Syntax to mark multiple relationships as unchanged

[zsfre]

in predicates, we end up writing something like:

linked' = linked
working' = working
something' = something

doing this repeatedly is tedious and not always easy to see. I suggest an equivalent to TLA's UNCHANGED

unchanged linked, working, something

[nmacedo]

We are studying language extensions to ease the definition of "events" using predicates, the ability to mark elements as unchanged would be part of that broader extension.

[grayswandyr]

Meanwhile, you can use the "hidden" macro feature of Alloy and define unchanged yourself:

let unchanged[r] { (r) = (r)' }