Re: Reassignment of a nested array element

[Elias Mårtenson]

I think this is because monadic ⊃ is first in Dyalog, as opposed to
disclose in GNU, APL2 (and, incidentally, KAP 😀).

Use monadic ↑ instead to get the effect you want.

Den ons 8 mars 2023 00:34Dr. Jürgen Sauermann <mail@jürgen-sauermann.de>
skrev:

> Hi Hans-Peter,
>
> I believe that GNU APL, Dyalog, and IBM APL2 only now behave
> the same while GNU APL did not before the fix:
>
> T*ryAPL Version 3.6.1 (enter ]State for details)*
> *Tue Mar 07 2023 16:59:04*
> *Copyright (c) Dyalog Limited 1982-2023*
> *      Q←0 0 0*
> *      (3⊃Q)←2 2⍴2*
> *      Q*
> *┌─┬─┬───┐*
> *│0│0│2 2│*
> *│ │ │2 2│*
>
>
> *└─┴─┴───┘ **      (3⊃Q)←33*
> *      Q*
> *0 0 33*
>
> *GNU APL SVN 1656:*
>
> *     Q←0 0 0*
> *      (3⊃Q)←2 2⍴2*
> *      Q     *
> * 0 0   2 2 *
>
>
> *       2 2 **      (3⊃Q)←33*
> *      Q     *
> *0 0 33*
>
> The cleanest way to achieve the previous (incompatible)
> behaviour in GNU APL is to disclose the left of →
>
> *      Q←0 0 0*
> *      (3⊃Q)←2 2⍴2*
> *      Q     *
> * 0 0   2 2 *
>
>
> *       2 2 **      (⊃3⊃Q)←33*
> *      Q*
> * 0 0   33 33 *
> *       33 33 *
>
> For dubious reasons this does not work on Dyalog
> because they only assign the first item:
>
> *      (⊃3⊃Q)←33*
> *      Q*
> *┌─┬─┬────┐*
> *│0│0│33 2│*
> *│ │ │ 2 2│*
> *└─┴─┴────┘*
>
> which is not consistent with (Dyalog):
>
> *      W←⊂2 2⍴2*
> *      W*
> *┌───┐*
> *│2 2│*
> *│2 2│*
>
>
> *└───┘ **      (⊃W)←33*
> *      W*
> *33*
>
> Although this is a discrepancy between GNU APL and Dyalog,
> I believe that Dyalog is wrong here. IBM APL2 says
> DOMAIN ERROR in this case.
>
>
> Best Regards,
> Jürgen
>
>
> On 3/6/23 9:16 PM, Hans-Peter Sorge wrote:
>
> Hello Jürgen,
>
> I agree with your case 1/2  Statement.
>
> The examples I was showing is actually "off by 1".
>
>  I was referring to
> (1/3⊃V)←1
>
> having
>      a←1
>      b←'ABC'
>      c←3 3⍴⍳9
>      V←a b c
>      (3⊃V)
> 1 2 3
> 4 5 6
> 7 8 9
> As expected with case 1:
>      (3⊃V)←1
>      V
> 1 ABC 1
>
>      V←a b c
> Not expected:
>      (*1/*3⊃V)←1
>      V
> 1 ABC 1
>
> Expected:
>      (1/3⊃V)←1
>      V
> 1 ABC   1 1 1
>         1 1 1
>         1 1 1
>
> as with
>      (1/c)←1
>      c
> 1 1 1
> 1 1 1
> 1 1 1
>
> And that's Dyalog too.
> Please restore compatibility:-)
>
> Best Regards
> Hans-Peter
>
>
> Am 06.03.23 um 16:10 schrieb Dr. Jürgen Sauermann:
>
> Gentlemen,
>
> thanks for the discussion, fixed in *SVN 1655*.
>
> Hans-Peter, I am sorry that this change creates an incompatibility in your
> code.
>
> My thinking for the old solution was this:
>
> *   V←0 0 0**  ◊   V←1 ◊ V   ∩ case 1.*
> *1*
>
> *   V←0 0 0**  ◊   V[]←1 ◊ V   ⍝ case 2.*
> *1 1 1*
>
> This applies to GNU APL, APL2, and Dyalog. The question is then if (A⊃V) in
> (A⊃B)←X should behave like case 1 or like case 2 above. The case (A⊃B)←X
> with nested (A⊃B)is described neither in the "IBM APL2 Language Reference"
> nor in the "ISO 13751" standard, leaving some room for interpretation.
>
> However, both APL2 and Dyalog agree on case 1 and therefore I changed
> GNU APL to behave the same.
>
> Best Regards,
> Jürgen
>
>
>
> On 3/4/23 8:25 PM, Hans-Peter Sorge wrote:
>
> Hi,
>
> Works as expected
>
> ⊃'Sue' 'Maria' 'Annalisa'
> is an array 3 by 8.
>
> ⊂⊃'Susan' 'Mary' 'Annalisa'
