Re: [Bug-apl] A question.

[Christian Robert]

With the explanations from Elias I can now see why ⊣⎕←⍵⊣⎕←⍶⊣⎕←⍹⊣⎕←⍵
is completely out of order. "Twilight Zone" says "you are obsolete", that apply 
to me.

loved this small thread. very instructive.

Xtian.

On 2016-05-17 23:12, Xiao-Yong Jin wrote:
> > 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.