> Imagine first a set of strings. This may be merged more easily than the list of lines a dvcs usually deals with but you still get conflicts (I’m not sure what the merge of “add foo” and “add foo; remove foo” should be. It could reasonably be “add foo; remove foo” or a conflict of maybe adding foo)
My imagination is pretty confused by the application of a binary operator with only one argument. Would you please clarify? I think you'll find that when you explicitly think about the unstated arguments the problem makes sense, but I could be misunderstanding your point.
The point, as per the article mentioned in the parent comment, is to talk about merging patches rather than snapshots. This allows you to force certain nice properties of merges like associativity.
Sometimes you need information about deleted things in your patch to be able to merge correctly though I don’t have an example from the top of my head
My imagination is pretty confused by the application of a binary operator with only one argument. Would you please clarify? I think you'll find that when you explicitly think about the unstated arguments the problem makes sense, but I could be misunderstanding your point.