piem-lei-show: Let caller suppress displaying buffer

piem-lei-show switches to the message buffer with pop-to-buffer, but
that behavior won't work well in the context of a mode that gives an
overview of lei-q search results.  In that case, a wrapper command
will want to control the display of the buffer so that it can keep a
split window layout and avoid switching to the piem-lei-show-mode
buffer.

And more generally, Lisp callers are likely to want to handle the
display themselves.  Add an optional 'display' parameter that defaults
to nil for non-interactive calls.

Message-Id: <20210605211402.20304-3-kyle@kyleam.com>

1 files changed, 9 insertions, 4 deletions

diff --git a/piem-lei.el b/piem-lei.el
index 5b986fc..fe6ab79 100644
--- a/piem-lei.el
+++ b/piem-lei.el
@@ -30,10 +30,13 @@
 
 ;;;; Message display
 
-(defun piem-lei-show (mid)
-  "Show message for MID."
+(defun piem-lei-show (mid &optional display)
+  "Show message for MID.
+When called non-interactively, return the buffer but do not display it
+unless DISPLAY is non-nil."
   (interactive
-   (list (read-string "Message ID: " nil nil (piem-mid))))
+   (list (read-string "Message ID: " nil nil (piem-mid))
+         'display))
   (with-current-buffer (get-buffer-create "*lei-show*")
     (let ((inhibit-read-only t))
       (erase-buffer)
@@ -44,7 +47,9 @@
         (delete-region (line-beginning-position)
                        (1+ (line-end-position))))
       (piem-lei-show-mode))
-    (pop-to-buffer (current-buffer))))
+    (if display
+        (pop-to-buffer (current-buffer))
+      (current-buffer))))
 
 (define-derived-mode piem-lei-show-mode special-mode "lei-show"
   "Major mode for displaying message via lei."