Newline = \n;
Decimal = [0-9]+ ( "." [0-9]* );

VEvent = <event =
         "BEGIN:EVENT"                                         ${Newline}
         (
           "SUMMARY:" <summary = .* - (.* ${Newline} .*) >     ${Newline}
            <>
           "START:"   <start   = .* - (.* ${Newline} .*) >     ${Newline}
            <>
           "END:"     <end     = .* - (.* ${Newline} .*) >     ${Newline}
         )
         "END:EVENT"                                           ${Newline}
         >;

ICalendar = <cal =
        "BEGIN:CALENDAR"                                       ${Newline}
        "VERSION:"    <version = ${Decimal} >                  ${Newline}
        "PRODID:"     <prodid  = .* - (.*  ${Newline} .*) >    ${Newline}
           ${VEvent}*
        "END:CALENDAR"                                         ${Newline}
        >;

/**
Example:

BEGIN:CALENDAR
VERSION:2.0
PRODID:-//hacksw/handcal
BEGIN:EVENT
DTSTART:19920626T201500Z
DTEND:19920626T220000Z
SUMMARY:The European Championship final
END:EVENT
END:CALENDAR
**/