If you can have arbitrary code inside a "with" block, without any
qualification for the members, then I'd imagine it'd be practically
useless with templates (i.e., when the object is type dependent), for
the same reason you can't use members of dependent bases without some
sort of qualification.

On 3/22/25 08:55, Vaibhav Parate via Std-Proposals wrote:
> Hello,
> Before I spend time on a formal paper for this idea, I want some
> feedback and suggestions.
>
> *Idea:*
> I'd like to propose a *with* block for C++ that allows extending the
> scope of objects, making field access easier and reducing redundant
> qualifiers.
>
> *Motivation (while working on some personal projects):*
> Currently, in C++, working with objects often requires repeatedly
> qualifying fields with *object->* or *object.* inside functions and
> lambdas. This leads to unnecessary verbosity, especially when dealing
> with deeply nested structures.
>
> *Example:*
> /C++ Currently (It is readable but very quickly gets messy, specially
> when you are the author of the entire codebase):/
> void foo (A a, B* b, C& c) { // let's assume A, B, and C are types
>
> a.doSomething();
>
> b->doSomethingElse();
> // some other calles
> c.trySomethingElse();
>
> }
>
> /C++ with "*with*" blocks:/
> void foo (A a, B* b, C& c) {
>
> with (a, *b, c) {
>
> doSomething();
>
> doSomethingElse();
> // some other calles
> trySomethingElse();
>
> }
>
> }
>
> /Or if you want to use them for the entire function? Consider this:/
> void foo (A a, B* b, C& c) with (a, *b, c) {
>
> doSomething();
> doSomethingElse();
> // some other calles
> trySomethingElse();
>
> }
>
> *What about field name collisions?*
> They can be easily solved using existing syntax of
> using *object.* or *object->*.
>
> *Maybe it will be harder for people to port old code that uses "with" as
> an identifier (variable name etc.) what about that?*
> It's not necessary to use this exact keyword, it can be something else
> like "*using*" which is already a keyword.
>
> *Why?*
> I always find it annoying to use qualifiers while initializing objects,
> yeah there are constructors (and other initializers), but there are
> sometimes where constructors aren't enough and the object needs to be
> initialized in different ways. I may be wrong here and maybe the only
> one facing these issues, but does it hurt to have this feature?
>