Nested structures in Rust

Structs inside vectors inside structs — serde follows the whole tree.

use serde::{Deserialize, Serialize};

#[derive(Debug, Serialize, Deserialize)]
struct Tour {
    slug: String,
    sections: Vec<Section>,
}

#[derive(Debug, Serialize, Deserialize)]
struct Section {
    title: String,
    steps: Vec<String>,
}

fn main() -> Result<(), serde_json::Error> {
    let tour = Tour {
        slug: "traits".to_string(),
        sections: vec![Section {
            title: "Trait objects".to_string(),
            steps: vec!["rs_trait_objects.rs".to_string()],
        }],
    };
    println!("{}", serde_json::to_string_pretty(&tour)?);
    Ok(())
}

How it works

Any field whose type derives the traits just works.
Vec<T> becomes a JSON array of objects.
to_string_pretty is the readable form.

Keywords and builtins used here

Ok
Result
Section
String
Tour
Vec
fn
let
main
struct
use
vec

The run, in numbers

Lines: 25
Characters to type: 499
Tokens: 134
Three-star pace: 105 tpm

At the three-star pace of 105 tokens a minute, this run takes about 77 seconds.

Type this snippet

Step 1 of 2 in Shapes, step 7 of 11 in Serde & JSON.

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