When writing expression it would be useful to know, in some cases, whether or not the context is in validation mode or not.
A specific example is when paging in a REST Get Snap: when in validation mode you will get errors about “slot allocation” when the paging exceeds 50 items.
You can put a guard in the “Has next” expression to cut off the paging if the item count is going to exceed 50, but then you have to figure out a way to prevent that guard from interfering when executing the pipeline.
So a simple expression language query would allow you to write something like:
(isValidating() ? (parseInt($.Response['@EndNum']) < 50 : true) && someMethodOfDeterminingHasNext()
OR perhaps there is a better way of accomplishing the same.