In the tmux-repl, it tackles the situations where there is already some other tmux pane open

and we want to send text (or do other works) in that specific pane.

rc/windowing/repl/tmux.kak

@@ -35,6 +35,35 @@ define-command tmux-repl-window -params 0.. -command-completion -docstring "Crea
     tmux-repl-impl 'new-window' %arg{@}
 }
 
+define-command -params 0..1 tmux-repl-set-pane -docstring %{
+        tmux-repl-set-pane [pane number]: Set an existing tmux pane for repl interaction
+        If the address of new pane is not given, next pane is used
+        (To get the pane number in tmux,
+        use 'tmux display-message -p '#{pane_id}'" in that pane)
+    } %{
+    evaluate-commands %sh{
+        if [ -z "$TMUX" ]; then
+            echo 'fail This command is only available in a tmux session'
+            exit
+        fi
+        if [ $# -eq 0 ]; then
+            curr_pane="$(tmux display-message -p '#{pane_id}')"
+            curr_pane_no="${curr_pane:1}"
+            tgt_pane=$((curr_pane_no+1))
+        else
+            tgt_pane="$1"
+        fi
+        curr_win="$(tmux display-message -p '#{window_id}')" 
+        curr_win_no="${curr_win:1}"
+        current=$(tmux list-panes -t $curr_win_no -F \#D)
+        if [[ "$current" =~ "%"$tgt_pane ]]; then
+            printf "set-option current tmux_repl_id '%s'" $(tmux display-message -p '#{session_id}:#{window_id}.')%$tgt_pane
+        else
+            echo 'fail The correct pane is not there. Activate using tmux-terminal-* or some other way'
+        fi
+    }
+}
+
 define-command -hidden tmux-send-text -params 0..1 -docstring %{
         tmux-send-text [text]: Send text to the REPL pane.
         If no text is passed, then the selection is used