Foone🏳️⚧️
I'm writing rust without fully understanding the language. Pray for me.
Actually I guess that's true of most language I program in? Like, I'm sure there's some obscure python syntax or behavior I can't remember, despite calling myself a python programmer and having done it professionally for many years.
but my point was more that I barely know any rust. there's entire parts of syntax I don't understand yet. but I'm coding anyway!
Foone🏳️⚧️
I just had to look up why "str" didn't work (I mean "String", a different type entirely)
Foone🏳️⚧️
@114N and I only know two! So many more string types to learn!
114N
@foone Oh god the rust string situation is admittedly crazy and I say this as a rust programmer
Like I get why they need the 6+ different string types but damn they have more than 6 different string types
Foone🏳️⚧️
oh you have to define your return types. I didn't know that. I was returning the wrong ones and the compiler was mad
Foone🏳️⚧️
wait is this function returning the Result that Some of it is Ok?
Foone🏳️⚧️
I'm not entirely sure I am sober enough to understand how Results interact with Options<>
Result is an enum that's either Ok or Err, and Option is an enum that's either None or Some.
Is it that for Result, there's parameters with both Ok and Err, but with Option, there's no parameters with None?
And you just use them differently?
Foone🏳️⚧️
I think I understood that but now I'm trying to understand the anyhow crate. you can attach contexts to function calls so that their errors are better commented? I'm missing something here
Foone🏳️⚧️
oh, there's a foo() function returning anyhow::Result, so other code can do foo().with_context("trying to foo")
so when the anyhow::Result from foo() gets printed out on the console, it can say something like "Failed: while trying to foo"
Foone🏳️⚧️
and with_context() is anyhow::Result.with_context, and it returns itself. So you can chain it like that.
Foone🏳️⚧️
the docs just told me I can manually customize my panic and I have very little understanding as to what that means
abrasive
@foone if a doctor offered me the chance to customise my panic you best believe I'd be all over that
Foone🏳️⚧️
ugh. I slept for like 9 hours and the Rust code is still here
Foone🏳️⚧️
and I still don't understand it
Foone🏳️⚧️
anyway the part of the puzzle that I think I inadvertently left out of this thread is that I'm starting out learning rust by modifying an existing rust program, not in writing anything my own.
So there's a lot of "how the fuck does this work?" and having to read the source until I figure out what keywords I need to google
Foone🏳️⚧️
which is a lot easier when it's a word like "Result" or "anyhow with_context" and not "?"
Foone🏳️⚧️
(I think I figured out ? now, you don't need to provide any help. that was just an example)
Foone🏳️⚧️
it's working and I am learning rust, it's just very much the same vibes as learning to swim by having your grandpa fling you into the deep end
Foone🏳️⚧️
@immibis to be honest I'm over here on mastodon trying to figure out rust because my normal social media (tumblr) is just people talking about shooting trump
immibis
Foone🏳️⚧️
I should probably figure out what these & symbols mean
Foone🏳️⚧️
is there any ide that's recommended for doing rust? I'm currently just using Sublime Text which has some syntax highlighting but not much else.
Is there good support in VS.code or something?
Foone🏳️⚧️
oh now now I have to understand how implementing iterators works
Foone🏳️⚧️
okay apparently the problem is that this code implements iterator for "foobar", but not for "&foobar"
I'm not sure what the fuck that means
Foone🏳️⚧️
but I do like that it's "for more information, run "rustc --explain E0277"
I grew up on the TRS-80 which just gave you ?ER when something was wrong. What, specifically, was wrong? Fuck you, that's what.
Foone🏳️⚧️
if you look closely you can spot where the article is supposed to be
mhoye
@foone I would sometimes like to be able to turn on something like “student’s syntax highlighting” in a language I don’t know, that simply explains the operator or form I’m mousing over to me like it would to somebody who doesn’t know the basics yet.
Foone🏳️⚧️
@mhoye yeah, that'd be great! like a quick way to say "explain this like I'm 5", pretend I don't know this language and explain what the fuck is going on. You're a compiler, you should know!
Foone🏳️⚧️
type Item = &'a str;
this is valid syntax and not someone sneezing into a keyboard?
