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, [email protected] 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
