This channel is intended for people just starting with the Raku Programming Language ( Logs are available at
Set by lizmat on 8 June 2022.
Nemokosch rf: where did you find the spec, then? 00:00
rf In the HTTP headers of any HTTP response 00:01
And there's an RFC for it somewhere I'm sure
Nemokosch this one?
ToddAndMargo "put" does not work either in binary mode 00:02
Nemokosch ToddAndMargo: try write 00:03
This spec
Looks like we found the same one on different websites
ToddAndMargo Type check failed in binding to parameter '$buf'; expected Blob but got Str ("¼ÐWå¿ñå?¸\x[1B]±\tï...) 00:04
rf Do$MyScrambleStr)
Instead of just passing the Str 00:05
ToddAndMargo my $MyScrambleBuf = $MyScrambleStr ); 00:07
No such private method 'throw-typecheck-element' on Blob
Nemokosch the error is not so nice but surely you can do better at converting a string into a blob 😛 00:08
ToddAndMargo gave the same error 00:09
Nemokosch rather look for a conversion method... like encode 00:10
ToddAndMargo I am trying to write a scrambled text file to a binary file.  spurt gives me a zero length file.  The string looks like this: ┬╝├ÉW├Ñ┬┐├▒├Ñ?┬╕\x[1B]┬▒\t├» 00:11
I need what is written to be exactly what is in the string.  No conversion.  It is a cypher 00:12
slurp read it back just fine, if i can get into the file to start with 00:13
Nemokosch if you want no conversion, you shouldn't read it as text in the first place
ToddAndMargo how do I get it from my string into something that I can binarily write the file? 00:15
Nemokosch rf: not sure if there is a module for that exact standard but you could consider taking a look at 00:16
ToddAndMargo Looking at my scramble module, I see I did everything as a bug and at the last moment converted it to a string.  So, I will turn it into two and give back either a string of a buf. 00:20
rf Looks like that module will do it 00:30
Thanks 00:31
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ToddAndMargo Everything is now bufs and binary.  And it is working.  Thank you all for the help!  signing off 04:10
Read Example:
   my $MyScrambleBuf =;  # the .new is required of a buffer
   my $FileHandle    = open "$WanIpFileName", :r, :bin;
   # enter number of bytes in the () or emply for all
   $MyScrambleBu     = $;
Write Example:
   my $MyScrambleBuf =;  # the .new is required of a buffer
   my $FileHandle    = open "$WanIpFileName", :rw, :bin;
   $MyScrambleBuf    = $FileHandle.write( $MyScrambleBuf );
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yabobay if i have a big long list, is it computationally expensive to create a list that's everything but the first 3 elements of the list? 12:23
Nemokosch I think copying a list is kinda expensive because lists aren't deeply immutable 12:29
codesections has been working on implementing deeply immutable lists that don't have to be actually copied
lizmat yabobay do you actually need that list to exist, or do you need that list to iterate over? 12:33
yabobay to iterate over
lizmat if the latter, then: (list).tail(*-3) would do the trick
yabobay if i put that in a variable what happens? 12:34
lizmat m: dd (1..10).tail(*-3)
camelia (4, 5, 6, 7, 8, 9, 10).Seq
lizmat if you put it into a variable *then* it will get copied
yabobay oh, ok
lizmat m: dd (1..10).skip(3) # another way
camelia (4, 5, 6, 7, 8, 9, 10).Seq
Nemokosch what if one binds a variable to it? 12:35
lizmat then you'd be binding to the Seq 12:36
Nemokosch that wouldn't copy but would it "do the right thing"?
lizmat which is fine, if you know what you're doing :-)
again, you would be binding to the Seq
and that by itself wouldn't do anything
m: my $a := (1..5).map(*.say); say "bound"; Nil for $a 12:37
camelia bound
lizmat you'd have to use the Seq in an iteratiing context 12:38
m: my $a := (1..5).map(*.say); say "bound"; $a.iterator.sink-all # basically what happens with the "for"
camelia bound
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yabobay remind me what binding does: if i edit something in the bound array, the original array also changes? 12:38
Nemokosch do Seqs get exhausted by one iteration? 12:39
yep 12:40
yabobay ``` 12:41
Type check failed in binding; expected Positional but got Seq (((65, 66, 67, 255), ...)
