Formal Definition: The value type is defined by the following
   notation:

     dur-value  = (["+"] / "-") "P" (dur-date / dur-time / dur-week)

     dur-date   = dur-day [dur-time]
     dur-time   = "T" (dur-hour / dur-minute / dur-second)
     dur-week   = 1*DIGIT "W"
     dur-hour   = 1*DIGIT "H" [dur-minute]
     dur-minute = 1*DIGIT "M" [dur-second]
     dur-second = 1*DIGIT "S"
     dur-day    = 1*DIGIT "D"

##</code><code>##

    my @temp = $str =~ m{
            ([\+\-])?   (?# Sign)
            (P)     (?# 'P' for period? This is our magic character)
            (?:
                (?:(\d+)Y)? (?# Years)
                (?:(\d+)M)? (?# Months)
                (?:(\d+)W)? (?# Weeks)
                (?:(\d+)D)? (?# Days)
            )?
            (?:T        (?# Time prefix)
                (?:(\d+)H)? (?# Hours)
                (?:(\d+)M)? (?# Minutes)
                (?:(\d+)S)? (?# Seconds)
            )?
              }x;