Re: [Bug-apl] Extension proposal: ⍵⍵ to access outer lambda

[Elias Mårtenson]

Point taken, and I have no intention to fight for this one right now. :-)

Just to answer your question: ⍵⍵⍵ would refer to the outer-outer lambda, which ⍵⍵ would raise an error. The same goes for ⍶, ⍹ and χ. I'd say it's hard to argue for any other variant.

That said, the workaround by assigning to a different variable would be usable, if we had lexically bound variables.

Regards,

Elias

On 20 July 2014 23:05, Juergen Sauermann <address@hidden> wrote:

Hi,

maybe not that bad but there are complications.

First of all: non-standard.

Secondly some users have already indicated that we would also need ⍺⍺⍺/⍵⍵⍵, ⍺⍺⍺⍺/⍵⍵⍵⍵,
and so forth. But what if some outer lambdas dont have an ⍺? would eg. ⍺⍺⍺ be undefined then
or would ⍺⍺⍺⍺ become ⍺⍺⍺ instead? And how about not-present χ-es?

This all together looks rather odd to me. I see more problems than benefits in these cases and
would recommend good old standard APL functions instead where all the desired features that are
missing in GNU-APL lambdas are present.

/// Jürgen

On 07/10/2014 02:03 AM, Kacper Gutowski wrote:

On 2014-07-09 16:14:32, Juergen Sauermann wrote:

Hi,

actually - no. I called it OUTER_OMEGA to make clear what it does.
Maybe you like

       { ⍵ + {⍵×WW} 10 ⊣ WW←⍵ } 100
1100

imore?

I think the main problem isn't the length of variable's name but the
fact that regular variable is neither lexically scoped nor localized.

Using ⍵⍵ might be confusing for Dyalog users where ⍺⍺ and ⍵⍵ are used
as functional arguments of dfn operators.  But since GNU APL uses ⍶
and ⍹ for those and it doesn't localize variables in dfns, using
repeated ⍺/⍵ for nested arguments doesn't sound that bad.


-k