Here is a Clojure library to produce iCalendar objects, as defined by RFC 2445.

=> (use 'clj-ical.format)

Create a VCALENDAR with some VEVENTS

=> (write-object 
     [:vcalendar 
       [:vevent 
         [:summary "Bastille Day Party"]]])

will produce

BEGIN:VCALENDAR
BEGIN:VEVENT
SUMMARY:Bastille Day Party
END:VEVENT
END:VCALENDAR

The library correctly obeys all requirements of the RFC 2445 specification, such as

• long-line folding
• property parameters
• CRLF line termination