First steps of implementing command-line processing in the ascii driver.

luprex/cpp/drv/readline.hpp

@@ -28,15 +28,19 @@ public:
     void set_print_callback(print_callback cb);
     
     // change the prompt.
-    void set_prompt(const std::u32string &prompt);
+    void set_prompt(std::string_view prompt);
 
     // Use this to print anything on the console.
-    void print(const std::u32string &cps);
+    //
+    // if the string doesn't end in a newline, one will
+    // be automatically added.
+    //
+    void printline(std::string_view cps);
 
     // Whenever the user types a character, call 'putcode'. If the code is
     // newline, this returns the line of text that was entered, including the
     // newline.  Otherwise returns empty string. Backspace is handled here.
-    std::u32string putcode(char32_t codepoint);
+    std::string putcode(char32_t codepoint);
 };