Function write_frontmatter_field

atomic-repository/src/repository/vault.rs:1025–1069

Write a single frontmatter field in YAML format.

(output: &mut String, key: &str, value: &serde_json::Value)

/// Write a single frontmatter field in YAML format.
fn write_frontmatter_field(output: &mut String, key: &str, value: &serde_json::Value) {
    use std::fmt::Write;
    match value {
        serde_json::Value::String(s) => {
            // Keep simple strings readable, but quote values that our parser
            // would otherwise reinterpret as another scalar/container type.
            // JSON string syntax is valid YAML and preserves escapes.
            let parsed_unquoted = parse_yaml_value(s);
            let has_edge_whitespace = s.chars().next().is_some_and(char::is_whitespace)
                || s.chars().last().is_some_and(char::is_whitespace);
            if parsed_unquoted != serde_json::Value::String(s.clone())
                || s.contains(": ")
                || s.contains('#')
                || s.contains('\n')
                || s.starts_with('{')
                || s.starts_with('[')
                || s.starts_with('"')
                || s.starts_with('\'')
                || has_edge_whitespace
            {
                let rendered = serde_json::to_string(s).unwrap_or_else(|_| "\"\"".to_string());
                let _ = writeln!(output, "{}: {}", key, rendered);
            } else {
                let _ = writeln!(output, "{}: {}", key, s);
            }
        }
        serde_json::Value::Number(n) => {
            let _ = writeln!(output, "{}: {}", key, n);
        }
        serde_json::Value::Bool(b) => {
            let _ = writeln!(output, "{}: {}", key, b);
        }
        serde_json::Value::Array(arr) => {
            let rendered = serde_json::to_string(arr).unwrap_or_else(|_| "[]".to_string());
            let _ = writeln!(output, "{}: {}", key, rendered);
        }
        serde_json::Value::Object(_) => {
            // Inline JSON for nested objects
            let _ = writeln!(output, "{}: {}", key, value);
        }
        serde_json::Value::Null => {
            let _ = writeln!(output, "{}: null", key);
        }
    }
}

// ── Deflation helpers ───────────────────────────────────────────────────