Re: /⍨

[hudson]

Hi Jürgen,

There are some APL implementations that accept the form /⍨ .
The GNU APL info manual had a section about the ambiguity of /⌿\⍀ , now 
removed, it seems.

I collected some other issues I have with GNU APL (exceptions caused by user 
errors and more).
See attachments. If you cannot replicate the exceptions, please tell me how to 
try inspect them.

Thanks,
Hudson


----- Em 31 de Maio de 2022, em 17:02, Dr. Jürgen Sauermann 
mail@jürgen-sauermann.de escreveu:

> Hi Hudson,
> 
> I checked with IBM APL2.
> 
> Unfortunately my IBM APL2 has no ⍨ (aka. duplicate) operator.
> But we can emulate it easily:
> 
> DUP ←{ ⍵ ⍶ ⍵ }
> + DUP 1 2 3
> 2 4 6
> × DUP 1 2 3
> 1 4 9
> 
> In GNU APL, DUP gives the same result as ⍨:
> 
> /⍨1 2 3
> SYNTAX ERROR
> /⍨1 2 3
> ^^
> 
> /DUP 1 2 3
> SYNTAX ERROR
> /DUP 1 2 3
> ^^
> 
> However, in IBM APL2 I get the same (see attached screenshot),
> 
> The problem seems to be caused by the ambiguity of / and friends (i.e. ⌿, \, 
> and
> ⍀ ).
> You can work around this with a wrapper around /:
> 
> REPL←{ ⍺ / ⍵ } ⍝ disambiguates / to mean replicate and not reduce
> 3 REPL 1 2 3
> 1 1 1 2 2 2 3 3 3
> 
> REPL ⍨ 1 2 3
> 1 2 2 3 3 3
> 
> 1 2 3 REPL 1 2 3 ⍝ same as REPL ⍨ 1 2 3
> 1 2 2 3 3 3
> 
> Best Regards,
> Jürgen
> 
> On 5/31/22 2:18 AM, [ mailto:hudson@hudsonlacerda.com | 
> hudson@hudsonlacerda.com
> ] wrote:
> 
>> Hi.
> 
>> I get "SYNTAX ERROR" messages for /⍨ or ⌿⍨ :
> 
>> /⍨⍳3
>> ⌿⍨⍳3
> 
>> Regards,
> > Hudson

log
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test.apl
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