Double em-dash in TeX
Jane Austen uses double em-dashes at times. The naive approach I tried in TeX at first— consisting of two consecutive em-dashes—leaves a small but visible amount of whitespace.
A bit of Googling turned up a 1994 comp.text.tex post from Donald Arseneau (who, in addition to being a TeX-nician is also a Tcl'er!) that gave a satisfactory solution:
\mbox{---\kern-1pt---}\penalty\exhyphenpenalty
—Michael A. Cleverly
Sunday, February 03, 2008 at 18:04
In a Unicode-enabled TeX, you can use U+2015 HORIZONTAL BAR, whose alternative name is "quotation dash". This character is frequently used in Western European fiction and in some modern English-language fiction, notably the works of James Joyce.
Sun, 03 Feb 2008, 19:08