Conditional control of display of a property or child in projections

[globallyunique]

The complexity of controlling variations in the display of different combinations of properties or children with just different named projections grows quickly. For example if you have a concept with three children and you want to allow displaying any of them in any combination you need six projections that differ only by the presence or absence of each of the children.

A change that allowed conditional display of a child would eliminate the need for multiple projections. It was suggested in a discussion with Jos on Feb 16 that having a fragment for each child and conditionally displaying it based on a variable or a function call would be possible.