Introduce convencience function for site prompting

Arose from comment discussion at [1].  This function allows for
simplified syntax when the use case wants to retrieve a site token in an
interactive context.  See docstring for details.

[1]: https://github.com/vermiculus/sx.el/pull/183/files#r22403919

2 files changed, 13 insertions, 1 deletions

diff --git a/sx-interaction.el b/sx-interaction.el
index 9ced1ab..d814485 100644
--- a/sx-interaction.el
+++ b/sx-interaction.el
@@ -345,6 +345,18 @@ from context at point."
      (sx-site-get-api-tokens) nil t nil nil
      default)))
 
+(defun sx--maybe-site-prompt (arg)
+  "Get a site token conditionally in an interactive context.
+If PREFIX-ARG is non-nil, use `sx--interactive-site-prompt'.
+Otherwise, use `sx-question-list--site' if non-nil.  If nil,
+use `sx--interactive-site-prompt' anyway."
+  ;; This could eventually be generalized into (sx--maybe-prompt
+  ;; prefix-arg value-if-non-nil #'prompt-function).
+  (if arg
+      (sx--interactive-site-prompt)
+    (or sx-question-list--site
+        (sx--interactive-site-prompt))))
+
 ;;;###autoload
 (defun sx-ask (site)
   "Start composing a question for SITE.
diff --git a/sx-search.el b/sx-search.el
index 928db5d..2633da9 100644
--- a/sx-search.el
+++ b/sx-search.el
@@ -74,7 +74,7 @@ of which is allowed to match.
 Interactively, the user is asked for SITE and QUERY.  With a
 prefix argument, the user is asked for everything."
   (interactive
-   (let ((site (sx--interactive-site-prompt))
+   (let ((site (sx--maybe-site-prompt current-prefix-arg))
          (query (read-string
                  (format "Query (%s): "
                    (if current-prefix-arg "optional" "mandatory"))