A simple little design-by-contract library to test out more advanced c++20 features. Looks like clang doesn't do std::source_location right. See https://github.com/llvm/llvm-project/issues/56379

PPP3/dbc.h

@@ -0,0 +1,59 @@
+#include <string>
+#include <source_location>
+#include <fmt/core.h>
+
+using namespace std;
+
+namespace dbc {
+  class Error {
+    public:
+      const string message;
+      Error(string m) : message{m} {}
+      Error(const char *m) : message{m} {}
+  };
+
+  class CheckError : public Error {};
+
+  class SentinelError : public Error {};
+  class PreCondError : public Error {};
+  class PostCondError : public Error {};
+
+  void log(const string &message, std::source_location loc = std::source_location::current()) {
+    fmt::print("[{}:{}:{}] {}\n", loc.file_name(), loc.function_name(), loc.line(), message);
+  }
+
+  void sentinel(const string &message, std::source_location loc = std::source_location::current()) {
+    string err = fmt::format("[SENTINEL! {}:{}:{}:{}] {}\n",
+          loc.file_name(), loc.function_name(),
+          loc.line(), loc.column(), message);
+    throw SentinelError{err};
+  }
+
+  void pre(const string &message, std::function<bool()> tester, std::source_location loc = std::source_location::current()) {
+    if(!tester()) {
+      string err = fmt::format("[PRE! {}:{}:{}:{}] {}\n",
+          loc.file_name(), loc.function_name(),
+          loc.line(), loc.column(), message);
+      throw PreCondError{err};
+    }
+  }
+
+  void post(const string &message, std::function<bool()> tester, std::source_location loc = std::source_location::current()) {
+    if(!tester()) {
+      string err = fmt::format("[POST! {}:{}:{}:{}] {}\n",
+          loc.file_name(), loc.function_name(),
+          loc.line(), loc.column(), message);
+      throw PostCondError{err};
+    }
+  }
+
+  void check(bool test, const string &message, std::source_location loc = std::source_location::current()) {
+
+    if(!test) {
+      string err = fmt::format("[CHECK! {}:{}:{}:{}] {}\n",
+          loc.file_name(), loc.function_name(),
+          loc.line(), loc.column(), message);
+      throw CheckError{err};
+    }
+  }
+}