I think I explained poorly.
If I use:
(getvar "CLAYER") "Abcd")
and the layer name is all in caps (ABCD) I have to make another line
(getvar "CLAYER") "ABCD")
in order to get both of them.
But if there is another situation, aBcd, I have to add another line.
That's why I tried to ignore or clean the casing for the result of getvar "CLAYER". Or to find another method.