Re: Feedback on ForStatement

How does one distinguish between an absent value and a value of null (e.g.,
as a list element)?

Christopher Smith

On Fri, Feb 6, 2026, 10:12 Milles, Eric (TR Technology) via dev <
dev-GSC0n/0aZo1d/SJB6HiN2Ni2O/[email protected]> wrote:

> I tried to make minimal changes when adding index variable to
> ForStatement.  It seemed that getValueVariable() and getIndexVariable() was
> the cleanest extension of getVariable() (now deprecated).  One option
> versus adding a constructor would be to add a "forS" factory overload to
> GeneralUtils that supports classical "for (int i = 0; i < n; ++i) ..."
>  without making reference to the dummy variable.
>
> A bolder approach would be to separate "for (x in y)" from "for (int i =
> 0; i < n; ++i)" as distinct statement classes.  Maybe they extend from
> ForStatement to keep visitors happy.
>
>
> When getIndexVariable() and getValueVariable() were introduced, I designed
> them so you could use them equally.  That is, they return null when no
> index or value variable was given.  To that end, I would not want to see
> hasValueVariable() and hasIndexVariable() introduced.  You should be able
> to do any "if (hasValueVariable()) f(getValueVaruable())" with
> "Optional.ofNullable(getValueVaruable()).ifPresent(v -> f(v))" or of course
> "var v = getValueVariable(); if (v != null) f(v);".
>
> In summary, I'd favor a light tough for a refactoring; add as little as
> possible to the statement class.  Unless you are willing to separate the
> abstractions of collection and counting loops.
>
> Eric M.
>