I would like to know, besides Modern Standard Arabic as spoken in Egypt, how many distinct Arabic alphabets (I assume each Arabic-speaking country will have its own Arabic alphabet, with a lot of overlap, and a few extra phonological symbols, such as, say, a thaa with four dots above instead of two, or a baa with three dots below to make a p sound) exist?
Can someone please provide me with a list of all such countries (I realize some countries will have a total overlap, whereas others, such as several close to India, perhaps, will have a partial overlap). I would like to have a list of all such countries with their extra symbols.
Furthermore, I would like to know how the Unicode standard accounts for these differences (as far as Arabic is concerned). A list of codes next to the symbols, listed by country though, would be nice.