-### IN : $StartMonth, $EndMonth
-### OUT: @Months: array containing all months from $StartMonth to $EndMonth
- my ($StartMonth, $EndMonth) = @_;
- return (undef,undef)
- if ($StartMonth !~ /^\d{4}-\d{2}$/ or $EndMonth !~ /^\d{4}-\d{2}$/);
- # return if $StartMonth = $EndMonth
- return ($StartMonth) if ($StartMonth eq $EndMonth);
+### IN : $MonthExpression ('YYYY-MM' or 'YYYY-MM to YYYY-MM')
+### OUT: @Months: array containing all months from $MonthExpression enumerated
+ my ($MonthExpression )= @_;
+ # return if single month
+ return ($MonthExpression) if ($MonthExpression =~ /^\d{4}-\d{2}$/);
+ # parse $MonthExpression
+ my ($StartMonth, $EndMonth) = split(' to ',$MonthExpression);