> > > @arr3 = @arr1[^i] + @arr2[^i] # also @arr[^i] = @arr1[^i] + @arr2[^i] > > Hyper-operators do this just fine. >
Oh yes they do. The point is that the ^i-loop way is better (more powerful and simpler
at the same time).
Maybe the examples where not good enough.
Take the @b ^/ $a expression. You cannot be sure about what it does until you know the
types of the variables, and this can be not obvious:
$a = (1,2,3);
@b = (2,4,6);
$c = 2;
print @b ^/ $c; #-> 1 2 3
print @b ^/ $a; #-> 2 2 2
In this example the last two lines look exactly the same, but what they do is
quite different. Perl whould do what i mean in both cases, but it's quite probable
that i don't actually know what i mean in the second one. :(
On the other hand:
print @b[^i] / $c;
print @b[^i] / $a[^i];
Is much more clear in the sense that is more explicit. I like explicitness, it makes
me fell safe. That's good. Really.
And you can do operations that are simply not possible with the hyperoperator operator:
print @b[^i] * $a[^j] # -> 2 1 6 4 8 12 6 12 18
# There are much better examples than this one, but it's the first one
# it came to my mind. See the RFC for a bunch of much better ones.
Another example, maybe more important. Imagine you have a good old LOL matrix:
my @matrix = ( ["have", "a"], ["nice", "day" ] );
$b = @matrix^length();# abusing ^ sintax, i guess this will be
# somehow possible. It is imho
# suggested by A3, but it is not said anywhere, so
# maybe it simply cannot be done
$b can be a list of the nested lists' length or a matrix of the scalars' length. It
would probably DWIM for some definition of DWIM-ness, but ¿which one??
I don't know, and if i were a new user (even if i had used hyperoperators before) I
should have to read the docs and probably write a sample program to find out.
But:
$b = @matrix[^i,^j].length() #-> ([4,1],[4,3])
and
$b = @matrix[^i].length() #-> (2, 2)
Are both clear as water. You would never ask what is difference between them.
>
> These can be done in Perl 5 easily enough with map or foreach:
>
> @arr4 = map {$v * $_} @arr1
> $sum += $_ foreach (@arr1)
> @lengths_array = map { length } @arr1
>
> [...]
>
> I don't *dislike* the idea, I'm just pointing out that there's a lot
> of it already in the language. Perhaps making map/foreach/grep more
> flexible with some kind of adverbial modification would be more
> effective (e.g. having a way to specify an incrementor variable or
> the temporary variable for map would allow nested maps to be more
> useful).
>
I understand what you say, but I still believe that the array loop is:
* a more explicit (and thus safer) replacement for hyperoperators
* a _much_ more general and powerful solution
* a smaller adittion to the language # this one could be argable
* more expressive than map/grep/foreach
So what I try to say is that i believe that ^i-loops (or maybe hyperloops ;-)
would be a important addition to Perl, and that in case they were
accepted, the whole hyperoperators family becomes redundant.
By the way, I am not the autor of the idea. I just found the RFC very interesting on
the first time, and it came back to me after reading the A3.
On the other hand, I find your proposal of enhancing of map/foreach/grep using
adverbs very interesting. Could you please provide some examples?
---
Angel Faus
[EMAIL PROTECTED]
""
Description:
""
Description:
""
Description:
""
Description:
""
Description:
""
Description:
