refactor: cancel the namespace Rust.

- all sub-functions are put into respective position.

src/yycc/panic.cpp

@@ -0,0 +1,39 @@
+#include "panic.hpp"
+#include "carton/termcolor.hpp"
+#include "patch/stream.hpp"
+#include <cstdlib>
+#include <iomanip>
+#include <iostream>
+#include <stacktrace>
+
+#define TERMCOLOR ::yycc::carton::termcolor
+
+using namespace yycc::patch::stream;
+
+namespace yycc::panic {
+
+    void panic(const char* file, int line, const std::u8string_view& msg) {
+        // Output message in stderr.
+        auto& dst = std::cerr;
+
+        // Print error message if we support it.
+        // Setup color
+        dst << TERMCOLOR::foreground(TERMCOLOR::Color::Red);
+        // File name and line number message
+        dst << "program paniked at " << std::quoted(file) << ":Ln" << line << std::endl;
+        // User custom message
+        dst << "note: " << msg << std::endl;
+        // Stacktrace message if we support it.
+        dst << "stacktrace: " << std::endl;
+        dst << std::stacktrace::current() << std::endl;
+        // Restore color
+        dst << TERMCOLOR::reset();
+
+        // Make sure all messages are flushed into screen.
+        dst.flush();
+
+        // Force exit
+        std::abort();
+    }
+
+} // namespace yycc::panic