understanding mir, generic nd array iterator

[monkyyy]

I asked
> does a preexisting nd array iterator exist?

got links to mir, docs I can barely read (srsly math language is 
anticomprehension)

ndslice allocates, so, hottake misnamed. A slice is a reference 
to an array, a dynmaic array is a gc allocated array 
https://opendlang.org/library/mir.ndslice.allocation.slice.4.html#Slice

Found `field`, says its a something defined by an opIndex, 
better, but no nd

`fieldnd.d`or something exists but it defines 2 types of nd 
fields and not a generic mapping, idk

`FieldIterator` exists but its opSlice only takes 2 arguments so 
I think I can rule it out as nd

etc.

So I dont think it exists in this tangled mess? Maybe, idk? I 
think in its naming scheme it would be called an ndfield