Re: [PATCH] docs: fix minor glitch in illustration

[Jeff King <peff@peff.net>]

On Tue, Apr 21, 2020 at 05:35:04PM +0000, Michael F. Schönitzer via GitGitGadget wrote:

> In the example by Jon Loeliger the selector 'A^2' was duplicated. This
> might confuse readers.
> 
> Signed-off-by: Michael F. Schönitzer <michael@schoenitzer.de>
> ---
>     fix minor glitch in an illustration in the documentation
>     
>     In the example by Jon Loeliger the selector 'A^2' was duplicated. Since
>     it is the only duplicate and doesn't fix in the structure I assume it is
>     there by incident and since it can confuse readers this patch removes
>     it.

This extra explanation could probably go into the commit message. :)

> diff --git a/Documentation/revisions.txt b/Documentation/revisions.txt
> index 97f995e5a9a..1ad95065c1f 100644
> --- a/Documentation/revisions.txt
> +++ b/Documentation/revisions.txt
> @@ -233,7 +233,7 @@ G   H   I   J
>  
>      A =      = A^0
>      B = A^   = A^1     = A~1
> -    C = A^2  = A^2
> +    C =      = A^2
>      D = A^^  = A^1^1   = A~2

OK, so this is describing this diagram:

     D   E   F
      \  |  / \
       \ | /   |
        \|/    |
         B     C
          \   /
           \ /
            A

For "B" we can express A^ as a shorthand for A^1. But for C, a second
parent, there is no such shorthand. We _must_ say A^2. But there's not
much point in saying it twice.

We could just say "C = A^2", but it makes sense to keep A^2 aligned with
the A^1 from the "B" line to make the comparison obvious.

So this patch makes sense to me.

>      E = B^2  = A^^2

Curiously E goes right for B^2. It could be:

  E =    = B^2 = A^^2

or something if we really wanted to make a giant table where all the
possible names were grouped, but I don't think there's much point in
doing so.

-Peff