I have an application that needs to deal with floating time, UTC and local time. I can use ptime to represent floating and UTC but there's then no way to tell, for a given ptime instance, whether it represents a floating time or UTC. I could use local_time with a null tz to represent UTC or floating (seems like a hack and still only allows me one or the other representation) and a non-null tz for local times. Given only two 'time' classes (ptime and local_time) what's the best way to represent three different time concepts? Should I inherit from local_time to give me my three representations? -- Mike Higginbottom Paul Smith Computer Services Silk Mill House 196 Huddersfield Road Meltham Holmfirth HD9 4AW United Kingdom http://www.pscs.co.uk +44 (0)1484 855800