Bob's your uncle

Secondly it needs proper dynamic memory support, without any nasty hacks.

Do you think a BASIC function, doing no more than call some SWIs, fails to do this?

Its should really be an integral part of the language.

Its should really be an integral part of the language.

Of course – see Basalt. ;-)

Secondly it needs proper dynamic memory support, without any nasty hacks.

Do you think a BASIC function, doing no more than call some SWIs, fails to do this?

Yes.
Because that’s not BASIC.

We need, at least, REDIM to change the size of a DIM allocation, and an UNDIM (or REDIM to 0) to release the allocation.
Plus, of course, a shifting heap to keep it all nice and tidy, but I fear that might cause stuff to blow up (look at RMTidy), it might be “interesting” with linked lists. :-/

Because that’s not BASIC.

Yes it is, as much as dealing with the Wimp is. We have libraries for just this purpose.

But if you want it all behind a keyword then:

DIM HIMEM dynamic% 1023:REM claim
DIM HIMEM dynamic% 511:REM redim
DIM HIMEM dynamic% -1:REM undim

I also offer you:

DIM HIMEM dynamic%(1023)
DIM HIMEM dynamic%(511)
DIM HIMEM dynamic%(-1)

But it would need to be able to deal with things like the return from Wimp_GetWindowInfo, that (from memory) returns a window block offset by 4 bytes, because it starts with the window handle, and consists of a window block followed by a number of icon blocks.

Presumably it could just do what other languages have done for years, and allow nested structures? A WindowInfo block contains a window handle and a Window block. The Window block, in turn, contains a number of fields and then zero or more Icon blocks. And so on.

nested structures?

Yup!

Of course we all wait for Daryl releasing the first stable version of DARIC (or maybe even help him with a few pull requests), because it will become the new BBC BASIC. Just a lot better.

Everyone who has not heard of DARIC: watch the video from Daryl’s ROUGOL talk as soon as it is available. In the meantime, read the code: https://github.com/zolbatar/Daric

Or read a short summary here (German, use translation tool of choice): http://riscosblog.huber-net.de/2021/03/interessante-projekte-heute-daric-von-daryl-dudey/