My original definition of the term 'ligature' should perhaps have been more restrictive. The Latin verb ligare means just to bind; and there are surgical ligatures, musical ligatures, etc., etc. My focus was on typographic ligatures; and even they come in two flavors:
1) 'æ' and 'œ' are diphthong ligatures, standard in most Roman-alphabet fonts and having their own assigned code points, SBCS, DBCS, or M[ultiple]BCS; o 'ffl', 'fi' and the like are typesetters' ligatures, usually found only in 'expert' fonts and not having their own code points, probably because needs for them vary from font to font. As I have had occasion to note before, we have good zArchitecture, z/OS and HLASM support for UNICODE availablegto us; and it is time we all started using it, at least in new undertakings. John Gilmore, Ashland, MA 01721 - USA
