Using Builder methods?

[yaleman]

I'm trying to use Apple's AppStore Connect spec and some of the requests have ~50 fields, so I enabled builders. There doesn't seem to be any way to actually instantiate a builder because there's no new/default/whatever method, and all the fields are marked private, so I can't instantiate it either way.

Is there a trick I'm missing?

[yaleman]

Never mind, found that they're a function of the client, which ... was rather confusing.

[lightsofapollo]

🤔 what's your take on a better way to expose this? Open to changes particularly before 1.0 in the design of the clients.

[yaleman]

Given a made up structure, something like this maybe?

#[allow(dead_code)]
#[derive(Debug, Default, Clone)]
pub struct ThingBuilder {
    foo: bool,
    bar: String,
    zot: Option<String>,
}

#[allow(dead_code)]
#[derive(Debug, Default, Clone)]
pub struct Thing {
    foo: bool,
    bar: String,
    zot: Option<String>,
}

impl ThingBuilder {
    #[must_use]
    pub fn new(foo: bool, bar: impl ToString) -> Self {
        Self {
            foo,
            bar: bar.to_string(),
            ..Default::default()
        }
    }

    pub fn with_zot(self, zot: Option<impl ToString>) -> Self {
        Self {
            zot: zot.map(|z| z.to_string()),
            ..self
        }
    }

  pub fn build(self) -> Thing {
      Thing { 
        foo: self.foo,
        bar: self.bar,
        zot: self.zot,
        
      }
  }
}

fn main() {
    let my_thing = ThingBuilder::new(true, "Hello world").with_zot(Some("testing")).build();
    eprintln!("{:?}", my_thing);
    // outputs `Thing { foo: true, bar: "Hello world", zot: Some("testing") }`

}

obviously it's easy to go "oh just like this" but that's what I mostly expect, there's also the unofficial rust pattern where the methods take a mut self: https://rust-unofficial.github.io/patterns/patterns/creational/builder.html

[lightsofapollo]

🤔 no I appreciate the feedback! This looks plausible to me I'll take a look when I come back to do the next iteration. Thank you for making the time to respond.