Given a list of dates
12/07/2010
13/07/2010
14/07/2010
15/07/2010
12/08/2010
13/08/2010
14/08/2010
15/08/2010
19/08/2010
20/08/2010
21/08/2010
I'm looking for pointers towards a recursive pseudocode algorithm (which I can translate into a FileMaker custom function) for producing a list of ranges, i.e.
12/07/2010 to 15/07/2010, 12/08/2010 to 15/08/2010, 19/08/2010 to 20/08/2010
The list is presorted and de-deuplicated. I've tried starting from both the first value and working forwards, and the last value and working backwards but I just can't seem to get it to work. Having one of those frustrating days... It would be nice if the signature was something like
CollapseDateList( dateList, separator, ellipsis )
:-)