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Adám

3:54 AM

@Nissa Welcome, then. Let us know if you need any help, pointers to resources, etc.

4 hours later…

Adám

7:48 AM

@rianoc Hi there. Interested in APL in addition to Q?

@hyper-neutrino Can you edit chat.stackexchange.com/transcript/52405?m=62063400#62063400 so it says "2016-4" instead of "2016-3" and adding the missing "(" for the hyperlink?

2 hours later…

xpqz

9:47 AM

If I bracket index with a semi-colon-separated axis spec, does that have a particular name to distinguish it from bracket index with an array?

Adám

I don't follow. What do you mean by "axis spec"?

xpqz

Arr[1;0;1] vs Arr[⊂1 0 1]

Adám

And how do you index without an array?

@xpqz That's just basic indexing. No axis here.

And note that 1 and 0 and 1 here are arrays, just as much as if you'd written Arr[2 7;1 8;2 8]

xpqz

Ok -- let me reprhase: is the style using semi-colons called something different to those not using semi-colons?

Adám

Yes and no. ⎕A[3 1 4] uses semicolons, right? Specifically 0 of them.

There's no practical difference as long as everything inside the brackets is simple. Once you go nested, there's a difference, and those types have names.

And once you go nested, you can have semicolons.

xpqz

9:53 AM

Right. So what are those names for the nested case?

Adám

Then there's basic, choose, and reach indexing. The latter two implies nested indices.

I plan to cover this in detail at Dyalog '22 — proposing ⊇ of course.

xpqz

I note that this is actually documented nicely (help.dyalog.com/latest/index.htm#Language/Primitive%20Functions/…) -- sorry, should have rtfm

Adám

@xpqz Also see the wiki.

xpqz

10:33 AM

fwiw, I'm doing this in the open from now on: github.com/xpqz/skalpel (my "apl-alike") -- but it's not feature complete enough to do much of anything really.

Richard

11:03 AM

@xpqz
" The general advice to someone wanting to make their own programming language is typically don't. If you want to make your own array language, you need special permission from the Ministry of Vector Processing. "
:)

Quite some effort you are doing!

3 hours later…