Whereas we find three different madda signs in South Asian editions of the qurʾān,
in Ottoman editions there is only one sign,
but it is twice as long as the usual madda sign and it belongs to a different mark class: it is above normal marks.
In modern typeset editions it sits above the consonant and its harakat streching over the following letter of elongation (vowel letter)
-- in mss. it sometimes sits before the alif "because" there is not enough space above the letter of elongation (either because the line are not high enough or because of a letter like kaf).
Should it "belong" to the first letter and extend over the second?
Should it always "belong" to the consonant of the enlongated syllable irrespective of its actual position in the ms?
This "madd above two letters" occurs in Persian editions as well:
In older Persian editions we find a ligature of two madda signs:
In a modern Turkish edition we find this:
Unlike the elongated fatha that is just a glyph variant above elongated or swash letters,
the long madda sign is a different character, different from the normal madda sign that is.
I want to conclude with a warning. Not everything one finds in a ms. is correct.
On the following page al-ʿalāmīn is written with madda. Although this is a scribal error for a long fatha, one should be free to reproduce this mistake on the computer when one is writing about this particular manuscript.
On the other hand in Unicode there is one Koranic madda char encoded that should not be there:
small madda is just a glyph variant when madda sits above a small letter (mall alif, small yeh, small waw).
Could one use that could point of one of the needed Koranic madda signs? ??