Commit 298a0281f (http://git.savannah.gnu.org/cgit/groff.git/commit/?id=298a0281f) modified how the em dash is displayed on UTF-8 terminals. I have reservations about this change and want to get other opinions.
The change applies only to UTF-8 output, the only terminal encoding that includes an em dash character. The behavior on all other output encodings remains the same, changing the em dash to "--". This is the longstanding typewriter convention for the em dash, and remains the best option for character sets that lack the character. The new logic is this: .ie '\?\*[.T]\?'\?utf8\?' .char \[em] \[em]\[em] .el .char \[em] -- The motivation is given in the commit log: making \[em] look "more like a true em dash, taking up two character cells." I'm sympathetic to the aesthetic concern. An em dash in any monospace font is hard to distinguish from a hyphen and other dash-like glyphs. My first concern is that this motivation is communicated only in the commit log, leaving a bit of a head-scratcher to anyone merely reading the code. If this logic is kept, its motive should be commented in the code. My larger concern, though, is with keeping this substitution at all. Two em dashes in a row is part of no typographic convention. This will paste very poorly into any text field that uses a proportional font. It interferes with greps and other searches: most readers seeing two hyphen-like characters in a row in a monospace font will conclude that they are in fact two hyphens, the longstanding convention, rather than two em dashes. It will (rightfully) get flagged as an error by any software that does grammar and punctuation checking. (Admittedly, such software is probably rarely deployed on terminal output.) My instinct is that these concerns outweigh the aesthetic benefit of the substitution on the screen. But even if the aesthetic concern in monospace-land is given more weight, two em dashes in a row is a less preferable substitution than the longstanding convention of two hyphens. Visually, they'll look nearly the same, but the two hyphens will have fewer of the drawbacks of two em dashes. Opinions (concurring and opposing) wanted.
