[Jprogramming] cap

[Raul Miller]

On Mon, Jul 23, 2012 at 4:57 PM, Dan Bron <j at bron.us> wrote:
> Raul wrote:
>>  It's defined as having an empty domain --
>>  why not rely on the  definition being
>>  accurate?
>
> Cap's raison d'etre is grammatical, not semantic.  That it is a verb, and
> that its domain is defined to be empty, is incidental.  I prefer for my code
> to recognize this, and not hinge on incidentals, or encourage others to do
> so.

This kind of reasoning -- that a language primitive should not be
treated as having utility explicitly stated in the documentation of
that primitive, and obviously present in the implementations -- does
not make sense to me.

>>  I think of a raised error as a "violation of type" issue.
>
> I think we can agree that one of the guiding principles in the design of J
> is "graceful degradation"; witness, e.g., %. which has rank 2 but works "as
> expected" on vector and scalar arguments.  There are innumerable other
> examples.  I prefer to maintain this principle as far as I can, in my own J
> code.  Of course, there always comes a tipping point, but one hopes to defer
> that as long as possible (or reasonable).

But those are not cases where either the implementation or the
dictionary state that there should be an error.  So I am not sure how
this observation is relevant in this context.

(Unless, for example, you are considering errors like length error.
But I think we can agree that length error from %. constitutes an
error in the code which provides the data?)

Am I missing something here?

Thanks,

-- 
Raul