I am differentiating em-dashes (—) from hypens (-) in emacs using this code in my .emacs:
(let* ((glyph-em-dash (make-glyph-code ?\u002D 'font-lock-function-name-face)) ) (aset standard-display-table 8212 `[,glyph-em-dash ,glyph-em-dash ,glyph-em-dash]))
The issue is that emacs counts these characters as taking up three columns (which they do visually). How can I tell emacs to count the em-dash as only one character when calculating line lengths, etc.?