Ditto Date Filter
The DateFilter extender (&extenders=`dateFilter`) enables you to filter Ditto listing by year, month and day in a specified document field or template variable. The Ditto site describes it as a "filtering companion to Reflect or other date based filtering", which I think means you can use a Reflect archive listing to feed back the date parameters. Maybe I'll go into Reflect later. Meanwhile, DateFilter is quite easy to use directly with Ditto.
The &dateFilterSource parameter can be `get`, `params` or the name of a request variable. The default is `get` (obtain filter data from URL query string). Using `params`, you can set the filter in the Ditto call, e.g. &dateFilterSource=`params` &year=`2007`. Using the other option, a request variable passed in the URL query string or the POST data from a form, the date is given in a single string that can be interpreted by the PHP strtotime() function and broken down into a specific year, month and day, e.g. &dateFilterSource=`cdate` and www.example.com/blogs.html?cdate=aug+4+2007 (substituting plus signs for spaces as it's in a URL).
The &dateSource parameter determines which field or template variable is used for comparison in filtering, as well as being the source for the [+date+] placeholder.
The &year, &month (numerical value) and &day parameters set the date to filter on in a hierarchical way - a month without a year, or a day without a month, will be ignored.
There is also a &dateFilterDefault parameter, which can be set to `0` (off), `1` (current year), `2` (current month) or `3` (current day).
The extender sets the placeholders [+year+] [+month+] and [+day+], which can be used in headings on the listing page.
Items for June 2006
(Heading code: <h4>Items for [+day+] [+month+] [+year+]</h4>