From b5c33ca2b769e87e86e1ed6d2c19dfce14c242c0 Mon Sep 17 00:00:00 2001
From: nicm <nicm>
Date: Thu, 25 Dec 2025 18:05:15 +0000
Subject: [PATCH] Add selection_mode format variable for copy mode, from Mike
 Jonkmans in GitHub issue 4773.

---
 tmux.1        |  1 +
 window-copy.c | 12 ++++++++++++
 2 files changed, 13 insertions(+)

diff --git a/tmux.1 b/tmux.1
index fe228dd2..a93a002e 100644
--- a/tmux.1
+++ b/tmux.1
@@ -6238,6 +6238,7 @@ The following variables are available, where appropriate:
 .It Li "selection_active" Ta "" Ta "1 if selection started and changes with the cursor in copy mode"
 .It Li "selection_end_x" Ta "" Ta "X position of the end of the selection"
 .It Li "selection_end_y" Ta "" Ta "Y position of the end of the selection"
+.It Li "selection_mode" Ta "" Ta "Selection mode"
 .It Li "selection_present" Ta "" Ta "1 if selection started in copy mode"
 .It Li "selection_start_x" Ta "" Ta "X position of the start of the selection"
 .It Li "selection_start_y" Ta "" Ta "Y position of the start of the selection"
diff --git a/window-copy.c b/window-copy.c
index f8700555..87d0dea8 100644
--- a/window-copy.c
+++ b/window-copy.c
@@ -956,6 +956,18 @@ window_copy_formats(struct window_mode_entry *wme, struct format_tree *ft)
 		format_add(ft, "selection_present", "0");
 	}
 
+	switch (data->selflag) {
+	case SEL_CHAR:
+		format_add(ft, "selection_mode", "char");
+		break;
+	case SEL_WORD:
+		format_add(ft, "selection_mode", "word");
+		break;
+	case SEL_LINE:
+		format_add(ft, "selection_mode", "line");
+		break;
+	}
+
 	format_add(ft, "search_present", "%d", data->searchmark != NULL);
 	format_add(ft, "search_timed_out", "%d", data->timeout);
 	if (data->searchcount != -1) {