attempt fix

IPython/terminal/interactiveshell.py

@@ -588,6 +588,17 @@ def _merge_shortcuts(self, user_shortcuts):
         help="Display the current vi mode (when using vi editing mode)."
     ).tag(config=True)
 
+    prompt_line_number_format = Unicode(
+        "",
+        help="The format for line numbering, will be passed `line` (int, 1 based)"
+        " the current line number and `rel_line` the relative line number."
+        " for example to display both you can use the following template string :"
+        " c.TerminalInteractiveShell.prompt_line_number_format='{line: 4d}/{rel_line:+03d} | '"
+        " This will display the current line number, with leading space and a width of at least 4"
+        " character, as well as the relative line number 0 padded and always with a + or - sign."
+        " Note that when using Emacs mode the prompt of the first line may not update.",
+    ).tag(config=True)
+
     @observe('term_title')
     def init_term_title(self, change=None):
         # Enable or disable the terminal title.

IPython/terminal/prompts.py

@@ -25,11 +25,20 @@ def vi_mode(self):
             return '['+mode+'] '
         return ''
 
+    def current_line(self) -> int:
+        if self.shell.pt_app is not None:
+            return self.shell.pt_app.default_buffer.document.cursor_position_row or 0
+        return 0
 
     def in_prompt_tokens(self):
         return [
             (Token.Prompt, self.vi_mode()),
-            (Token.Prompt, "1 | "),
+            (
+                Token.Prompt,
+                self.shell.prompt_line_number_format.format(
+                    line=1, rel_line=-self.current_line()
+                ),
+            ),
             (Token.Prompt, "In ["),
             (Token.PromptNum, str(self.shell.execution_count)),
             (Token.Prompt, ']: '),
@@ -41,7 +50,12 @@ def _width(self):
     def continuation_prompt_tokens(self, width=None, *, lineno=None):
         if width is None:
             width = self._width()
-        prefix = " " * len(self.vi_mode()) + str(lineno + 1) + " | "
+        line = lineno + 1 if lineno is not None else 0
+        prefix = " " * len(
+            self.vi_mode()
+        ) + self.shell.prompt_line_number_format.format(
+            line=line, rel_line=line - self.current_line() - 1
+        )
         return [
             (
                 Token.Prompt,