emacs: Use 'and' instead of 'when' when the return value matters

Also do so for some 'if' forms that lack an ELSE part.
Even go as far as using 'and' and 'not' instead of 'unless'.

1 files changed, 18 insertions, 19 deletions

diff --git a/emacs/notmuch-lib.el b/emacs/notmuch-lib.el
index 886da99f..98056eb6 100644
--- a/emacs/notmuch-lib.el
+++ b/emacs/notmuch-lib.el
@@ -608,7 +608,7 @@ the given type."
 		       (set-buffer-multibyte nil))
 		     (let ((args `("show" "--format=raw"
 				   ,(format "--part=%s" (plist-get part :id))
-				   ,@(when process-crypto '("--decrypt=true"))
+				   ,@(and process-crypto '("--decrypt=true"))
 				   ,(notmuch-id-to-query (plist-get msg :id))))
 			   (coding-system-for-read
 			    (if binaryp 'no-conversion
@@ -781,8 +781,8 @@ signaled error.  This function does not return."
 	(insert extra)
 	(unless (bolp)
 	  (newline)))))
-  (error "%s" (concat msg (when extra
-			    " (see *Notmuch errors* for more details)"))))
+  (error "%s"
+	 (concat msg (and extra " (see *Notmuch errors* for more details)"))))
 
 (defun notmuch-check-async-exit-status (proc msg &optional command err)
   "If PROC exited abnormally, pop up an error buffer and signal an error.
@@ -836,10 +836,8 @@ You may need to restart Emacs or upgrade your notmuch package."))
 		    (if (integerp exit-status)
 			(format "exit status: %s\n" exit-status)
 		      (format "exit signal: %s\n" exit-status))
-		    (when err
-		      (concat "stderr:\n" err))
-		    (when output
-		      (concat "stdout:\n" output)))))
+		    (and err    (concat "stderr:\n" err))
+		    (and output (concat "stdout:\n" output)))))
       (if err
 	  ;; We have an error message straight from the CLI.
 	  (notmuch-logged-error
@@ -968,8 +966,8 @@ status."
   (let* ((err-file (process-get proc 'err-file))
 	 (err-buffer (or (process-get proc 'err-buffer)
 			 (find-file-noselect err-file)))
-	 (err (when (not (zerop (buffer-size err-buffer)))
-		(with-current-buffer err-buffer (buffer-string))))
+	 (err (and (not (zerop (buffer-size err-buffer)))
+		   (with-current-buffer err-buffer (buffer-string))))
 	 (sub-sentinel (process-get proc 'sub-sentinel))
 	 (real-command (process-get proc 'real-command)))
     (condition-case err
@@ -987,16 +985,17 @@ status."
 	  ;; If that didn't signal an error, then any error output was
 	  ;; really warning output.  Show warnings, if any.
 	  (let ((warnings
-		 (when err
-		   (with-current-buffer err-buffer
-		     (goto-char (point-min))
-		     (end-of-line)
-		     ;; Show first line; stuff remaining lines in the
-		     ;; errors buffer.
-		     (let ((l1 (buffer-substring (point-min) (point))))
-		       (skip-chars-forward "\n")
-		       (cons l1 (unless (eobp)
-				  (buffer-substring (point) (point-max)))))))))
+		 (and err
+		      (with-current-buffer err-buffer
+			(goto-char (point-min))
+			(end-of-line)
+			;; Show first line; stuff remaining lines in the
+			;; errors buffer.
+			(let ((l1 (buffer-substring (point-min) (point))))
+			  (skip-chars-forward "\n")
+			  (cons l1 (and (not (eobp))
+					(buffer-substring (point)
+							  (point-max)))))))))
 	    (when warnings
 	      (notmuch-logged-error (car warnings) (cdr warnings)))))
       (error