describing a complex data types with Magritte

Hello list, I'm trying to describe a model, which values could have complex or multiple types at once. In general , a question is how to provide a description of following fields: suppose you have a field, which in own turn having own fields, and you want to display them in-line i.e. position :: point(x,y) point::x = integer point::y = integer so i'd like to describe a position, as a compound data type, lets say, instances of class Point which having own fields (x,y). So, then in form i could have this field displayed like following: position x: [ ... ] y: [ ...] Another case, is when value can use multiple types. Following previous example, for position, now i reconsidered and want a position accept not only instances of Point, but instances of Point3D as well. So, then Magritte should be able to display my 'position' field editor like following: position * x: [ ... ] y: [ ...] * x: [ ... ] y: [ ...] z: [...] where * is radio button. Or there can be different view where user can select a type first, and then edit value: position [<type selection combobox>] [ value editor for selected type ] I don't want to get into detail how to render/build such editors, my main question, is how to describe such things in less painfull/controversial way using Magritte. -- Best regards, Igor Stasenko AKA sig.