Re: [PATCH 3/4] auxdisplay: charlcd: fix x/y address commands

[Robert Abel]

Hi Willy,

On 27 Feb 2018 06:19, Willy Tarreau wrote:
> Well actually I don't see a problem there at all. The principle is simply
> to accept any sequence assigning x or y or both. If you write x4y2x6, it
> simply means that you changed your mind regarding x and that the last
> value (6) is the one you want. Just as if you wrote "^[[Lx4;^[[y2;^[[x6;".
> The while loop doesn't even try to do anything clever, it simply parses
> everything matching x and y followed by digits. I think the only reason
> for having both x and y processed in the same loop was to call
> charlcd_gotoxy() only once for both axes.

I didn't say it is a problem. It is however an edge case that incurs a
lot of code for little to no functionality.
I'd much prefer if we broke backwards compatibility here and actually
only parse the format that is indicated in the comment:

>         case 'x':       /* gotoxy : LxXXX[yYYY]; */
>         case 'y':       /* gotoxy : LyYYY[xXXX]; */
>  

Exactly one x command followed exactly by zero or one y command or
vice-versa.

If somebody changes their mind during the escape sequence, they can just
issue a new one instead of appending to the current one.

I'll post an example patch.

Regards,

Robert