After my App Store review, the developer encouraged me to come to the forums to provide feedback on this issue. He asked these questions:
Q) Should there be a way for a user to differentiate between the current search mode and the new one that searches for each term individually – or should the app do both modes automatically?
A) The search box should handle both forms automatically. Search currently only works if your terms are adjacent to each other. But we want it to work for two terms that may be in the same entry, but not in the same sentence or even paragraph. So in the new search field, terms that are adjacent (if there are any) can surface as most relevant up top. The farther apart the terms are in an entry, or the older an entry is, the further down it can be in the results list. Also, I’d posit that search is so important that the search box should be visible in the top bar of the Mac app all the time, no matter what view you’re in.
Q) How should the terms be separated in the search box and how to force the app to treat multiple words as one term instead of individual terms? Can you give an example on what you tried to search for that Diarium wasn't able to find?
A) For instance, if I’m trying to find the entry for a specific day. I know I went to a town named Murphy on that day, but I go to a town named Murphy several days a week. And I know I also worked on cataloguing contra dances that day. Right now, if I search the term “murphy contra” the app should be able to figure out which entries include both of those words. But instead, no results appear at all, despite my being able to confirm that each of those words is in the entry I was looking for.