Re: Assigning closure names

[Charles Greathouse <charles.greathouse@case.edu>]

How is Pi handled now (in 2.6.0)?  One still types "Pi" rather than Pi()".

Charles Greathouse
Analyst/Programmer
Case Western Reserve University

On Fri, Jun 22, 2012 at 11:13 AM, Karim Belabas
<Karim.Belabas@math.u-bordeaux1.fr> wrote:
> * Dirk Laurie [2012-06-22 16:54]:
>> Consider the following GP session.
>>
>> ? type(Ser)
>> %1 = "t_CLOSURE"
>> ? type(Vec)
>> %2 = "t_VEC"
>>
>> Deduction: when a built-in function may be called
>> with an empty parameter list, the bare name is
>> interpreted as a function call, not as a reference
>> to the closure.
>
> Originally an old misguided design decision of mine: I had decided to
> allow 'f' as a shortcut for 'f()'.  In the old interpretor -- before
> Bill's rewrite --, this had the small advantage of allowing 'Pi' as a
> shortcut for 'Pi()'.
>
> Note that your specific example only works in pari-stable. In
> pari-2.6.*, Vec() has a mandatory argument.
>
>> Is there a way to access the closure "Vec" as a Pari object?
>
> I do not see any simple way, maybe Bill will have a clever idea.
> Here's a close variant
>
> (17:06) gp > f = x->Vec(x);
> (17:06) gp > type(f)
> %2 = "t_CLOSURE"
> (17:06) gp > f(x + 2)
> %3 = [1, 2]
>
> There's a minor difference, though: f has a mandatory argument, contrary
> to (pari-stable-)Vec.
>
>
> This also works without arguments:
>
> (17:09) gp > f = ()->Pi
> %4 = ()->Pi
> (17:11) gp > f()
> %5 = 3.1415926535897932384626433832795028842
>
> Cheers,
>
>    K.B.
> --
> Karim Belabas, IMB (UMR 5251)  Tel: (+33) (0)5 40 00 26 17
> Universite Bordeaux 1          Fax: (+33) (0)5 40 00 69 50
> 351, cours de la Liberation    http://www.math.u-bordeaux1.fr/~belabas/
> F-33405 Talence (France)       http://pari.math.u-bordeaux1.fr/  [PARI/GP]
> `
>