> is an element (⊂) of a 3 by 8  array (⊃'Susan' 'Mary' 'Annalisa' ).
>
> Finally each element in  ⊃'Sue' 'Maria' 'Annalisa' gets assigned an array
> of  ⊃'Susan' 'Mary' 'Annalisa'
>
> Greetings
> Hans-Peter
>
> Am 04.03.23 um 16:53 schrieb Mr. Sunday:
>
> Hi,
>
> I have an issue with reassigning an element of a nested array.  Here is an
> example.
>
> 14535:15a:~% apl --version
> BUILDTAG:
> ---------
>      Project:        GNU APL
>      Version / SVN:  1.8 / SVN: 1651M
>      Build Date:     2023-03-02 00:25:07 UTC
>      Build OS:       Darwin 21.6.0 x86_64
>      config.status:  default ./configure options
>      Archive SVN:    1621
>
>
>      var←0 0 0 ⋄ (1⊃var)←5 4 ⋄ (2⊃var)←3 4⍴⍳12 ⋄ (3⊃var)←⊃'Sue' 'Maria'
> 'Annalisa' ⋄ var ⋄ (3⊃var)←⊂⊃'Susan' 'Mary' 'Annalisa' ⋄ var
> ┌→────────────────────────────┐
> │┌→──┐ ┌→─────────┐ ┌→───────┐│
> ││5 4│ ↓1  2  3  4│ ↓Sue     ││
> │└───┘ │5  6  7  8│ │Maria   ││
> │      │9 10 11 12│ │Annalisa││
> │      └──────────┘ └────────┘│
> └ϵ────────────────────────────┘
> ┌→───────────────────────────────────────────────────────────────────────────────────────────────────────────┐
>
> │┌→──┐ ┌→─────────┐
> ┌→──────────────────────────────────────────────────────────────────────────────────────┐│
> ││5 4│ ↓1  2  3  4│ ↓┌→───────┐ ┌→───────┐ ┌→───────┐ ┌→───────┐
> ┌→───────┐ ┌→───────┐ ┌→───────┐ ┌→───────┐││
> │└───┘ │5  6  7  8│ │↓Susan   │ ↓Susan   │ ↓Susan   │ ↓Susan   │ ↓Susan
> │ ↓Susan   │ ↓Susan   │ ↓Susan   │││
> │      │9 10 11 12│ ││Mary    │ │Mary    │ │Mary    │ │Mary    │ │Mary
> │ │Mary    │ │Mary    │ │Mary    │││
> │      └──────────┘ ││Annalisa│ │Annalisa│ │Annalisa│ │Annalisa│
> │Annalisa│ │Annalisa│ │Annalisa│ │Annalisa│││
> │                   │└────────┘ └────────┘ └────────┘ └────────┘
> └────────┘ └────────┘ └────────┘ └────────┘││
> │
> │
> ││
> │                   │┌→───────┐ ┌→───────┐ ┌→───────┐ ┌→───────┐
> ┌→───────┐ ┌→───────┐ ┌→───────┐ ┌→───────┐││
> │                   │↓Susan   │ ↓Susan   │ ↓Susan   │ ↓Susan   │ ↓Susan
> │ ↓Susan   │ ↓Susan   │ ↓Susan   │││
> │                   ││Mary    │ │Mary    │ │Mary    │ │Mary    │ │Mary
> │ │Mary    │ │Mary    │ │Mary    │││
> │                   ││Annalisa│ │Annalisa│ │Annalisa│ │Annalisa│
> │Annalisa│ │Annalisa│ │Annalisa│ │Annalisa│││
> │                   │└────────┘ └────────┘ └────────┘ └────────┘
> └────────┘ └────────┘ └────────┘ └────────┘││
> │
> │
> ││
> │                   │┌→───────┐ ┌→───────┐ ┌→───────┐ ┌→───────┐
> ┌→───────┐ ┌→───────┐ ┌→───────┐ ┌→───────┐││
> │                   │↓Susan   │ ↓Susan   │ ↓Susan   │ ↓Susan   │ ↓Susan
> │ ↓Susan   │ ↓Susan   │ ↓Susan   │││
> │                   ││Mary    │ │Mary    │ │Mary    │ │Mary    │ │Mary
> │ │Mary    │ │Mary    │ │Mary    │││
> │                   ││Annalisa│ │Annalisa│ │Annalisa│ │Annalisa│
> │Annalisa│ │Annalisa│ │Annalisa│ │Annalisa│││
> │                   │└────────┘ └────────┘ └────────┘ └────────┘
> └────────┘ └────────┘ └────────┘ └────────┘││
> │
> └ϵ──────────────────────────────────────────────────────────────────────────────────────┘│
> └ϵϵ──────────────────────────────────────────────────────────────────────────────────────────────────────────┘
>
>
> -- Everyday is Sunday.
>
>
>
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