Foone🏳️⚧️
okay I think the problem is something like: this code originally implemented IntoIterator which was fine because it was backed by a std::vec so it could just use that iterator.
but now it's not a std::vec so it doesn't work.
except it still kinda is. so... it doesn't work
Foone🏳️⚧️
@Jhynjhiruu yeah I'm heavily using the official docs and rust by example, I was just searching in the hopes someone had explained my specific issue
Jhynjhiruu
@foone https://doc.rust-lang.org/stable/std/iter/index.html#implementing-iterator
Use the standard library documentation where you can; it's great. https://docs.rs/std/ is a shortcut to it.
Foone🏳️⚧️
now I gotta figure out what a tuple struct is.
it seems to be a regular struct except your fields don't have names?
Foone🏳️⚧️
@onelson ooh, handy. I'll have to look into that. Thanks!
Owen Nelson
@foone fwiw I also use Sublime but I use a combination of RustEnhanced (for basic syntax highlighting) and the rust-analyzer LSP package for the rest.
Foone🏳️⚧️
sometimes I worry I'm not awake & sober enough to understand this.
sometimes I worry I've never been that awake and sober. I don't know if I've ever been so knurd I could actually understand this
Foone🏳️⚧️
and someone mentioned cargo-mommy to me and now I'm having my brain broken by that.
PROGRAMMING IS HARD ENOUGH ALREADY WHY DID YOU HAVE TO GO AND MAKE IT HORNY?
Foone🏳️⚧️
@gregly I should install a klingon module so instead of compile-success I get "qa'pla!" and when my code doesn't compile it calls me a petaQ
Determination G. Schadenfreude
@foone I’ve joked before that Rust’s use of ‘a makes it look like Klingon to me 😅
Foone🏳️⚧️
@canteen in python, sure. I think it's pretty similar in rust, but there's also tuple-structs which don't seem to be all that related to tuples
canteen
@foone isn't a tuple just an immutable list?
Foone🏳️⚧️
okay, enough people being horny about programming languages and shooting at former presidents.
this code still can't iterate
Foone🏳️⚧️
so (and I'm writing this primarily to rubber-duck my own understanding of it, rather than specifically asking questions, though feel free to speak up if you think you can help):
I have a tuple struct called "Commands" that contains an std::vec of "Command" structs.
I'm passing this into a function, as a reference. so the function gets a &Commands parameters.
It then tries to do "for command in commands" to iterate through the contents of the Commands struct, but it can't.
Foone🏳️⚧️
originally this code had the IntoIterator trait implemented, but that doesn't work. Because (I'm reasonably sure) we don't have a Commands, we have a &Commands.
Foone🏳️⚧️
because defining an iterator (or IntoIterator) for Commands is different than defining one for &Commands
Foone🏳️⚧️
so... presumably I need to implement an iterator/IntoIterator for &Commands.
Not really sure how to do that, but I can hopefully figure it out
Foone🏳️⚧️
"in the trait associated type is declared without lifetime parameters, so using a borrowed type for them requires that lifetime to come from the implemented type"
that error makes sense. I just don't know how to do that
Foone🏳️⚧️
@tedmielczarek yeah that might be the way to go. it isn't as "elegant" but it does solve my problem
Ted Mielczarek
@foone just call .iter() on the Vec: for command in commands.iter()
Foone🏳️⚧️
I didn't figure that out. I instead just explicitly called iter() on the reference which I defined to call iter() on the std::vec. So now i'm on to other, weirder problems
Foone🏳️⚧️
now I'm trying to figure out the following:
I have a vector of Commands (which is an enum). Some of them are Include commands. I need to go through the vec and replace the Include commands with the Commands from the item they're supposed to Include.
So I need to iterate through the vec and do something special when the command is an Include vs something else.
Foone🏳️⚧️
which sounds like a match but I need to run a block of procedural code in response to it being an Include, not just return a value
Foone🏳️⚧️
so I need something like:
for command in commands.iter(){
if type(command) == Include {
//do some stuff here
}
}
but I don't know the syntax for "if this enum is this type" or if this is a remotely reasonable pattern for rust code
Foone🏳️⚧️
ahh there's a matches! macro
Foone🏳️⚧️
@leean00 There are! I don't think they'd be useful here, as the ordering of the Commands is important
Andrew Leer
@foone um, are there hashmaps in rust? Or are those too immutable for that language?
Foone🏳️⚧️
and if-let.
I'm clone()ing everything these days. I'll make this more performant and efficient later
Foone🏳️⚧️
oh no, I'm borrowing a moved value!
