While editing code, I tend to keep a REPL open in tmux to try out the code I'm writing.

Adding the following code to my ~/.textadept/init.lua file, enables me to send the selected text in TextAdept to tmux using Ctrl-t. A little bit easier for my fingers ...

local function send_selection_to_tmux()
  local txt = buffer:get_sel_text();
  spawn("tmux set-buffer '" .. txt .. "\n'");
  spawn("tmux paste-buffer -d");
end

keys['ctrl+t'] = send_selection_to_tmux