[Gnu-arch-users] Re: tagline robustness

[Juri Linkov]

I suggest that it could be better and safer if arch tag had a form
similar to RCS tag ($Id$, $Header$, etc.).  Even though RCS tags
have different purposes, their format should be taken by arch tags.
In this case arch tags will look like:

   For a C file:

     /* $Arch: 53bb84c6-dee0-46c6-a275-2db144993d89$ */
   or
     static char archid[] = "$Arch: 53bb84c6-dee0-46c6-a275-2db144993d89$";

There are numerous advantages:

1. This format is less error-prone.  It explicitly separates
the value of arch tag from the rest of the file: all text
inside the $ characters is considered as arch tag value, so there is
no need to use different comment delimiters or newline for this.
It makes arch tags less fragile to its textual context where it is used,
and solves the problem of spaces inside the tag (allows all symbols but $)

2. $Arch$ format makes it easier to detect arch tags in source files,
because this format make tags more unambiguous.  What is needed
is to scan the whole file for the "$Arch:" string.  So arch tags
could be embedded not only in comments but also in literal strings.

3. $Arch$ tag can be placed everywhere in the file, not only in
the first and last 1024-byte blocks of the file.  RCS tags
already can be placed everywhere and have no problems with this.

4. It make possible to manually insert empty $Arch$ tag as a placeholder
into file, and assign an unique ID automatically by external tools.

5. Format of RCS tags is already familiar to the most people,
so there is no need in special warning ("Do not change this comment"),
because users already know that everything inside the $ characters
shouldn't be changed manually.

-- 
http://www.jurta.org/emacs/