in sub bitmap2file at png2file.raku line 61
in block <unit> at png2file.raku line 70
getting this error when doing skip(3) on a list
Nemokosch the way I like to describe the situation is: when you bind a variable to something, the variable IS that something
ngl I find this kinda stupid... a Seq is not a Positional, only "PositionalBindFailover" 12:42
you could of course just use $ or \ (which always binds on initialization anyway) 12:43
or you could try .list but I wouldn't know if that "copies" 12:44
yabobay so using $ worked but it feels like this *isn't* one of those times where it's just me who thinks this is unnecessary
Nemokosch yeah no. What is the point of @ if basically all list operations produce a type that cannot even be bound to it 12:47
yabobay the point of @ is that it's for lists
lizmat yabobay code ? 12:48
yabobay ```pl 12:49
sub bitmap2file(@bitmap) {
# the first 3 pixels of the bitmap tell us how many bytes of
# information are stored in the last pixel. the rest of the bitmap
# is the actual information we want.
my $header := @bitmap.head(3);
my $contents := @bitmap.skip(3);
my $colorsThatAreActuallyInTheLastPixel = 0;
for $header -> @p {
if @p[3] == 255; # that's the alpha channel
say $ *.head(3);
that last line i just added right now. is that one expensive?
Nemokosch is nqp::isconcrete about reification? 12:53
I don't think it does anything you wouldn't want it to 12:54
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lizmat yabobay for @bitmap.head(3) { ... handle header }; for @bitmap.skip(3) { ... handle actual bitmap } 12:56
no need to copy anything, I'd say 12:57
yabobay i'm only doing it like that to communicate it to someone who reads the code (that someone will probably be me after i forget how it works)
also i thought this actually does no copying at all 12:58
Nemokosch well this doesn't
lizmat but the $contents variable, when iterated over, already skips the first 3 in bitmap, so why the .map: *.head(3) there ??
yabobay *inside* contents, there are other lists, of which i need only 3 elements 12:59
lizmat ok, when then you run into problems if you'd want to iterate over $contents more than once 13:00
Nemokosch *I take your brain to another dimension... pay close attention* 🎶
yabobay why? it's not modifying contents, is it?
lizmat m: my $a := (1..5).skip(3); .say for $a; .say for $a
camelia 4
The iterator of this Seq is already in use/consumed by another Seq (you
might solve this by adding .cache on usages of the Seq, or by assigning
the Seq into an array)
in block <unit> at <tmp> line 1

yabobay huh. 13:01
Nemokosch the irony is that this is asking for copying basically xD
lizmat now, if you would add .cache to the Seq, that's just basically copying for you under the hood
yabobay ok i think i might just do this using good ol' array indices?
lizmat depends
Nemokosch you can do slices I think 13:02
slices don't seem to copy, thank heavens
yabobay they don't? 13:03
Nemokosch m: my @funny = 1, 2, 54, 23, 13, 15, 34; say @funny[^3][2] =:= @funny[2];
lizmat m: my @funny = 1, 2, 54, 23, 13, 15, 34; say @funny[^3][2] =:= @funny[2];
camelia True
yabobay huh 13:04
m: my @funny = 1, 2, 54, 23, 13, 15, 34; say @funny.head(3)[2] =:= @funny[2];
Nemokosch 😂
lizmat m: my @funny = 1, 2, 54, 23, 13, 15, 34; say @funny.head(3)[2] =:= @funny[2];
camelia True
Nemokosch the difference is that head returns a Seq
lizmat is starting to feel like a bot now :-)
Nemokosch [^3] returns a List
yabobay do those have any practical difference ? 13:05
Nemokosch lizmat: fyi those evals do run here, they just aren't sent over
lizmat aha... ok
Nemokosch well, as you can see, one is a Positional and the other isn't 13:06
one gets exhausted after one turn of iteration, the other doesn't
I think [^3] actually does copy, in some sense. It creates a very shallow copy where all the elements are bound to the sufficient positions 13:07
but really, I'd assume that's the best it can get without immutable data structures
yabobay this is kind of a significantly more stupid question, but i have the buf8 i wanna save to a file in a variable, what should i name the variable? i want something v generic. right now i have it called $stream 13:09
lizmat "There are only three hard problems in computer science: Cache invalidation, naming things, and off-by-one errors" 13:10
Nemokosch two problems 😛 13:11
$payload? $content, possibly $binary-content? 13:12
yabobay well we already have $content
there truly cant be a more generic variable name than that
fileData is another pretty vague one i could use 13:13
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p6steve I'm not a raku core guy, and I shun esoterica like the MOP, but I think I know raku from 'coderland' pretty well having coded in it for 5 years or so ... it's worrying me that here on raku-beginner there is a very high % of stuff that makes me scratch my head (for example in the dialogue in the last couple of pages, I have been lost in Seq, Slip, Arrays, binding, slices, skip, rotor, nqp, and so on) ... no 14:21
