[texhax] automating colortbl?

[Yuri Robbers]

Hello,

for a book I am working on, I use a lot of tables in which I use the
colortbl package to colour some rows (three rows uncoloured, three rows
with light grey background, etc.) in order to improve visibility.

My problem is, that if I enter an extra entry in a table later, I will
have to re-adjust all the \rowcolor{0.9}{gray} commands to fit my "three
white - three grey" scheme. This seems to go rather against the general
TeX spirit.

Alternatively, I could wait till the whole book is finished, and
manually go over hundreds of tables, inserting all the
\rowcolor{0.9}{gray}'s by hand, possibly using some emacs macros to
lighten my task, but that would mean that the draft versions cannot have
the grey backgrounds.

Does anyone know of a way to automate this whole procedure? Perhaps by
creating a new environment...

I now use regular tabular environments, as well as longtable. I also use
the booktabs package. 

Kind regards,
Yuri Robbers.