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This channel is intended for people just starting with the Raku Programming Language (raku.org). Logs are available at irclogs.raku.org/raku-beginner/live.html Set by lizmat on 8 June 2022. |
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| Salizer | Barely started reading and learning about Raku, and I've gotten confused about bracket/brace usage. | 14:43 | |
| For example I see N different ways to initialize arrays. 1, 2, 3; (1,2,3);[1,2,3]. What is the difference, if any? | 14:44 | ||
| On beforehand, thank you. | 14:45 | ||
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| antononcube | @Salizer First, I understand your confusion. | 15:59 | |
| Raku, has a style that allows grammar-nazi to grammar-naz, but otherwise the rest can do their "loose" specification. | 16:01 | ||
| It is related -- but not complitely explained -- by the principle "there is more than one way to do it." | |||
| Now, more concretely, if you say something like my @arr = [1, 2, 3] someone can say that the square brackets are redundant -- we have indicated with the sigil @ that we assign to an array, hence, we can just list the elements separated with a comma. | 16:04 | ||
| In Raku arrays are different from lists -- lists are indicated with parentheses. | |||
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| Salizer | Got disconnected, but so far thanks for the info (saw through log). | 16:08 | |
| Biggest confusion so far, but what also makes it interesting, with Raku is the N different ways of doing stuff. | 16:09 | ||
| lizmat | fwiw. the reason my @arr = [1,2,3] works is because of the single argument rule | 16:10 | |
| docs.raku.org/language/list#Single...ument_Rule | |||
| antononcube | It seems I use Raku a lot lately, but I am not recommending it much. (Everyone at work is scared from my usage of it...) | ||
| lizmat | m: my @arr = {1,2,3],[4,5,6]; dd @arr # **NOT** [1,2,3,4,5,6] | 16:11 | |
| camelia | ===SORRY!=== Error while compiling <tmp> Missing block at <tmp>:1 ------> my @arr = {1,2,3⏏],[4,5,6]; dd @arr # **NOT** [1,2,3,4 expecting any of: statement end statement modifier statement m… |
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| lizmat | m: my @arr = [1,2,3],[4,5,6]; dd @arr # **NOT** [1,2,3,4,5,6] | ||
| camelia | [[1, 2, 3], [4, 5, 6]] | ||
| antononcube | And surprisingly (or not so much) the principle "there is more than one way to do it" confuses and scares a fair amount of programmers. (Data scientists...) | 16:12 | |
| I assume the "single argument rule" is in Perl too, right? | 16:13 | ||
| (Well, of course -- I remembered the sub arguments in Perl...) | 16:14 | ||
| lizmat | no, the single argument rule is *not* in Perl | 16:19 | |
| in Perl everything is flattened | 16:20 | ||
.oO( in my recollection in any case, it's been 10+ years since I really did anything with it) |
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| antononcube | @lizmat Good to know! | ||
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| rcmlz | my favorit solution to initialize arrays of strings is: my @a = <q w e r t 1 2 3>; | 16:37 | |
| or in this case @a = 'qwert123'.comb maybe, just because we can :-) | 16:41 | ||
| librasteve | Salizer: great question. My answer is (i) take a quick look at the Array typegraph here docs.raku.org/type/Array#typegraphrelations (all raku data types are classes and they form a class / role hierarchy via raku OO) - so an Array is a fancy kind of List which does role Positional and role Iterable and some other methods that extend the List methods (push, pop and so on), (ii) then take a look at | 17:15 | |
| the definitive guide to Sequences, Lists and Arrays here docs.raku.org/language/list ... you may need to read it a couple of times to get all the aspects - I would highlight [a] the comma is the List literal builder (in raku round brackets are mainly just for avoiding ambiguity), [b] the square brackets [] are the Array literal builder, [c] the Single Argument Rule (which makes for behavior as the programmer | |||
| would expect) and [d] the notion of List Assignment when assigning stuff to an @ sigiled variable. | |||
| The way I look at it, Raku is basically a set of "micro-features" that compose to make a set of familiar capabilities for exerienced coders and for novices --- so you can stay in the shallow end of the pool and just go my @a = [1,2,3] and that's an array just like the one you would get in perl and very similar to most other languages ± the @ sigil. Nothing scary and actually a lot of raku syntax is really | 17:23 | ||
| nice for shallow end programming (I am thinking of the has $.attr syntax which lets raku OO really easy with say $class.attr and for iteration etc, etc. | |||
| The raku guide raku.guide is imo a good level of intro that keeps mainly in the shallows and has some good examples of typical usage .... and I am sure you will already have tried the repl and running some code examples ... personally I am much more scared of Rust which barks at me if I put one foot wrong, the raku syntax / semantics is much more forgiving and quick to write something that just | 17:31 | ||
| works. [otoh, there are many threads in this beginner channel that go deep and do look scary] | |||
| lizmat | librasteve do you think mods should intervene if the threads go to deep for this channel ? | 17:36 | |
| librasteve | I would like to think that folks are capable of self-policing ... if not, then after a gentle reminder, yes | 17:39 | |
