For v0.7+

Use fieldnames(x), where x is a DataType. For example, use fieldnames(Date), instead of fieldnames(today()), or else use fieldnames(typeof(today())).

This returns Vector{Symbol} listing the field names in order.

If a field name is myfield, then to retrieve the values in that field use either getfield(x, :myfield), or the shortcut syntax x.myfield.

Another useful and related function to play around with is dump(x).

Before v0.7

Use fieldnames(x), where x is either an instance of the composite type you are interested in, or else a DataType. That is, fieldnames(today()) and fieldnames(Date) are equally valid and have the same output.