Re: [Bug-apl] A question.

[Xiao-Yong Jin]

> On May 17, 2016, at 9:48 PM, Christian Robert <address@hidden> wrote:
> 
> Sorry, no explanations given.
> 
>      hook←{⍵⍶⍹⍵}
>      +hook÷2
> 2.5
You can look at the definition
      ∇hook[⎕]∇
    ∇
[0]   λ←(⍶ hook ⍹ ) ⍵
[1]   λ←⍵⍶⍹⍵
    ∇
It’s a definition for an operator receiving two function arguments ⍶ and ⍹, for 
which you can not do ⎕←⍹ or ⎕←⍶.  The result is a monadic function with right 
argument ⍵.  Explicitly for the example,
      +hook÷2
is equivalent to
      2+÷2

>      hook←{⍵⍶⍹⍵⊣⎕←⍵⊣⎕←⍶⊣⎕←⍹⊣⎕←⍵}
>      +hook÷2
> 2
> DOMAIN ERROR
> hook[1]  λ←⍵ ⍶ ⍹ ⍵⊣⎕←⍵⊣⎕←⍶⊣⎕←⍹⊣⎕←⍵
>                             ^^
> please explain the principle to a newbie.
> 
> I really want a working examples.
> 
> 
> Xtian.
> 
> 
> On 2016-05-17 22:30, Xiao-Yong Jin wrote:
>> They are for direct function (operator?) definitions.  Try:
>> 
>>      hook←{⍵⍶⍹⍵}
>>      +hook÷2
>> 2.5
>> 
>>> On May 17, 2016, at 8:24 PM, Christian Robert <address@hidden> wrote:
>>> 
>>> hi,
>>> 
>>> in the result of "]help" I can see:
>>> 
>>> 
>>>     λ       { ... } result
>>>     ⍺       { ... } left value argument
>>>     ⍵       { ... } right value argument
>>>     χ       { ... } axis argument
>>>     ⍶       { ... } left function argument
>>>     ⍹       { ... } right function argument
>>> 
>>> 
>>> can someone explain to me the usage of ⍶ and ⍹
>>> with some examples ?
>>> 
>>> I understant the first four, but not the last two.
>>> 
>>> many thanks,
>>> 
>>> Xtian.
>>> 
>> 
>>