[O] [PATCH 1/2] clean up two macros in ob-comint

[Aaron Ecay]

* lisp/ob-comint.el (org-babel-comint-with-output,
org-babel-comint-in-buffer): clean up code.

This patch replaces some deeply nested ca/dr calls with ‘nth’, and
replaces a setq/unwind-protect/setq incantation with a simple let
binding.  Finally, it also restructures ’org-babel-comint-in-buffer’
to not needlessly save/restore match and excursion data if the buffer
process is not live, and to use with-current-buffer instead of
save-excursion+set-buffer
(info "(elisp) Excursions")
---
 lisp/ob-comint.el | 84 ++++++++++++++++++++++++++-----------------------------
 1 file changed, 40 insertions(+), 44 deletions(-)

diff --git a/lisp/ob-comint.el b/lisp/ob-comint.el
index 8b03e2d..4e2b352 100644
--- a/lisp/ob-comint.el
+++ b/lisp/ob-comint.el
@@ -48,12 +48,12 @@ BUFFER is checked with `org-babel-comint-buffer-livep'.  
BODY is
 executed inside the protection of `save-excursion' and
 `save-match-data'."
   (declare (indent 1))
-  `(save-excursion
+  `(progn
+     (unless (org-babel-comint-buffer-livep ,buffer)
+       (error "Buffer %s does not exist or has no process" ,buffer))
      (save-match-data
-       (unless (org-babel-comint-buffer-livep ,buffer)
-         (error "Buffer %s does not exist or has no process" ,buffer))
-       (set-buffer ,buffer)
-       ,@body)))
+       (with-current-buffer ,buffer
+        ,@body))))
 (def-edebug-spec org-babel-comint-in-buffer (form body))
 
 (defmacro org-babel-comint-with-output (meta &rest body)
@@ -69,46 +69,42 @@ elements are optional.
 This macro ensures that the filter is removed in case of an error
 or user `keyboard-quit' during execution of body."
   (declare (indent 1))
-  (let ((buffer (car meta))
-       (eoe-indicator (cadr meta))
-       (remove-echo (cadr (cdr meta)))
-       (full-body (cadr (cdr (cdr meta)))))
+  (let ((buffer (nth 0 meta))
+       (eoe-indicator (nth 1 meta))
+       (remove-echo (nth 2 meta))
+       (full-body (nth 3 meta)))
     `(org-babel-comint-in-buffer ,buffer
-       (let ((string-buffer "") dangling-text raw)
-        ;; setup filter
-        (setq comint-output-filter-functions
-              (cons (lambda (text) (setq string-buffer (concat string-buffer 
text)))
-                    comint-output-filter-functions))
-        (unwind-protect
-            (progn
-              ;; got located, and save dangling text
-              (goto-char (process-mark (get-buffer-process (current-buffer))))
-              (let ((start (point))
-                    (end (point-max)))
-                (setq dangling-text (buffer-substring start end))
-                (delete-region start end))
-              ;; pass FULL-BODY to process
-              ,@body
-              ;; wait for end-of-evaluation indicator
-              (while (progn
-                       (goto-char comint-last-input-end)
-                       (not (save-excursion
-                              (and (re-search-forward
-                                    (regexp-quote ,eoe-indicator) nil t)
-                                   (re-search-forward
-                                    comint-prompt-regexp nil t)))))
-                (accept-process-output (get-buffer-process (current-buffer)))
-                ;; thought the following this would allow async
-                ;; background running, but I was wrong...
-                ;; (run-with-timer .5 .5 'accept-process-output
-                ;;              (get-buffer-process (current-buffer)))
-                )
-              ;; replace cut dangling text
-              (goto-char (process-mark (get-buffer-process (current-buffer))))
-              (insert dangling-text))
-          ;; remove filter
-          (setq comint-output-filter-functions
-                (cdr comint-output-filter-functions)))
+       (let ((string-buffer "")
+            (comint-output-filter-functions
+             (cons (lambda (text) (setq string-buffer (concat string-buffer 
text)))
+                   comint-output-filter-functions))
+            dangling-text raw)
+        ;; got located, and save dangling text
+        (goto-char (process-mark (get-buffer-process (current-buffer))))
+        (let ((start (point))
+              (end (point-max)))
+          (setq dangling-text (buffer-substring start end))
+          (delete-region start end))
+        ;; pass FULL-BODY to process
+        ,@body
+        ;; wait for end-of-evaluation indicator
+        (while (progn
+                 (goto-char comint-last-input-end)
+                 (not (save-excursion
+                        (and (re-search-forward
+                              (regexp-quote ,eoe-indicator) nil t)
+                             (re-search-forward
+                              comint-prompt-regexp nil t)))))
+          (accept-process-output (get-buffer-process (current-buffer)))
+          ;; thought the following this would allow async
+          ;; background running, but I was wrong...
+          ;; (run-with-timer .5 .5 'accept-process-output
+          ;;            (get-buffer-process (current-buffer)))
+          )
+        ;; replace cut dangling text
+        (goto-char (process-mark (get-buffer-process (current-buffer))))
+        (insert dangling-text)
+
         ;; remove echo'd FULL-BODY from input
         (if (and ,remove-echo ,full-body
                  (string-match
-- 
1.8.4.1