COMBINE doesn't know APPEND's base case (and others)

[brianharvey]

When we turned a bunch of former library blocks into primitives, some variadic ones should have been added to COMBINE's list of base cases:


Don't forget that in COMBINATIONS the base case result isn't empty:

COMBINE also lost the base cases of some formerly dyadic blocks that have become variadic:




These latter ones are sort of important even though I gave this a "low priority" label, because I think we use them in BJC.

These are all the ones I found but I didn't carefully check every block.

[jmoenig]

thanks!
(although I'm 100% sure that we've never in the past special-cased those base-cases in any version of combine, so I'm having a hard time believing that BJC teaches about them).
Will try to fix it!

[ego-lay-atman-bay]

That's how they behave in snap 9.2.10

[brianharvey]

Umm okay I guess what I meant is that BJC uses COMBINE USING AND/OR, not that it does so with empty lists; of course if you know the list is empty you don't need COMBINE at all. It's just that you run the risk that a list might turn out to be empty in an unusual situation that still isn't a (user) bug, e.g., COMBINE (KEEP ...) USING AND.

Anyway, I'm not claiming it's a new bug in dev!

[ego-lay-atman-bay]

Oh, I must've read this

When we turned a bunch of former library blocks into primitives

And thought it said

When we turned primitives to blocks

So I thought you were suggesting it was a bug introduced in the dev version.