feat(api): nvim_open_win() relative to tabline and laststatus #32006

Problem:  Anchoring a floating window to the tabline and laststatus is
          cumbersome; requiring autocommands and looping over all
          windows/tabpages.
Solution: Add new "tabline" and "laststatus" options to the `relative`
          field of nvim_open_win() to place a window relative to.

1 files changed, 13 insertions, 5 deletions

diff --git a/src/nvim/api/win_config.c b/src/nvim/api/win_config.c
index 45c9e3f56c..225189a3f9 100644
--- a/src/nvim/api/win_config.c
+++ b/src/nvim/api/win_config.c
@@ -101,10 +101,12 @@
 /// @param config Map defining the window configuration. Keys:
 ///   - relative: Sets the window layout to "floating", placed at (row,col)
 ///                 coordinates relative to:
-///      - "editor" The global editor grid
-///      - "win"    Window given by the `win` field, or current window.
-///      - "cursor" Cursor position in current window.
-///      - "mouse"  Mouse position
+///      - "cursor"     Cursor position in current window.
+///      - "editor"     The global editor grid.
+///      - "laststatus" 'laststatus' if present, or last row.
+///      - "mouse"      Mouse position.
+///      - "tabline"    Tabline if present, or first row.
+///      - "win"        Window given by the `win` field, or current window.
 ///   - win: |window-ID| window to split, or relative window when creating a
 ///      float (relative="win").
 ///   - anchor: Decides which corner of the float to place at (row,col):
@@ -699,7 +701,9 @@ Dict(win_config) nvim_win_get_config(Window window, Arena *arena, Error *err)
   FUNC_API_SINCE(6)
 {
   /// Keep in sync with FloatRelative in buffer_defs.h
-  static const char *const float_relative_str[] = { "editor", "win", "cursor", "mouse" };
+  static const char *const float_relative_str[] = {
+    "editor", "win", "cursor", "mouse", "tabline", "laststatus"
+  };
 
   /// Keep in sync with WinSplit in buffer_defs.h
   static const char *const win_split_str[] = { "left", "right", "above", "below" };
@@ -805,6 +809,10 @@ static bool parse_float_relative(String relative, FloatRelative *out)
     *out = kFloatRelativeCursor;
   } else if (striequal(str, "mouse")) {
     *out = kFloatRelativeMouse;
+  } else if (striequal(str, "tabline")) {
+    *out = kFloatRelativeTabline;
+  } else if (striequal(str, "laststatus")) {
+    *out = kFloatRelativeLaststatus;
   } else {
     return false;
   }