On 2017-05-28 12:28, Eli Zaretskii wrote: >> Cc: 27103@debbugs.gnu.org >> From: Clément Pit--Claudel >> Date: Sat, 27 May 2017 15:52:27 -0400 >> >> Would the same caveat apply to the creation of a new 'left-fringe text property, such that instead of (concat "A" (propertize "_" 'display '(left-fringe filled-square))) one could write (propertize "A" 'left-fringe 'filled-square)? > > I'm not sure I understand why the former uses 'concat', while the > latter doesn't. So perhaps I'm missing the point, because otherwise > this looks like just "syntactic sugar", is it? It uses `concat' because the display spec is replacing. Let me try a better example :) Consider a buffer with contents like this: (defun … …) (defun … …) Suppose I want to highlight each defun with a fringe indicator. With my proposal, one could use the following font-lock rule: ("^(defun" (0 '(face nil left-fringe right-arrow))) And the contents of the buffer would look like this: → (defun … …) → (defun … …) I don't think such a result is currently achievable without overlays (which are not nearly fast enough for my purposes). Cheers, Clément.