Last modified: 2010-05-15 15:38:13 UTC
The proper way to enter dashes--using a typewriter--is a double-hyphen without spaces. The resulting proper typesetting would be an em dash with no space (or a hair space) around it--not full spaces. The current feature (from bug 1485) doesn't substitute "--" with an em dash, meaning that the most common typewriter-like entry of these dashes is not substituted; and further, the substitution of " -- " encourages the use of this construct, which is unusual, and which results in incorrect typography (full spaces around the resulting em dash).
I've removed the automatic dash conversion for now; perhaps in some future parser that actually works in a clean fashion this can be done without breaking other markup left and right.