DOTFILL,
/// rubber length, filled with a rule
HRULEFILL,
+ /// rubber length, filled with a left arrow
+ LEFTARROWFILL,
+ /// rubber length, filled with a right arrow
+ RIGHTARROWFILL,
+ // rubber length, filled with an up brace
+ UPBRACEFILL,
+ // rubber length, filled with a down brace
+ DOWNBRACEFILL,
/// \hspace{length}
CUSTOM,
/// \hspace*{length}