Hi,
I've just checked, Dyalog APL returns exactly what you are expecting
from it:
2 a[1]
2
b←⍳5
9 8 b
9 8 1 2 3 4 5
9 8 b[2]
8
Elias Mårtenson <loke...@gmail.com> writes:
> On 5 March 2016 at 19:12, Juergen Sauermann <juergen.sauerm...@t-online.de>
> wrote:
>
>
> Hi Alexey,
>
> the IBM APL2 binding rules say that [] binds stronger than vector notation
> (IBM APL2
> language reference page 34). That is,
>
> 100 200[1] is 100 (200[1])
>
> IBM APL2 behaves in the same way as GNU APL.
>
>
> At first I was confused about this (and even started writing this email
> expressing that confusion). Then I
> realised that it is Dyalog that must have a very bizarre evaluator.
>
> What does the following do in Dyalog?
>
> a ← 1
> 2 a[1]
>
> If vector notation binds string that dereference, then this should return 2.
>
> But if that is the case, what does the following return?
>
> b ← ⍳5
> 9 8 b
> 9 8 b[2]
>
> Again, if Dyalog is consistent, it should return 8, and not 9 8 2 which is
> the case in GNU APL.
>
> However, if Dyalog returns the same value as GNU APL, that means that the
> parser changes the binding
> strength depending on the type of arguments. That sounds incredibly weird to
> me.
>
> Regards,
> Elias
>
--
Br,
/Alexey
