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NAME

       Format of URLs - The given URLs are ’overlayed’ according to their
       priority, and they get a name (to ease updating only parts).

       Such an extended URL has the form

          [’name:’{name},][’target:’{t-rev},][’prio:’{prio},]URL

        where URL is a standard URL known by subversion -- something like
       http://...., svn://... or svn+ssh://....

       The arguments before the URL are optional and can be in any order; the
       URL must be last.

       Example:

          name:perl,prio:5,svn://...

        or, using abbreviations,

          N:perl,P:5,T:324,svn://...

       Please mind that the full syntax is in lower case, whereas the
       abbreviations are capitalized!
        Internally the : is looked for, and if the part before this character
       is a known keyword, it is used.
        As soon as we find an unknown keyword we treat it as an URL, ie. stop
       processing.

       The priority is in reverse numeric order - the lower the number, the
       higher the priority. (See url__current_has_precedence() )

Why a priority?

       When we have to overlay several URLs, we have to know which URL takes
       precedence - in case the same entry is in more than one. (Which is not
       recommended!)

Why a name?

       We need a name, so that the user can say ’<b>commit all outstanding
       changes to the repository at URL x</b>’, without having to remember the
       full URL. After all, this URL should already be known, as there’s a
       list of URLs to update from.

       You should only use alphanumeric characters and the underscore here;
       or, in other words, \w or [a-zA-Z0-9_]. (Whitespace, comma and
       semicolon get used as separators.)

What can I do with the target revision?

       Using the target revision you can tell fsvs that it should use the
       given revision number as destination revision - so update would go
       there, but not further. Please note that the given revision number
       overrides the -r parameter; this sets the destination for all URLs.

       The default target is HEAD.

       Note:
           In subversion you can enter URL@revision - this syntax may be
           implemented in fsvs too. (But it has the problem, that as soon as
           you have a @ in the URL, you must give the target revision
           everytime!)

Theres an additional internal number - why that?
       This internal number is not for use by the user. It is just used to
       have an unique identifier for an URL, without using the full string.

       Note:
           On my system the package names are on average 12.3 characters long
           (1024 packages with 12629 bytes, including newline):

              COLUMNS=200 dpkg-query -l | cut -c5- | cut -f1 -d’ ’ | wc

       So if we store an id of the url instead of the name, we have approx. 4
       bytes per entry (length of strings of numbers from 1 to 1024). Whereas
       we’d now use 12.3 characters, that’s a difference of 8.3 per entry.

       Multiplied with 150 000 entries we get about 1MB difference in filesize
       of the dir-file. Not really small ...

       Currently we use about 92 bytes per entry. So we’d (unnecessarily)
       increase the size by about 10%.

       That’s why there’s an url_t::internal_number.