On Tue, 06 Oct 2020, William Michels via perl6-users wrote:
> [...]
>
> So my question regards "special-casing" of split/join in Raku. Is the first
> result on comma-delimited data the default, i.e. joining disparate elements
> of an array together head-to-tail? Or is the second result on
> whitespace-delimited data the default (i.e. no joining of disparate
> elements together head-to-tail)? Which one is special-cased? If the second
> one is special-cased, is that why Raku returns 5 elements and not 4
> elements as in lines C/D (implied join)?
>
My answer is going to be that there is *no* special-casing. You have an
array of strings @a and you call the `split` and `join` methods on it.
These two methods are not alike. `join` is a proper method of List and
it joins stringifications of the elements of that list.
Crucially, the `split` method comes from somewhere else: Array inherits
it from the Cool class. When you call Array.split, what happens is that
your entire array gets stringified first (joining stringifications of
its elements with spaces) and then Cool.split is called on that string
representation of your array. This is even mentioned in the introductory
paragraph about Cool [1].
This is the strangely consistent explanation of the effects you observed.
You see, the only "special" thing is that Array.split being a Cool method
causes the array to be joined with *spaces* before the splitting starts,
but this always happens, independently of the join/split arguments.
Array.split does in particular *not* "pass on" the split call to the
elements of the array. For that you would use @a».split, although this
would cause (itemized) Seqs for each element of @a to end up in the
returned list, so what you actually thought you were doing may be
written as
@a».&{ .split(",").Slip }
I am sure there are ways to write it more alphabetically.
Best,
Tobias
[1] https://docs.raku.org/type/Cool
--
"There's an old saying: Don't change anything... ever!" -- Mr. Monk
