raku

问题 I'm attempting to implement a class that 'does' Positional that also allows me to update its values by assigning to the result returned by the AT-POS method. Eventually, I was able to concoct the following class that works as intended: class Test does Positional { has $.slot_1 is rw = 12; has $.slot_2 is rw = 24; method AT-POS(\position) { my $t = self; return-rw Proxy.new: FETCH => method () { position % 2 ?? $t.slot_1 !! $t.slot_2 }, STORE => method ($v) { if position % 2 { $t.slot_1 = $v }

问题 I may be suffering from brain fade, but according to the docs regarding Items and List assignment (https://docs.raku.org/language/variables#Item_and_list_assignment ), Assignment to a List container (list-context) always triggers list assignment. However that seems to conflict with what I get from the code (here reproduced in the raku repl).. > my %syns-by-name = %(Bq => ["Bq", "becquerel", "becquerels"], C => ["C", "coulomb", "coulombs"],) {Bq => [Bq becquerel becquerels], C => [C coulomb

问题 In contrast with Perl 5, Raku introduced gradual typing. The landscape of gradually typed object-oriented languages is rich and includes: Typed Racket, C#, StrongScript, Reticulated Python. It's said that "optional gradual type-checking at no additional runtime cost" on the Raku official website. As far as I know, some gradual typing language (like Typed Racket and Reticulated Python) suffered from the serious performance issue due to strategy of enforcing type system soundness. On the other

问题 Raku's regexes are expected to match longest token. And in fact, this behaviour is seen in this code: raku -e "'AA' ~~ m/A {say 1}|AA {say 2}/" # 2 However, when the text is in a variable, it does not seem to work in the same way: raku -e "my $a = 'A'; my $b = 'AA'; 'AA' ~~ m/$a {say 1}|$b {say 2}/" # 1 Why they work in a different way? Is there a way to use variables and still match the longest token? 回答1: There are two things at work here. The first is the meaning of "longest token". When

问题 I'm trying to use NativeCall to interact with some C functions. I have a simple C struct, and a function that wants an array of them. struct foo { int x; char *s; }; struct foo foo_array[3]; foo_array[0].x = 12; foo_array[0].s = "foo"; foo_array[1].x = 27; foo_array[1].s = "bar"; foo_array[2].x = -1; void somefunc(foo_array); I've tried a bunch of ways, but can't seem to get it quite right. class foo is repr('CStruct') { has int32 $.x; has Str $.s }; sub somefunc(CArray[foo]) is native { * }

问题 I'm trying to use NativeCall to interact with some C functions. I have a simple C struct, and a function that wants an array of them. struct foo { int x; char *s; }; struct foo foo_array[3]; foo_array[0].x = 12; foo_array[0].s = "foo"; foo_array[1].x = 27; foo_array[1].s = "bar"; foo_array[2].x = -1; void somefunc(foo_array); I've tried a bunch of ways, but can't seem to get it quite right. class foo is repr('CStruct') { has int32 $.x; has Str $.s }; sub somefunc(CArray[foo]) is native { * }

来源： https://stackoverflow.com/questions/48899148/how-can-i-tell-programmatically-if-a-perl-6-module-is-installed

来源： https://stackoverflow.com/questions/48899148/how-can-i-tell-programmatically-if-a-perl-6-module-is-installed

来源： https://stackoverflow.com/questions/48899148/how-can-i-tell-programmatically-if-a-perl-6-module-is-installed

来源： https://stackoverflow.com/questions/49814220/does-pattern-match-in-raku-have-guard-clause