Hi Jürgen,
back from wintry Hahnenklee/Harz here are my thoughts.
In ref.: "like a variable or like part of variable"
I always look at the intermediate data content which I consider to be
identical from "variable point of view" and "part of variable point of
view".
In following example that symmetry gets broken.
V
A 1 2 3 4 5 1 1 1
1 1 1
1 1 1
(1/3⊃V) ≡ 3⊃V
1
(3⊃V)←1
(1/3⊃V) ≡ 3⊃V
0
The test case you attached
(1/3⊃V)←3 2⍴'ABCdef'
does what I would expect and it looks like it is in "variable context'.
Would the result differ if the case would be handled in "part of
variable context"?
Best Regards
Hans-Peter
Am 10.03.23 um 16:54 schrieb Dr. Jürgen Sauermann:
Gentlemen,
thanks for your patience. I believe that I have now found a
solution that may please both of you. Attached is my testcase
file, please have a look.
I still believe that left values using *A⊃V* or *A/B* are ambiguous
as to whether their result shall be treated like a variable or like
part of variable (see my previous comment on *V←* vs. *V[]←*).
The fact that other APL interpreters decide that in one way or
the other seems not really satisfactory but somewhat arbitrary.
I would therefore propose to avoid such constructs for the sake
of portability.
Best Regards,
Jürgen
On 3/9/23 6:56 PM, Hans-Peter Sorge wrote:
Hi Jürgen,
thank you for considering it.
Your work is admirable.
Best Regards
Hans-Peter
Am 09.03.23 um 17:49 schrieb Dr. Jürgen Sauermann:
Hi Hans-Peter,
you are probably right. This one looks rather tricky, therefore
I may need some time. But I am working on it.
Best Regards,
Jürgen
On 3/8/23 9:05 PM, Hans-Peter Sorge wrote:
Hello Jürgen,
sorry that I'm so insistent
in
APL2 Programming:Language Reference
it is stated:
Selective Specification:Compress can be used for selective
specification:
M←32ρι6
M
12
34
56
(10/M)←'ABC'
M
A2
B4
C6
Using our example V
V←1 'bc' M
V
1 bc 1 2
3 4
5 6
The selective specification
(1 0/3⊃V)←'ABC'
V
1 bc ABC
does not yield the same content for 3⊃V as for modified M.
Best Regards
Hans-Peter
Am 08.03.23 um 17:44 schrieb Dr. Jürgen Sauermann:
Hi,
I fixed a discrepancy between (3⊃V)← and (1/3⊃V)←. *SVN 1657*.
We know have:
* V←1 'bc' (3 3⍴⍳9) ◊ 8 ⎕CR V**
**┌→─────────────┐**
**│1 ┌→─┐ ┌→────┐│**
**│ │bc│ ↓1 2 3││**
**│ └──┘ │4 5 6││**
**│ │7 8 9││**
**│ └─────┘│**
**└ϵ─────────────┘**
** (3⊃V)←1 ◊ 8 ⎕CR V**
**┌→───────┐**
**│1 ┌→─┐ 1│**
**│ │bc│ │**
**│ └──┘ │**
**└ϵ───────┘**
** (1/3⊃V)←1 ◊ 8 ⎕CR V**
**┌→───────┐**
**│1 ┌→─┐ 1│**
**│ │bc│ │**
**│ └──┘ │**
**└ϵ───────┘*
However, I don't quite get why, as suggested below, the results of
*(3⊃V)←* and of *(1/3⊃V)**←* should differ?
For me *1/X* is the same as *X* (except for a length 1 axis added
by 1/ when*X* is
scalar) and therefore *(3⊃V)←1 *and *(1/3⊃V)←1 *should IMHO yield
the same.
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 SVN 1657
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.
