Remote file name completion

[Michael Albinus]

Hi,

driven by a request on the tramp-devel mailing list, I have
implemented in Tramp 2.1 a slight different behaviour of
`substitute-in-file-name'. It is explained in Tramp's info:

+---
|    Once the remote machine identification is completed, it comes to
| filename completion on the remote host.  This works pretty much like
| for files on the local host, with the exception that minibuffer
| killing via a double-slash works only on the filename part, except
| that filename part starts with `//'.  *Note Minibuffer File:
| (emacs)Minibuffer File.
| 
|    As example, `/telnet:melancholia:/usr/local/bin//etc <TAB>' would
| result in `/telnet:melancholia:/etc', whereas
| `/telnet:melancholia://etc <TAB>' reduces the minibuffer contents to
| `/etc'.  A triple-slash stands for the default behaviour, i.e.
| `/telnet:melancholia:/usr/local/bin///etc <TAB>' expands directly to
| `/etc'.
+---

Quoting the original request:

"If a user is editing a file on a remote host, it is very possible that
 then next file will also be on the remote host. The most natural
 meaning then for / is the root of the remote host."

Shall this behaviour go into the trunk as it is? Or shall it be
customizable by a variable? Personally, I would prefer to make this the
default behaviour for remote filenames, but there might be other
preferences by dayly users.

Best regards, Michael.