I’m unable to make sense of this explanation. My u...

# compose

[min]

I’m unable to make sense of this explanation. My understanding of a gap buffer is that
1. It owns a buffer to store T elements in,
2. And has a notion of a ‘gap’ slice that’s uninitialised to be written to
A naive minimal implementation can be given by a struct { buffer, gap_range }. I don’t understand how an array of (what I presume are) inlined serialisations of groups, and a ‘`slots` array’ implement a gap buffer. Moreover, what’s a slot?

[min]

They’re both gap buffers, and groups just correspond to ranges of slots?

[min]

Just the slots array is a gap buffer?

[shikasd]

Slot corresponds to a single `remember`'ed value. Gap buffer is really irrelevant here, composition is just a tree that was represented as a flat array (think how PriorityHeap works). Gap buffer was there for faster updates, and is no longer there in the new LinkTable impl.

[min]

@shikasd This explanation seems, to me, to contradict what’s suggested by diagrams such as this.
> Slot corresponds to a single `remember`'ed value
I’ve been led to believe that a ‘group’ is a handle on, and corresponds to, a slice of ‘slots’ which are populated by serialised tree data. Are you saying that it’s just stuff cached by remember?

[shikasd]

Here's a slide I used when talking about these things before, it is more correct if you detach from implementation details

[shikasd]

Are you saying that it’s just stuff cached by remember?

Yeap, that and composer.changed, which is effectively internal remember

[shikasd]

Group is technically a slice of slots, but each slot is effectively a remembered value

[shikasd]

The whole concept of group is to make sure that slots are added and removed correctly for positional memoization

[min]

@shikasd So to summarise,
Q: …I’ve been led to believe that a ‘group’ is a handle on, and corresponds to, a slice of ‘slots’…
A: Group is technically a slice of slots…
Q: …[each slot is] just stuff cached by remember?
A: effectively a remembered value
Got it, thanks!