texttools and standard library packages

[agent@drrob1.com]

I am a total newbie in regards to Ada, but have been using stony brook
modula2 for many years.

I am trying to use the source texttools-2-1-0 and to compile the
ttdemo program.  I am getting an error saying that To255 is undefined.
I cannot find where this is.

Where do I look, or what library to I have to import (with,use)?

Also, it would be very helpful for me to have a listing of all
packages and procedures/functions in all the included libraries. Where
would I find such a list that is easily searchable?

Thanks