What have you done with UDAs?

[E.S. Quinn via Digitalmars-d]

On Monday, 22 June 2015 at 19:09:40 UTC, weaselcat wrote:
> I never seem to use them for anything, has anyone else done 
> anything interesting with them?

I use UDAs in my project to generate GTK UI for editing 
components in my ECS. (For things like marking string fields as 
filenames, or giving numeric fields upper and lower bounds)

https://dl.dropboxusercontent.com/u/187059/Screenshot-sarah%20-%20Entity%20Editor.png