I need program this caracters in a stylistic sets in FontLab
Where A must be replaced with A.alt an so on A to Z.

thank you very much for your help

That is beyond the scope of this forum. So let me suggest:

1. Read the FontLab manual, the chapter on writing Feature code, and
2. Visit OpenType Cookbook for more information;
3. After learning the basics, Typophile would be helpful for specific issues.

Best of luck.

First, I'll second the recommendation of the OpenType Cookbook as a reference and guide!

In the OpenType panel....

Your main code in the top right pane will look something like this, only with as many substitutions as you need. (You can also simplify the code here by creating classes, but that's another story.):

feature ss01 {
sub A by A.alt ;
sub B by B.alt ;
} ss01;


In the lower right pane, you'll need languagesystem statements. At a minimum this will be something like the code below. If you support other writing systems, or have language-specific code in your font, it will get more complex (both here and in your code pane):


languagesystem DFLT dflt;
languagesystem latn dflt;