This channel is intended for people just starting with the Raku Programming Language ( Logs are available at
Set by lizmat on 8 June 2022.
stevied is there a way to type constrain the elemens in a List that is passed to a method? 00:17
do I do some kind of for loop in the signature?
ok, this worked: `List:D $items where { $items.all ~~ Str}` 00:29
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Khwarizmi hello there, I have a few questions 01:16
readyready15728 Switched over from IRC 01:40
So anyway, my first question is how familiar should I be with Perl 5 if I want to do interop with CPAN packages 01:41
CPAN is still way huger than Raku's equivalent
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SmokeMachine You shouldn’t need to be familiar with Perl… only for translating the module usage to Raku… 02:03
Khwarizmi: 👆 02:10
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stevied how do I loop over a hash sorted by key? I'm trying `for self.items.sort.kv -> $k, $v ` but it's not working 16:33
sienet_ja_LSD[m] I have done at least for %hash.sort( { .keys })>>.kv -> ($k, $v) 16:36
Nemokosch I'm not at a (proper) keyboard but still... there must be a better way 17:45
Util <@563790557831495691> `self.items.sort.kv` does not work, because .sort is returning a list of Pair objects, so `.kv` is operating on a List, and you get (0, FirstPair, 1, SecondPair ...). 19:10
`%hash.sort( { .keys })` , I think is a typo; `.key` is needed, not `.keys`.
Also, the default .sort automatically sorts a List of Pairs by .key first.
The syntax for unpacking a Pair is awkward and hard to remember, but it is optimal for iterating over a sorted hash:
`for %hash.sort -> ( :key($some_variable_for_key), :value($some_variable_for_value) ) { ... }`
Also fine (and easier to remember) is:
`for %hash.sort { my ($k,$v) = .kv; ... }` 19:12
`%hash.sort».kv -> ($k, $v) {...}` is also a fine solution; I have avoided it in code that beginners might use, due to the advanced concepts in hyper-dot method combined with easily-confused use of .kv to mean "unpack a single Pair" instead of "get many keys and values from a single `thing` like a Hash or Array or List". 19:18
`%hash.sort -> (:$key, :$value) {...}` 19:33
Oh! If you don't mind using exactly $key and $value as variable names, you can do this: `%hash.sort -> (:$key, :$value) {...}`
stevied Ah yes. The latter with the hyper operator is what I have used in the path. That is more understandable to me. For whatever reason I couldn’t come up with it. 19:34
Nemokosch (:$key, :$value) isn't bad either for flexibility 19:43
Util <@297037173541175296> Indeed so. Also, when the loop is small, and especially when key and value are accessed no more than once each, I often don't unpack them at all, leaving them in $_ : 19:55
for %hash.sort { do_foo_with(.key); do_bar_with(.value); }
Nemokosch 👍 20:04
stevied ok, got another little problem: I've got a callable in an attribute: `has &.action;` 20:08
i'm trying to execute the callable with $obj.action but that doesn't seem to work
Util <@563790557831495691> Does this work? `$obj.action();` 20:10
stevied doesn't look like it
the action is just a simple one: `action => { say 'action' }`
the raw dump of the object: 20:14
``` => "Option 1", option-number => 1, submenu => => 2, option-format => "\%d - \%s", selection => Str, validated-selection => Str, option-separator => "\n", prompt => Array[Str].new("\nMake selection: "), error-msg => "\nSorry, invalid entry. Try again. ", options => {"1" => => "one", option-number => 1, submenu =
-> ;; $_? is raw = OUTER::<$_> { #`(Block|4385121823648) ... }
the action appears to be there
MasterDuke m: class A { has &.a = -> { say "action" } }; 20:16
camelia action
stevied hmmm 20:18
MasterDuke m: class A { has &.a = -> { say "action" } }; my &b =; b()   # making it a little more obvious what's happening
camelia action
MasterDuke m: class A { has &.a = -> { say "action" } }; my &b =; b()   # first set of parens aren't needed this way 20:19
camelia action
stevied ok, that helped 20:22
yeah, needed the doubled parens 20:25
MasterDuke np
stevied alright, cool. I think I'm ready to drop an honest to god useful module to 20:26
thanks for everyone's help! 20:27
Util So, instead of `$obj.action()`, you can just add a dot: `$obj.action.();`. Cool!
stevied 20:28
Nemokosch Why was the double paren needed though?
stevied there it is! behold!
Util <@297037173541175296> A plain `$obj.action()` was just like `$obj.action`; the parens were part of the method call. 20:29
Nemokosch Well, why isn't it just a method call, really
MasterDuke it was, to get the callable. to call the callable requires another step though 20:30
Nemokosch It's more like a method than a higher order function...
Util Adding another set of parens, or placing a dot between action and parens, means that the final set of parens is an parameterless call to whatever sub is pointed to by the the executed code-so-far.
Nemokosch So ()() is _not_ two consecutive calls? 20:31
Util First one is running `action` to get the contents of the `&.action` attribute. Second `()` is a call to that code. 20:32
Nemokosch The first part is confusing 20:33
stevied I was surpised to see there were no modules in for generating menus. hopefully people find this useful 20:34
Nemokosch Is the first function call for any property?
Util If that is not what is wanted, you can change the way the `action` method works: `has &!.action; method action () { &!.action.() }` 20:35
Then, `$obj.action`, with or without parens, will call whatever sub is stored in &!action, and the outside world cannot get a pointer to the sub itself.
Nemokosch If you want to access a $.var, does it also boil down to a function call?
Util <@297037173541175296> From outside the class, if `var` is a public attribute, then the *method* call (not a sub) of `$obj.var` retrieves the contents of that attribute. So, yes, if I understood your question. 20:37
Nemokosch So the first call is for the property resolution and the second call is the actual function call 20:39
This makes sense eventually
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Util <@297037173541175296> Yes, exactly. 20:41
Nemokosch 🎉 20:44
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stevied 21:10
is that file generated by raku or comma?
it's an *iml file
looks like it's from intellij. Should I keep it out of the repo? 21:12
MasterDuke yeah, i've added *.iml to my .gitignore 21:29
stevied ok, thanks 21:43
ok, now to write the docs. I guess it's time to look to see if there's any automation tools for that that might speed things up. Anything out there? 21:45
i've used mi6 in the past. 21:49
I think that generated a README from the docs.
i probably should have init'ed the module with that instead of comma 21:50
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