Fix sending of long code strings to REPL using temporary files (issue: immerrr#89)

Author: arbv

lua-mode.el

@@ -1779,12 +1779,53 @@ When called interactively, switch to the process buffer."
   (set-marker lua-region-end (or arg (point))))
 
 (defun lua-send-string (str)
-  "Send STR plus a newline to Lua subprocess.
+  "Load STR plus a newline into Lua subprocess.
 
 If `lua-process' is nil or dead, start a new process first."
-  (unless (string-equal (substring str -1) "\n")
-    (setq str (concat str "\n")))
-  (process-send-string (lua-get-create-process) str))
+  (let ((tmp-file (make-temp-file "luamode" nil ".tmp"))
+        (lua-process (lua-get-create-process)))
+    ;; write data into temporary file
+    (with-temp-buffer
+      (insert (if (string-equal (substring str -1) "\n")
+                  str
+                (concat str "\n")))
+      (write-file tmp-file))
+    ;; evaluate data in the temporary file and then remove it
+    (process-send-string
+     lua-process
+     (format (concat
+              "\n"
+              "local tmp = '%s';"
+              "local res, e = pcall(function () "
+              "  local do_loadstring = loadstring or load;"
+              ""
+              "  local f, e = io.open(tmp, 'r');" ; open temporary file
+              "  if e then "
+              "    os.remove(tmp);"
+              "    error(e);"
+              "    return;"
+              "  end "
+              ""
+              "  local cont, e = f:read('*all');" ; read all data
+              "  if e then "
+              "    os.remove(tmp);"
+              "    error(e);"
+              "    return;"
+              "  end "
+              ""
+              "  f:close(); f = nil;" ; close and remove file
+              "  os.remove(tmp);"
+              ""
+              "  local f, e = do_loadstring(cont);" ; handle chunk
+              "  if e then "
+              "    error(e);"
+              "    return;"
+              "  end "
+              ""
+              "  return f();" ; execute chunk
+              "end);"
+              "if e then _, _ = os.remove(tmp); error(e); end" ; handle error, if any
+              "\n") tmp-file))))
 
 (defun lua-send-current-line ()
   "Send current line to Lua subprocess, found in `lua-process'.