+(defun notmuch-show--build-queries (thread context)
+ "Return a list of queries to try for this search.
+
+THREAD and CONTEXT are both strings, though CONTEXT may be nil.
+When CONTEXT is not nil, the first query is the conjunction of it
+and THREAD. The next query is THREAD alone, and serves as a
+fallback if the prior matches no messages."
+ (let (queries)
+ (push (list thread) queries)
+ (if context (push (list thread "and (" context ")") queries))
+ queries))
+