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| Brian11 | Hi, I am working with unit tests and I would like to capture the output of a failed assertion. For example `is(1, 2)` fails, but how would I capture the text printed to the console that describes the failure? | 19:58 | |
| librasteve | Brian11: Hi - are you OK to let the test die, or do you want to run a try block and capture the output? | 20:08 | |
| m: use Test; is(1, 2), 'ok'; | |||
| Raku eval | not ok 1 - Exit code: 1 WARNINGS for /home/glot/main.raku: Useless use of constant string "ok" in sink context (lines 1, 1) # Failed test at main.raku line 1 # expected: '2' # got: '1' | ||
| Brian11 | Yea, I have added a try block. But it doesn't seem to capture the failure in catch. | 20:12 | |
| Basically I am trying to implement a test runner and want to collect the output. | 20:13 | ||
| briandouglas_71953 | Hi, Joined via discord now. | 20:14 | |
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| To give some context I have implemented some wrappers around the testing lib. But rather than write a custom exception (...maybe I should) I was wondering if I could "catch" the output from a failed test. Test wrapper. raku use Test; role Comparator { has $.given is rw; method to-be($expected) {...}; method to-be-true {...}; method to-be-false {...}; method not {...}; } class | 20:22 | ||
| NegativeComparator does Comparator { method to-be($expected, $desc = "") { isnt($.given, $expected, $desc); } method to-be-true($desc = "") { isnt($.given, True, $desc); } method to-be-false($desc = "") { isnt($.given, False, $desc); } } class PositiveComparator does Comparator { method to-be($expected, $desc = "") { is($.given, $expected, $desc); } method to-be-true($desc = "") { is($.given, True, $desc); } | |||
| method to-be-false($desc = "") { is($.given, False, $desc); } method not { NegativeComparator.new(given => $.given); } } Developer API for context. raku describe("Basic test suite", -> { it("should know 1 is 1", -> { expect(1).to-be(1); }); it("should know True is true", -> { expect(True).to-be-true; }); it("should run multiple assertions", -> { expect(1).to-be(1); expect(True).to-be-true; | |||
| expect(True).not.to-be-false; expect(False).to-be-false; expect(False).not.to-be-true; }); }); | |||
| librasteve | @briandouglas_71953 I've taken a look and cannot quite figure this out ... heres the source of is github.com/rakudo/rakudo/blob/5fb6...kumod#L176 | 20:31 | |
| looks like Test is using try internally and I don't know enough to see how to extract the $! error textually | 20:32 | ||
| i have succeeded with an async pattern like this before my $proc = Proc::Async.new: <cargo build>; $proc.bind-stdout($*ERR); my $promise = $proc.start; await $promise; | 20:33 | ||
| briandouglas_71953 | Yea, that makes sense. I will try that. I'll do deep dive on the source code also, I might learn a valuable nugget. | 20:37 | |
| librasteve | here's a slightly better example from the docs # command with arguments my $proc = Proc::Async.new('echo', 'foo', 'bar'); # subscribe to new output from out and err handles: $proc.stdout.tap(-> $v { print "Output: $v" }, quit => { say 'caught exception ' ~ .^name }); $proc.stderr.tap(-> $v { print "Error: $v" }); say "Starting..."; my $promise = $proc.start; # wait for the external program to | ||
| terminate await $promise; say "Done."; | |||
| docs.raku.org/type/Proc/Async | |||
| briandouglas_71953 | Oh nice, that looks good. Thanks @librasteve | 20:39 | |
| antononcube | @Biran Use LLMs. | 20:40 | |
| librasteve | or ... | 20:41 | |
| use Test; use MONKEY; my $txt = EVAL qq{is(1,2), 'ok';}; say $txt; | |||
| antononcube | (That is a marketting hint / advice...) | ||
| (Mine / not Steve's ...) | |||
| librasteve | m: use Test; use MONKEY; my $txt = EVAL qq{is(1,2), 'ok';}; say $txt; | ||
| Raku eval | not ok 1 - (False ok) Exit code: 1 # Failed test at EVAL_0 line 1 # expected: '2' # got: '1' | ||
| librasteve | ^^ if you are OK to use EVAL this is probably easier | 20:42 | |
| antononcube | I wonder if the Gherkin hookup to Raku would work for Brian's use case(s). | 20:43 | |
| Mmm... By "Gherkin hookup" I meant "Cucumber hookup." | 20:45 | ||
| This one : raku.land/cpan:ROBERTLE/CucumisSextus | |||
| librasteve | lol | ||
| antononcube | It would be interesting to see would ChatGPT or Gemini comes with a working solution. (Same or different by Steve's.) | 20:50 | |
| librasteve | I tried ChatGPT first --- this is too esoteric for that to work | 20:54 | |
| @antononcube I was inspired to try Jupyter::Chatbook on my mac by Massa Humberto hachyderm.io/@massa/112476922875567264 | 20:55 | ||
| BUT, even though I jumped through the Net::ZMQ hoops, I do not get the raku kernel, only python3 (both zef install Net::ZMQ and zef install Jupyter::Kernel tests passed | 20:56 | ||
| (sorry - seems like Issues are off on the Jupyter::Chatbook repo so I cannot report there) | |||
| antononcube | Issues Shouldn’t be off ! | 21:08 | |
| The Raku kernel might tucked in under a generic group “Jupyter kernel”. | 21:09 | ||
| What happens when you run the Raku kernel in terminal / console? | 21:10 | ||
| Here is the succession of Kernel selection in VS Code. | 21:20 | ||
| cdn.discordapp.com/attachments/768...c08b8& | |||
| cdn.discordapp.com/attachments/768...89ea0& | |||
| cdn.discordapp.com/attachments/768...27944& | |||
| I have enabled "Issues" for "Jupyter::Chatbook". | 21:50 | ||
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| briandouglas_71953 | Wow, it's actually quite annoying that I can't capture the output of a test assertion. It makes things awkward indeed. | 23:18 | |
