I’d much rather see a pr to add a version that works on arbitrary sequences

(struct foo (a)) defines a basic constructor function foo where you need to supply all the parameters for all the struct fields.

What @laurent.orseau means by a “smart constructor” (I believe) is, you just also define your own function (say you call it make-foo) that has any fancier behavior you want. Such as default parameters. Keyword parameters. A contract, or, manual validation. And so on.

I think @samth meant “unnecessary” more than “unhelpful”. All those things can be helpful. But you can handle it yourself, it doesn’t need to be baked into the core struct.

Of course if you do this kind of thing a lot, you can write your own “define struct” macro that defines both a struct and its fancy-constructor.

I think various people have done this. Various opinions how.

@jestarray @kellysmith12.21 ^

I specifically mean the default value feature that actually exists is unhelpful

A different feature, or a way to create smart constructors, would be useful, and many exist

The existing feature of struct is only useful for mutable fields that will only ever be set by a client not constructing the struct

Is there a way in a #lang scribble/manual file to hide some of the for-label bindings, so that @racketblock doesn’t hyperlink them?

only-in ?

except-in ?

I didn’t require any particular bindings though; these are (I think) coming from the #lang line itself

Ah. Tricky.

Don’t know.

@blerner I don’t think that’s true. If you use #lang scribble/manual without any for-label, then nothing will be linked. You need to (require (for-label racket/base)) explicitly to at least get built-in bindings.

yeah, after tracing through our imports some more, it looks like there in fact was a required library for-label that I hadn’t noticed. now that I see it, I can except-in eliminate the parts I don’t want

Could you somehow use a dummy module that shadows the bindings you don’t want?

Ah nvm

Is it a bug that build-path/convention-type cannot construct a Unix-style path when running on Windows?

yeah, was going to comment on the Pollen issue that you might want to report the problem lol

for pairs i need '(0 . (1 . 2)) where the 2nd element is a pair and the first is a value

but racket turns that into '(0 1 . 2) …

i need the parenthesis there for the 2nd element because the serializer to a rust struct requires: (name . ( (first . "bob" ) (last . smith))) the first element to be the name of the field, and the second to be the value

@jestarray The parentheses are implicit, however, you could write a custom print function to keep them.

im unsure how to go about doing so…

Oh, it’s for a serializer? That’s the format that needs to be read in?

yeppers. #[derive(Serialize, Deserialize, Debug, PartialEq, Eq)] struct Person { name: String, age: u8, }; // always in the format of (symbol . value). Trying to get (symbol . (symbol . value)) e.g (name . ((first . "bob) (last . smith))) working but racket excludes the parens needed let joanne: Person = from_str("((name . \"Joanne\") (age . 23))").unwrap(); https://docs.rs/serde-lexpr/0.1.1/serde_lexpr/

Ah, I see.

In that case, I would suggest defining a Racket struct to represent a Rust struct. Then, you can define a function to serialize it.

I’ll write up a quick example.

gonna try to see if i can get it to print pairs with the parens first… the docs on it is a bit scruffy…

This function will print a list to the provided output-port, while keeping parens and middle dots: (define (print-pair/parens pr [port (current-output-port)]) (fprintf port "'(~a . ~a)" (car pr) (let loop ([val (cdr pr)]) (if (pair? val) (format "(~a . ~a)" (car val) (loop (cdr val))) val))))

thanks, ill give it a shot

so close yet so far to near zero friction….

(If you don’t want the leading quote, then that function can be simplified.)

Treating (a b . c) and (a . (b . c)) as equivalent is one of the things s-expression formats typically have in common. I bet serde-lexpr would accept either one.

That being said, it’s good to write explicit serializing code in situations like this. If Racket and serde-lexpr do turn out to differ on some aspect of the s-expression syntax, trying to rely on Racket’s write will only get you so far.

i was using print because it initially gave me the least resistance but now write is turning out better now

just have to replace a few things

i could very easily swap this out with json which has a lot more work put into rust serialization and deserialization libs but ill mucking everything to s-expressions for consistency since the scripting language for my game will probably try to integrate racket or some scheme