Re: [Bug-apl] IOTA

[Jay Foad]

On 3 March 2016 at 08:12, Elias Mårtenson <address@hidden> wrote:
> What is the purpose of the double-enclose ⊂⊂⍬ ?
>
> My understanding was that (⊂⊂x)≡⊂x for all x?

No! ⊂ is a no-op on simple scalars like 42, but not on enclosures like
⊂⍬. You can enclose most arrays (i.e. anything except simple scalars)
as many times as you like, and they keep getting deeper and deeper.

Hmm, now I see that GNU APL seems to be broken. In APL2 and Dyalog and
NARS2000 I get:

      ≡⊂⊂⊂⊂⊂⊂⊂⊂⊂'elias'
10

But in GNU APL:

      ≡⊂⊂⊂⊂⊂⊂⊂⊂⊂'elias'
2

Jay.