I've got a lot less to write since everybody else got there first. Christoph Päper <christoph dot paeper at tu dash clausthal dot de> wrote:
> I recently learned in <news:de.etc.sprache.deutsch> that there has > been a tradition (in handwritten text more than in print) of writing > "mm" as only one "m" with a macron above. I can't find any such > character in Unicode, just U+1E3F and U+1E41. Assuming that you want to encode the m-macron directly--rather than encoding "mm" and letting a German-handwriting-specific rendering system convert this to m-macron, as Ken suggested--the correct solution would be to use a combining sequence, "m" followed by U+0304 COMBINING MACRON. I suppose you could use U+0305 COMBINING OVERLINE instead, but the decision of which mark to use should be based on whether the mark really is a macron or an overline, not on the width of the glyph. U+0304 already has to adjust its width depending on whether it appears over an "i" or an "a". > You could of course build something similar with "m"+U+0305 to > resemble the look, but that won't become "mm" (just "m" or "m¯") after > a conversion to e.g. ISO-8859-1. Two important points here. First, a combining sequence doesn't simply "resemble the look" of a precomposed character; it is *completely equivalent* to the precomposed character. If you wanted to represent an "a" with macron, which does exist in a precomposed form, you would be just as correct using either U+0101 or a combination of U+0061 and U+0304 (though normalization might require you to choose one or the other; see Unicode Standard Annex #15). Second, no Unicode character that is not already in (e.g.) ISO 8859-1 is ever "automatically" converted to an 8859-1 character. You will always have to have some explicit mapping table or logic to perform such a conversion. This is just as true for a precomposed character as it is for a combining sequence. If you wanted to build a conversion layer to convert between "m̄" and "mm" you could certainly do so. -Doug Ewell Fullerton, California