I'm not really sure what that means or why it's a problem
Foone🏳️⚧️
okay my code for the Include nonsense is actually working now.
I have .clone() in 90 places and probably only need it in one or two
I shall try to fix this later
Foone🏳️⚧️
@StompyRobot right, that's what I did.
Peaceful Assembly Robot
@foone
Typically you'll build a new vec, rather than mutating the original
Nova🐧✨
@foone afaik the rust compiler optimizes out unnecessary clones so just run it through clippy and if it doesn't warn you then it's all good
Foone🏳️⚧️
@technobaboo good to know!
I don't know what clippy is but I can probably find out
Foone🏳️⚧️
this code currently generates SVG files.
I don't really want to look up how to make it do that better, and I don't need that ability, so now I gotta figure out what to do next. I think I might implement a generate-to-text feature to debug/implement everything before I try generate-to-bytecode? I don't want to have to observe my results in a hex editor
Foone🏳️⚧️
@technobaboo thanks!
Nova🐧✨
@foone it's the rust linter, ties into rustfmt and all so you can specify exactly how you want your code to lint inline and it can even fix most non-idiomatic things for you! might help you learn rust idomatics
Foone🏳️⚧️
I'm having to touch parsing code.
it hurts but I'm managing
Foone🏳️⚧️
I wonder if I can compile rust code for DOS
Foone🏳️⚧️
OH GOD NO NOT THE BRAZILIAN FLAG
the complexity of the Brazilian flag is half the reason I'm learning Rust!
Misty
@foone Zed has excellent builtin support; it’s what I’ve been using.
Foone🏳️⚧️
ok as I try to figure out how the parser works, I discover that I haven't properly implemented includes.
because right now this is resolving includes after parsing, but variables are resolved during parsing, but you should be able to include a flag for its variables.
Foone🏳️⚧️
so I'm going to have to somehow move the include handling into the parser, not after it. Nasty.
Foone🏳️⚧️
anyway right now I'm trying to figure out parsing variable declarations.
There's existing code that handles some basic versions of it, but the problem I'm currently facing is that there are multiple types of values in variable declarations. like:
$foo=42
$bar="hello"
$center=(320,240)
$background=RGB(255,0,255)
and I have nom-parsers that can handle parsing integers and strings and points and colors, but now I need to handle "it could be any of them"
Foone🏳️⚧️
and I've got an enumeration that can be any of them but I'm not sure how to tell nom about this. I can't do alt(integer, string, point, color) because each of those functions returns a different type
Foone🏳️⚧️
I solved it by writing wrapper functions that are basically identical. there is probably a way to make this more reasonable using generics or a single function with a match, but for now... it's inelegant but presumably at least functional
Foone🏳️⚧️
handling errors and types are the two main complexities of rust that I've run into so far
I'm currently trying to handle the type of errors, so I'm completely screwed
Foone🏳️⚧️
I am making some kind of progress. I handled my Test file.
variable references are now handled enough to not need to hardcode any of the metadata.
Next step is to actually handle looking up variables
Foone🏳️⚧️
because you're supposed to be able to use this syntax:
$red=RGB(255,0,0)
Rectangle (0,50), (200,60), $red
The first line works. The second doesn't yet.
Foone🏳️⚧️
this was working before, and I broke it. But I'm breaking it to be more generic
Foone🏳️⚧️
because the previous implementation was color-specific.
But you should be able to do this too:
$red=RGB(255,0,0)
$startpoint = (0,50)
Rectangle $startpoint, (200,60), $red
Foone🏳️⚧️
I've been yelling at rust for 10 hours today. I think that's enough for now.
RetroSwim
@foone Could be worse.
"On Error Resume Next" worse.
🙃
Foone🏳️⚧️
@retroswim I used to be a VB programmer! I know the pain!
Foone🏳️⚧️
now I'm trying to figure out how to handle the type system for my language I'm implementing in Rust, without having to fight the type system OF rust.
Foone🏳️⚧️
since every command in VFL has specific types it takes for each argument. And right now this is represented by the enums for each of the commands taking those types of arguments.
Foone🏳️⚧️
but right now I'm trying to add variables back into the language.
and because of where these enums are used in the parser, I'd need to change all those types to be ReferenceOrLiteral, losing that type info.
Foone🏳️⚧️
maybe I should learn how generics work?
Then it could be ReferenceOrLiteral<String>,
Wez Furlong :terminal:
@foone not sure if this actually is helpful here, but maybe look at Cow<str>?
