Add support for > and >> prompts with new readline

luprex/cpp/drv/driver.cpp

@@ -214,6 +214,11 @@ class Driver {
 
     void handle_console_input() {
         read_console_recently_ = false;
+        uint32_t promptlen;
+        const char *promptdata;
+        engw.get_console_prompt(&engw, &promptlen, &promptdata);
+        CodepointString prompt = ReadlineDevice::from_utf8(std::string_view(promptdata, promptlen), nullptr);
+        readline_device_.set_prompt(prompt);
         while (true) {
             CodepointString cps = console_read();
             if (cps.size() == 0) break;

luprex/cpp/drv/readline.cpp

@@ -117,6 +117,11 @@ void ReadlineDevice::set_print_callback(print_callback cb) {
     print_cb_ = cb;
 }
 
+void ReadlineDevice::set_prompt(const CodepointString &prompt) {
+    desired_prompt_ = prompt;
+    echo_command();
+}
+
 void ReadlineDevice::erase_command() {
     int ccsize = current_prompt_.size() + current_command_.size();
     if (ccsize > 0) {
@@ -168,6 +173,7 @@ CodepointString ReadlineDevice::putcode(char32_t c) {
         desired_command_.clear();
         current_prompt_.clear();
         current_command_.clear();
+        echo_command();
         return result;
     } else if ((c == '\b') || (c == 127)) {
         int len = desired_command_.size();

luprex/cpp/drv/readline.hpp

@@ -19,8 +19,9 @@ private:
     CodepointString current_prompt_;
     char32_t readline_lastc_;
 
-    void echo_command();
     void erase_command();
+    void echo_command();
+
 
 public:
     ReadlineDevice();
@@ -30,6 +31,7 @@ public:
     
     // change the prompt.
     void set_prompt(const CodepointString &prompt);
+    void set_prompt_utf8(const std::string &prompt);
 
     // Use this to print anything on the console.
     void print(const CodepointString &cps);
@@ -44,8 +46,9 @@ public:
     static std::string to_utf8(const CodepointString &cps);
 
     // This can be used to convert UTF8 to a codepoint string.
-    // Some of the bytes may not be consumed.  Returns the Codepoint
-    // string and the number of bytes consumed.
+    // Some of the bytes may not be consumed, if the source contains
+    // a partial utf-8 sequence.  Returns the Codepoint string and the
+    // number of bytes consumed.
     static CodepointString from_utf8(std::string_view source, int *consumed);
 };