Saluton!
In the following statement vim does not identify the regular
expression /^9+/ while it correctly gets /^9([0-9]+)/ (that are
regular expressions to match COBOL style format specifiers like 9(6)
or 999999.
Insert a linebreak in front of /^9+/ makes identification work 
@i = (format =~ /^9([0-9]+)/) ? $~[0][2…-1].to_i : /^9+/.match(format)[0].length
Gis,
Josef ‘Jupp’ Schugt