Re: [Bug-apl] dynamic function not referencing global?

[Christian Robert]

Niladic Lambda can be usefull.

I wonder if it could be possible to use some trick to generate niladic Lambda.


Like in:


      )erase time

      time←{⎕TS ;x}

Since this lambda has a local variable defined, then it should be a definition 
and since

there is no ⍵ nor ⍺ then it should be niladic one.

Only Juergen can say if it is possible, or find an other trick and how hard to 
implement ...

Just some personnal tought.

Xtian.


On 2016-10-26 06:54, Juergen Sauermann wrote:
> Hi,
>
> correct. To explain why this is so, consider this:
>
> *     {1+2}**
> **3
>
> **      {1+⍵}**
> **SYNTAX ERROR*
>
> *      {1+⍵} 5**
> **6**
> *
> Therefore in
>
> *      F0←{1+2}*
>
> GNU APL first reduces *{1+2} *to *3* and then assigns *3* to *F0*, making *F0* 
> a variable
> because a values is being assigned to a name. This is normal APL and holds for
> all niladic functions and not only for niladic lambdas.
>
> In contrast, in
>
> *      F1←**{1+⍵}
> *
> **{1+⍵}**cannot be reduced (as opposed to *{1+⍵} 5*which can), so it is shifted 
> onto
> the evaluation stack, then *←* is shifted (still not being able to be reduced), 
> and finally
> *F1* is shifted. At this point the stack contains the valid phrase 
> *F1←**{1+⍵}*, which can
> be reduced and causes *F1 *to become a monadic function bound to the name *F1*.
>
> /// Jürgen
>
>
> On 10/25/2016 07:01 PM, Christian Robert wrote:
> > DISPLAYhand←{,(⍪hand),' '}
> >
> > this create a variable DISPLAYhand
> >
> > this is because de {} does not contain neither alpha nor omega.
> >
> > Xtian.
> >
> >
> > On 2016-10-25 12:54, address@hidden wrote:
> > > Hi bug-apl,
> > >
> > > Why does DISPLAYhand not use the new value of hand on the second call?
> > >
> > >
> > >       deck←''
> > >       deck←deck,"🂢" "🂲" "🃂" "🃒"
> > >       deck←deck,"🂣" "🂳" "🃃" "🃓"
> > >       deck←deck,"🂤" "🂴" "🃄" "🃔"
> > >       deck←deck,"🂥" "🂵" "🃅" "🃕"
> > >       deck←deck,"🂦" "🂶" "🃆" "🃖"
> > >       deck←deck,"🂧" "🂷" "🃇" "🃗"
> > >       deck←deck,"🂨" "🂸" "🃈" "🃘"
> > >       deck←deck,"🂩" "🂹" "🃉" "🃙"
> > >       deck←deck,"🂪" "🂺" "🃊" "🃚"
> > >       deck←deck,"🂫" "🂻" "🃋" "🃛"
> > >       ⍝deck←deck,"🂬" "🂼" "🃌" "🃜"   ⍝knights
> > >       deck←deck,"🂭" "🂽" "🃍" "🃝"
> > >       deck←deck,"🂮" "🂾" "🃎" "🃞"
> > >       deck←deck,"🂡" "🂱" "🃁" "🃑"
> > >       deck ← ⊖13 4 ⍴ deck
> > >
> > >       hand←(∈deck)[13?52]
> > >       DISPLAYhand←{,(⍪hand),' '}
> > >
> > >       DISPLAYhand
> > > 🂢 🃈 🃃 🂷 🃞 🃙 🃝 🂫 🃋 🃕 🃒 🃂 🂧
> > >       hand←(∈deck)[13?52]
> > >       DISPLAYhand
> > > 🂢 🃈 🃃 🂷 🃞 🃙 🃝 🂫 🃋 🃕 🃒 🃂 🂧
> > >       hand
> > > 🂤🂺🂾🂷🂪🂱🂳🂸🃚🃅🂻🂲🂭
> > >
> > >
> > > Thanks,
> > > Alex