Split write permission into append and delete permission

Question

I'm writing a small authorization systems which has read, write, execute, append and delete permissions. If someone can write he can obviously also delete and append, so delete and append are part of write. I think all write operations could be expressed as append and delete and wonder if there would be any reason to distinguish between write and delete+append.

So the question is: Do you know any reason to distinguish between delete+append and write?

Answer 1

I can't think of any. You might want to read up on how different operating systems implement file permissions.

One other thing you might consider is whether write permissions also include read permissions. It might make sense to do so in your case, but you might also consider a case where you want to create a "drop box" where someone can write a file but not be able to subsequently read it.