On Fri, 14 Sep 2018, 11:22 Todd Chester, <toddandma...@zoho.com
<mailto:toddandma...@zoho.com>> wrote:
Hi All,
I adore the "kv" method:
$ p6 'for "abc\n23\n4.56".lines.kv -> $i, $j { say "$i $j" };'
0 abc
1 23
2 4.56
So, I decided to go and look at:
https://docs.perl6.org/routine/kv
multi method kv(Any:U: -->List)
multi method kv(Any:D: -->List)
Okay, here is what I see:
"method" is .foo style of a routine
"Any:U:" and "Any:D:" are what goes in front of .foo
and it can be of type "Any".
https://docs.perl6.org/type/Any
":D" mean constrained, meaning it much have something
What is ":U"?
Whatever ":U", how can it be both?
The second ":" is the delimiter for what goes in front of the .foo,
meaning it has finished its declaration of what that in front is.
Kind of like a comma.
"-->List" mean something is returned of type "List"
https://docs.perl6.org/type/List
0 abc
1 23
2 4.56
How have I done so far?
And is there a list somewhere of the meanings of ":U" and ":D"
and such so the next time I see one that I do not recognize,
I can look it up?
Many thanks,
-T
On 09/14/2018 03:28 AM, Simon Proctor wrote:
:D means a defined value. So it's when you have an instance. :U is
undefined so it's when you call kv as a classethod.
Pair.kv would be :U.
(A => "b").kv would be :D
Hi Simion,
I am not following. What do you mean by "undefined"?
I can't make head or tails out of "Pair"
https://docs.perl6.org/type/Pair
I thought ":D" meant "constrained"?
Yours in confusion ,
-T
