toml-rs

Minimal TOML 1.0.0 parser — zero dependencies, pure Rust stdlib only.

Part of the nativelite ecosystem: every crate is auditable in an afternoon, with no third-party dependencies in the critical path.

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Features

• Zero dependencies — only std, no serde, no external crates.
• TOML 1.0.0 compliant for common structures.
• Strings: basic ("…"), multi-line ("""…"""), literal ('…'), multi-line literal ('''…''').
• Numbers: integers (with _ separators), floats (including exponential notation).
• Booleans: true / false.
• Datetimes: RFC 3339 / ISO 8601 stored as strings.
• Arrays: homogeneous and heterogeneous.
• Tables: regular [section], dotted keys a.b.c = v, inline { k = v }.
• Comments: # to end of line.
• Error messages include line and column numbers.

Out of scope (v1)

• Array of tables [[…]]
• Date arithmetic

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API

use toml_rs::{parse, TomlValue, ParseError};

// Parse a TOML document.
let value: TomlValue = parse(input)?;

// TomlValue variants
match value {
    TomlValue::String(s)   => { /* &str */ }
    TomlValue::Integer(n)  => { /* i64 */ }
    TomlValue::Float(f)    => { /* f64 */ }
    TomlValue::Boolean(b)  => { /* bool */ }
    TomlValue::DateTime(d) => { /* raw RFC 3339 string */ }
    TomlValue::Array(v)    => { /* Vec<TomlValue> */ }
    TomlValue::Table(m)    => { /* HashMap<String, TomlValue> */ }
}

// ParseError carries position info.
if let Err(e) = parse(bad_input) {
    println!("Error at line {}, col {}: {}", e.position.line, e.position.column, e.message);
}

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Usage example

use toml_rs::{parse, TomlValue};

let config = r#"
[agent]
name    = "search-agent"
version = 2
enabled = true
model   = "claude-3-opus"

[agent.limits]
max_tokens = 4096
timeout_ms = 30000
"#;

let doc = parse(config).unwrap();
if let TomlValue::Table(root) = &doc {
    if let Some(TomlValue::Table(agent)) = root.get("agent") {
        println!("Agent: {:?}", agent["name"]);
    }
}

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Running tests

cargo test

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License

MIT