p4lang
Side effects in select expressionList
By select expressionList, I mean the expression list e1, e2, ... in transition select (e1, e2, ...) { .... }.
If we follow the clarification in the spec made with PR #834, then side effects should be explicitly allowed in the expression list e1, e2, ..., and all side effects of e(i) should take effect before e(I+1) begins evaluation.
Otherwise, we could consider instead disallowing side effects in these expressions, as was proposed in PR #831
I do not believe there is any urgency to resolve this before spec version 1.2.1 is released, if we want to bring it up in a LDWG meeting before deciding which way this should go.
I thought all lists/arguments are evaluated left to right? I was going to treat it like a list so it just works correctly.
Adding this makes sense:
The `expressionList` just like a `{}` list is evaluated from left to right prior to the invocation of the select itself.
Right after:
In a `select` expression, if the `expressionList` has type `tuple<T>`,
then each `keysetExpression` must have type `set<tuple<T>>`.
This is just like all other expressions and all.
In the interest of tidying up the set of active issues on the P4 specification repository, I'm marking this as "stalled" and closing it. Of course, we can always re-open it in the future if there is interest in resurrecting it.
