Changed error system to CRTP, rough draft

tests/ErrorTest/main.cpp

@@ -3,29 +3,32 @@
 
 using namespace nb;
 
-class TestError : public nb::Error {
+class TestError : public ErrorBase<TestError> {
 public:
-    TestError(unsigned int code, nb::Error* const trace=nullptr) : _type("nb::TestError"), Error(code, ErrorCodeLookup<TestError>(code), trace) {}
-
-    friend const char* ErrorCodeLookup<TestError>(unsigned int);
-
-protected:
-    static const nb::ErrorCodeMap ErrorCodes;
-    const char* _type;
+    TestError(unsigned int code, std::exception* const trace=nullptr) 
+        : ErrorBase<TestError>(code, ErrorBase<TestError>::lookup(code), trace) {}
+    
+    enum ErrorCodes : unsigned int {
+        A, B, C, D
+    };
+    static const std::string type;
+    static const ErrorCodeMap ErrorMessages;
 };
 
-const ErrorCodeMap TestError::ErrorCodes{
-    {0, "Hey!"},
-    {1, "How"},
-    {2, "You"},
-    {3, "Doin"}
+const std::string TestError::type="TestError";
+const ErrorCodeMap TestError::ErrorMessages{
+    {TestError::ErrorCodes::A, "Hey!"},
+    {TestError::ErrorCodes::B, "How"},
+    {TestError::ErrorCodes::C, "You"},
+    {TestError::ErrorCodes::D, "Doin"}
 };
 
 int main() {
-    TestError a(0);
-    TestError b(1, &a);
-    TestError c(2, &b);
-    throw TestError(3, &c);
+    TestError d(TestError::ErrorCodes::D);
+    TestError c(TestError::ErrorCodes::C, &d);
+    TestError b(TestError::ErrorCodes::B, &c);
+    TestError a(TestError::ErrorCodes::A, &b);
+    throw Error(Error::ErrorCodes::UNDEFINED, &a);
 
     return 0;
 }