Dear Fred,
While your code does help in one area, it has a problem in another, i.e.:
gg←,'' 'a' 'b'
⍴gg
3
Your code says there are three but to the programmer there are only two.
The '' is just there to make the rest work. I suppose you can just
remember that and change your indexes everywhere and hope someone else
reading the code gets it.
Also, in:
( unbox unbox unbox box box box 6 ) ≡ ⊃ ⊃ ⊃ ⊂ ⊂ ⊂ 6
They are not equivalent at all. Each box adds additional levels of nesting
as the programmer is specifying. Each ⊂ above is a null function. This is
actually the main point. box always gives you an additional level of
nesting regardless of data. ⊂ always gives you an additional level of
nesting unless your data happens to be a scalar. What you end up with is
dependent on the data. It is almost like saying that:
x times y gives the result of multiplying x by y, unless x is 88 then we
add.
The operation shouldn't be dependent on the data.
Additionally, you would have to either encapsulate your idiom into a
function or remember the extra steps everywhere - and remember when to use
it and when not to use it.
I am sure there are many ways to skin a cat, or solve this problem. I
think mine is cleaner.
Thanks for your input!
Blake
On Mon, May 19, 2014 at 10:34 PM, Frederick H. Pitts <[email protected]
> wrote:
> Blake,
>
> Since box and unbox are implemented directly in terms of enclose
> and
> disclose, I have to believe that the latter can handle the parameters
> you require and in a less verbose fashion.
>
> Consider the following code:
>
> gg ← ,'' 'a' 'b'
> gg
> ┌→─────┐
> │┌⊖┐ ab│
> ││ │ │
> │└─┘ │
> └∊─────┘
> hh ← ,'' 'ab'
> hh
> ┌→───────┐
> │┌⊖┐ ┌→─┐│
> ││ │ │ab││
> │└─┘ └──┘│
> └∊───────┘
>
> If the first element of a nested array is a vector, any vector,
> subsequent scalar character elements remain scalar and are not coalesced
> into a vector. hh is presented to highlight the difference between a
> sequence of scalar character elements and a character vector. There are
> 3 elements in gg and only 2 in hh. I'm of the opinion that box/unbox
> work because the box function stuffs a vector in the first element of
> the nested array. If not, sequential homogeneous scalars are going to
> be coalesced to form a vector element. A requirement for a nested array
> to exist is that it contain at least one vector element. The remaining
> elements can be scalar. enclose is not going to produce a nested array
> unless a vector element is supplied and if one is not supplied, enclose
> will attempt to create one.
>
> Please consider the attached code. It demonstrates that enclose
> (actually implicit enclose), dyadic pick and parallel assignment can
> more succinctly do what the box/unbox pair do, but admittedly at the
> slight complication of having to supply and account for the vector first
> element in the nested array and its nested array elements. That
> complication seems a small price to pay for not having to box and unbox
> every element of a nested array.
>
> Regards,
>
> Fred
> Retired Chemical Engineer
>
>
