Meeting 2007-12-12 included discussion over possible characters to mark:
  - current line
  - breakpoint
  - executable statement
there was consensus on one "->" vis:
  ->1234     current_line();
as a way to denote the current line.  From there several suggestions were made vis:
   *1234     a_breakpoint();
   >1234     a_breakpoint();
   b1234     a_breakpoint();
and:
   |1235     an_executable_statement();
   *1234     an_executable_statement();
   >1236     an_executable_statement();