Checkerboard background colours

Checkerboard background colours

[Jeffrey Ratcliffe]

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I'm trying to write a major mode for a data language that uses fixed
field widths. In order to highlight the fields, I'd like to change the
background colour so that adjacent fields do not have the same
background colour, creating a checkerboard effect.

How can I achieve this?

Please cc me as I am not subscribed.

Regards

Jeff

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Re: Checkerboard background colours

[Lennart Borgman]

On Mon, Feb 22, 2010 at 5:42 PM, Jeffrey Ratcliffe
<jeffrey.ratcliffe@gmail.com> wrote:
> I'm trying to write a major mode for a data language that uses fixed
> field widths. In order to highlight the fields, I'd like to change the
> background colour so that adjacent fields do not have the same
> background colour, creating a checkerboard effect.
>
> How can I achieve this?
>
> Please cc me as I am not subscribed.


See for example ocr-user.el in nXhtml.

Re: Checkerboard background colours

[Jeffrey Ratcliffe]

On 22 February 2010 22:13, Lennart Borgman <lennart.borgman@gmail.com> wrote:
> See for example ocr-user.el in nXhtml.

Thanks for the tip. This works fine in emacs 23, but not on 21.4,
where it gives the error "invalid regular expression".

Do you have any idea how to get this working in 21.4? font-lock itself
seems to work OK, it really does seem to be a problem with the regex.

Please cc me on replies, as I am not subscribed.

Regards

Jeff

Re: Checkerboard background colours

[Jeffrey Ratcliffe]

On 23 July 2010 13:28, Jeffrey Ratcliffe <jeffrey.ratcliffe@gmail.com> wrote:
> Do you have any idea how to get this working in 21.4? font-lock itself
> seems to work OK, it really does seem to be a problem with the regex.

On removing the shy groups, the regex error disappeared under 21.4.
The highlighting still didn't work. I simplified it to the following,
which does:

(defvar my-keywords
 '(
   ("\\([\-+0-9a-zA-Z \.]\\{1,8\\}\\)\\([\-+0-9a-zA-Z \.]\\{1,8\\}\\)?"
                          1 '(:background "LightBlue1"))
  )
)

How can get this only to be active on lines between "BEGIN DATA" and "END DATA"?

Please cc me on replies, as I am not subscribed.

Regards

Jeff