json.encode and json.decode finished. Also lots of refactoring.

luprex/core/cpp/json.hpp

@@ -0,0 +1,33 @@
+// Encode lua data structure into json, and decode them again.
+//
+// See the doc(http.jsonencode) to read about limitations of the encoder.
+//
+#ifndef JSON_HPP
+#define JSON_HPP
+
+#include "luastack.hpp"
+#include "wrap-string.hpp"
+#include <string_view>
+
+namespace json {
+    // Encode json.
+    //
+    // See doc(http.jsonencode) for a lot more information.
+    //
+    // Returns an error message.  If the error message is an
+    // empty string, then the encoding was successful.
+    //
+    eng::string encode(LuaStack &LS, LuaSlot in, eng::string &out, bool indent, int maxlen);
+
+    // Decode json.
+    //
+    // See doc(http.jsondecode) for a lot more information.
+    //
+    // The only error condition is syntactically invalid json.
+    // In that case, we return false.
+    //
+    bool decode(LuaStack &LS, LuaSlot out, std::string_view in);
+}
+    
+#endif // JSON_HPP
+