Add option to always send a trailing newline

doc/tslime.txt

@@ -50,3 +50,11 @@ targets easier:
 *g:tslime_always_current_window*
                         When selecting a target, always choose the current
                         tmux window without prompting.
+
+                                                        *g:tslime_ensure_newline*
+When sending text selected by a |characterwise| motion or text object, the
+trailing newline may be omitted. This can cause problems when sending text to
+a shell or REPL that expects a trailing newline after each command. To ensure
+a trailing newline is always sent, add the following line to your vimrc: >
+
+   let g:tslime_ensure_newline = 1

plugin/tslime.vim

@@ -15,7 +15,9 @@ function! Send_to_Tmux(text)
     call <SID>Tmux_Vars()
   endif
 
-  call system("tmux load-buffer -b tslime -", a:text)
+  let add_newline = exists("g:tslime_ensure_newline") && (a:text[-1:] != "\n")
+
+  call system("tmux load-buffer -b tslime -", a:text . (add_newline ? "\n" : ""))
   call system("tmux paste-buffer -d -b tslime -t " . s:tmux_target())
 endfunction