Foone🏳️⚧️
@wez I don't think so. To be clear, these are references in VFL, the language I'm implementing, not references in rust. So this fixes a problem at the wrong layer.
Foone🏳️⚧️
I skipped generics. now I'm just trying to write a generic resolve function that takes a ReferenceOrLiteral and turns it into a TypedValue, but I'm not sure how to make the references work. I'm gonna have to understand that lifespan syntax
Foone🏳️⚧️
wasn't an issue!
and now I have at least one command working with proper variable indirection.
Foone🏳️⚧️
me: I don't need to support $foo=$bar syntax. You can only assign variables with literals, not other variables.
also me: I wrote one of the example files using that syntax
Foone🏳️⚧️
okay that wasn't too hard to fix.
Foone🏳️⚧️
whoops I figured out how to implement fonts in my flag language
Shambolic Matter
@foone A flag language should be good for multithreaded programming because of semaphores
Foone🏳️⚧️
@xorn hah!
Foone🏳️⚧️
my language should now be case insensitive.
except for variables. right now those are case-sensitive.
Foone🏳️⚧️
now I'm trying to figure out how to assign a fixed-length string, and failing.
I can turn "hello world" into a [u8] by doing .as_bytes() but I can't assign that to a [u8;11]
Foone🏳️⚧️
apparently the magic I need is .try_into()
Foone🏳️⚧️
so now I gotta finish implementing a binary writer for the FLG bytecode, which is only really documented in the kaitai struct code I used to read it before, which is also wrong, because I've changed some things about the language since then. I think.
Foone🏳️⚧️
that's enough rust for one day
Foone🏳️⚧️
now I gotta figure out how to do an enum that works like a C++ enum. like, I need it to have integer values.
rust's enums where they can contain all kinds of data per value is neat, but I need the enum to be a 0x04
Foone🏳️⚧️
this is easy, just stick =0, =1, =2 after the enum names, but the trick is getting the binary-writing crate I'm using into actually writing them out, since it doesn't really know what to do with enums
Foone🏳️⚧️
@str4d Sure.
str4d 🛡️
@foone I enjoy your long discovery threads like this! Do you want Rust pointers from other people in this one? (I don't want to drop references to the relevant documentation unless you actually want them.)
Foone🏳️⚧️
str4d 🛡️
@foone which crate are you using?
Foone🏳️⚧️
That's all fixed. just defined a preprocessor to turn the enum into an integer (u8) that BinWrite knows how to write
Foone🏳️⚧️
One thing I'm not yet comfortable yet in rust is writing rust-style code. I keep trying to write very pythonic DRY code and rust's type system is like "no, don't".
and I end up having to write it more like C++, which results in a bit more copy-pasted boilerplate than I would be happy with in python
Foone🏳️⚧️
this is supposed to be the rainbow flag. clearly something is /slightly/ wrong
Foone🏳️⚧️
ahh!
the way my rectangles work is backwards: I thought it was point-1, point-2, and then the color.
nope! I put the color at the beginning, because basically every command has a color. so I need to either fix how my code writes it, or change how my code reads it
Foone🏳️⚧️
BINGO
Foone🏳️⚧️
okay so now I can do a full path from a VGA Flag Language (VFL) file, into the rust code, which compiles it into bytecode, which the vgapride-bytecode branch can read.
At least for rectangles.
So I need to implement ellipses and polygons and lines and crabs, then the same in the vgapride-bytecode branch, then port that BACK to DOS.
but this is a major step.
Foone🏳️⚧️
@wasamasa not yet. There's a doc here with some info on how the language works:
https://wiki.foone.org/w/VGA_Flag_Language
and some example files here:
https://gist.github.com/foone/11087057c4cf49c93212045e1e7e2b44
(the jewish one is wrong: the #include should be a filename, not a flag name)
Tunapunk
@foone Can't really make sense of your writings on VFL, bytecode and so on, but is any of that code online? Kinda tempted to port the flag generation parts to Emacs and having machine-readable flag definitions sounds better than rewriting the C++/BASIC code I've found on GitHub so far.
Foone🏳️⚧️
@Jhynjhiruu BinWrite doesn't seem to, but I'll have to check out BinRW. Thanks!
Jhynjhiruu
@foone BinWrite (or, certainly, its rewritten replacement BinRW, which I think is mostly drop-in) supports writing enums directly.
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