Re: [Bug-apl] Power Operator (⍣) broken at svn 740 ?

[Xiao-Yong Jin]

Hi Jüergen and Christian,

> On Jun 12, 2016, at 4:28 AM, Juergen Sauermann <address@hidden> wrote:
> 
> the reason is that the arguments of the right function argument of ⍣
> have different lengths and are therefore always unequal:
> 
>       FIB←{ 3↓ {⍵,+/¯2↑⍵}⍣{(↑⍵)≤¯3+⍴⍺ ⊣ ⎕←'debug:' (⍴⍵) 'vs' (⍴¯3+⍴⍺)} ⊢ ⍵, 0 
> 1 }
>       FIB 12
>  debug:  3  vs  1 
>  debug:  4  vs  1 
>  debug:  5  vs  1 
>  debug:  6  vs  1 
>  debug:  7  vs  1 
>  debug:  8  vs  1 
>  debug:  9  vs  1 
>  debug:  10  vs  1 
>  debug:  11  vs  1 
>  debug:  12  vs  1 
>  debug:  13  vs  1 
>  debug:  14  vs  1 
>  debug:  15  vs  1 
>  debug:  16  vs  1 
>  debug:  17  vs  1 
>       ...
> 
> The power operator is now a macro which uses ≡ instead of ↑=
> (which was sort of working, but wrong). The Dyalog manual says:
> 
> "The right argument  must be a dyadic function that returns a Boolean scalar",

Despite what is in their manual, dyalog seems to treat 1 scalar element vector 
as a scalar here,
      ⎕ML←2       
      FIB←{ 3↓ {⍵,+/¯2↑⍵}⍣{(↑⍵)≤¯3+⍴⍺ ⊣ ⎕←'debug:' (⍴⍵) 'vs' (⍴¯3+⍴⍺)} ⊢ ⍵, 0 1 
}
      FIB 12
 debug:  3  vs  1
 debug:  4  vs  1
 debug:  5  vs  1
 debug:  6  vs  1
 debug:  7  vs  1
 debug:  8  vs  1
 debug:  9  vs  1
 debug:  10  vs  1
 debug:  11  vs  1
 debug:  12  vs  1
 debug:  13  vs  1
 debug:  14  vs  1
1 2 3 5 8 13 21 34 55 89 144 233