I don't know about you, dear hates-software reader, but, in general, when wanting to write something like an index for a search engine I have two major uses cases.
The first is - open the index and start using it. The second is - open the index, if it doesn't exists then create it, then use it. The number of times I want to open the index and nuke any existing comments is small. Even whilst developing a search engine. Still, I can imagine it being useful to, you know, someone. Lucene, the Java based search engine with the hateful documentation, seems to think that it is important. Very important. Because it doesn't have a "Create if it doesn't exist mode". I know not why. Sure it's emulatable in my own code. But so would throwing an error if it didn't exist. Or deleting all the documents if it did exist. When you've had 3 hours sleep these things can trip you up and suddenly all your indexed data is gone. All of it. I hate you Lucene. I'm giving you cancer with my thumbs.
