Comprehensive Rust 🦀

Serializer: Property を実装する

// Copyright 2025 Google LLC
// SPDX-License-Identifier: Apache-2.0

use std::fmt::Write as _;
struct Serializer<S> {
    // [...]
    indent: usize,
    buffer: String,
    state: S,
}

struct Struct<S>(S);
struct Property<S>(S);
struct List<S>(S);

impl<S> Serializer<Property<Struct<S>>> {
    fn serialize_struct(mut self, name: &str) -> Serializer<Struct<Struct<S>>> {
        // [...]
        writeln!(self.buffer, "{name} {{").unwrap();
        Serializer {
            indent: self.indent + 1,
            buffer: self.buffer,
            state: Struct(self.state.0),
        }
    }

    fn serialize_list(mut self) -> Serializer<List<Struct<S>>> {
        // [...]
        writeln!(self.buffer, "[").unwrap();
        Serializer {
            indent: self.indent + 1,
            buffer: self.buffer,
            state: List(self.state.0),
        }
    }

    fn serialize_string(mut self, value: &str) -> Serializer<Struct<S>> {
        // [...]
        writeln!(self.buffer, "{value},").unwrap();
        Serializer { indent: self.indent, buffer: self.buffer, state: self.state.0 }
    }
}

Property 状態のメソッドが追加されたことで、図はほぼ完成です: