dlland g++ 13.3.Suggested fix / acceptance criteria
std::string), write one of:static inline const std::string/inline const std::stringstd::string_viewfor the constant:static constexpr std::string_viewCppGeneratedSourceCompilesTests.