Re: [O] New feature? Remove duplicate subheadings, preserving order

[Florian Beck]

> AFAIK, this is the first time this need is expressed on this ML. There
> is no equivalent in "org-list.el" either.

A way to handle duplicates would be useful, indeed. But a basic function 
should only remove duplicates that are truly identical (same properties, 
same tags, same/no content). Still, removing true duplicates from 
subtrees (AND lists) would be useful.

More useful would be a slightly more general approach. I have three 
kinds of duplicates:
 - duplicate IDs (which are handled rather poorly),
 - duplicate content (which often is only almost identical) and
 - duplicate headings (which usually I want to rectify when they are on
   the same level of the same subtree)

As you can see, a fixed concept of duplication is probably not going to 
work.

What I'd like is a function finds duplicates according to scope, match 
(as in `org-map-entries') and a user defined function. This function 
should then display the problem cases (via agenda view?). Then we need a 
couple of convenience functions like
 - delete all duplicates but the one at point,
 - mark duplicates I want to keep,
 - uniquify entries (tricky; for headlines maybe prompt the user; for
   IDs, we should check if the ID is referenced from somewhere)
 - merge entries.

But then, I also have duplicates (in content) I want to keep, e.g. one 
in my notes and in a writing project. So, we'd need a property like 
"DUPLICATE_OF".