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lizmat well, all of that is under the hood, mostly 14:22
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lizmat and I wouldn't call explicit binding a beginner's feature for sure 14:22
p6steve If you read to the end of my recent blog post you will see that I quote two bits of advice that I picked up and regurgitated... (i) do not use $ with any kind of list unless you want a suprise! (ii) while raku also gives us Seq and List types, you want to use Array unless you are an expert 14:23
sooo --- may I v. gently suggest that we move over to the main raku channel when we lift the hood??? 14:24
sorry to nag 14:25
lizmat no worries :-) 14:27
Nemokosch regarding the communication channels... tbh I think it's only worth talking about this if we are "serious about it". I'm still thinking about making a case "against IRC" (more accurately, pro something-real-time-that-has-forum-like-features) 14:33
for IRC where users are disposable entities and there is no central history, it absolutely feels like dialogues are the units of communication, hence why should it matter what others talked about "pages ago" 14:35
now the rare thing happened that Discord users were more active and therefore it might feel a little different 14:36
but the first-class channel is still the IRC channel as far as I'm concerned, it's just a fun fact that we join via discord 14:37
p6steve seems to me from other groups I am in that Discord is a good compromise (since we have bridge to IRC) perticulalry for beginners / newcomers who want to dabble (as I do over in Rust, Python and Polars land)
Nemokosch the problem with Discord is mostly the ethical part with FOSS in mind
p6steve don;t know if that counts as "forum features"
ethical++ 14:38
Nemokosch I suspect many users, especially "power users", just wouldn't be willing to move to discord.
or Slack, for that matter 14:39
p6steve personally I would weight "ability-to-attact-newbies-ness" above "hatred-of-corporate-greed-and-controlity"
(but that's just me) 14:40
Nemokosch same for me but it's easy to say when I have traded these values a long time ago anyway 14:42
Kaiepi i really wish something other than discord would be the popular means of chatting nowadays, but i also hate forums and mailing lists
irc i put up with ig
p6steve discord is quite of the moment and does help raku seem a bit cooler 14:43
Nemokosch for example, I'm the kind of person who is happy to use a Google/Microsoft/FB login everywhere, rather than register to individual services
that's why Mastodon sort of stuff was immediately unappealing 14:44
I get frustrated by new identities beyond rational
p6steve yeah, but geeks are a high % of disord and a low % of mastodon (or soon will be)
I will take some pain to kick that Tesla guy in the teeth 14:45
Nemokosch 😂
ngl I wouldn't shed a tear over the Twitter community but we're kinda pushing far 14:46
anyway, I'm sure somebody has thought about this before: why not make something like discord/slack, something that is easy to use and isn't corporatist spyware?
something that functions similar to Mastodon but for this real-time-forum functionality 14:47
p6steve i would only use it if its build on cro
Nemokosch 😂
lizmat I'm surprised it would be ok to use a MS/G/FB login
I have none of them, because of corporations lurking 14:48
Nemokosch Matrix came up every now and then, I don't know what it's like in practice
avuserow also named something else, lemme check 14:49
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After a quick glimpse, I'm afraid Mattermost would still be too alien from the requirements and demands of this community 14:50
lizmat it's nice, but it's also a single corporation
what happens with all of your dialogue when it goes down, or gets bought by MS / Meta 14:51
Nemokosch I think at the end of the day, it's good to have a server one way or another, central at least regarding the community. Something that messages do go through and can do logging and stuff like that. 14:53
also, something that manages identities in a richer way IRC channels are usually set up. Something that I really miss from discord is the concept of roles - they can manage not only your permissions but also put you in a mentionable entity, hence opt into something you care about/identify with 14:56
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Rog I do have in the works a chat client that would be a bit more like discord but with self-hosting 19:45
But that’s who-knows-how-many months or years away
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jaguart p6steve: nice 🙂 22:16
I have a question about how you lay out your dev work. I has App1 and App2 in dev, they use lib1 and lib2 modules - which I will probably have to tweak too - each thing is going into it's own distribution. **How do you set up your dev / early testing directory structure? ** (and associated RAKULIB ) I'm thinking a dev area with links? What about the meta6's? 22:19
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