Re: Reassignment of a nested array element

[Hans-Peter Sorge]

    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.