TOML (std::toml)

Root-level scalars and a [server] section as a sub-map.

// Feature: toml.parse — converts a TOML string into a map
// When to use: read configurations (Cargo.toml, pyproject.toml etc.).
// Note: for inline TOML, plain strings work — TOML does not use `{`/`}`
// at the top level, so there is no clash with interpolation.

use std::toml

let raw = "name = \"zolo\"\nversion = \"0.1.0\"\ndebug = true"
let cfg = toml.parse(raw)

print(cfg["name"])  // expected: zolo
print(cfg["version"])  // expected: 0.1.0
print(cfg["debug"])  // expected: true

// Sections become sub-maps.
let raw2 = "[server]\nhost = \"localhost\"\nport = 8080"
let cfg2 = toml.parse(raw2)
print(cfg2["server"]["host"])  // expected: localhost
print(cfg2["server"]["port"])  // expected: 8080

Serialisation and round-trip verification.

// Feature: toml.stringify — serializes a map into a TOML string
// When to use: generate a configuration file programmatically.

use std::toml

let cfg = #{
  name: "zolo",
  version: "0.1.0",
  debug: false,
}

let out = toml.stringify(cfg)
print(out)

// expected (key order may vary):
// name = "zolo"
// version = "0.1.0"
// debug = false

// Round-trip: parse(stringify(x)) == x for scalar values.
let back = toml.parse(out)
print(back["name"])  // expected: zolo
print(back["debug"])  // expected: false

String, int, float, bool and array in the same TOML document.

// Feature: toml — supported types (string, int, float, bool, array)
// When to use: TOML expresses primitive types unambiguously — useful to
// distinguish strings from numbers, unlike YAML/JSON.

use std::toml

let raw = "name = \"app\"\ncount = 42\nrate = 3.14\nactive = true\ntags = [\"a\", \"b\", \"c\"]"
let cfg = toml.parse(raw)

print(cfg["name"])  // expected: app
print(cfg["count"])  // expected: 42
print(cfg["rate"])  // expected: 3.14
print(cfg["active"])  // expected: true
print(cfg["tags"][0])  // expected: a
print(cfg["tags"][2])  // expected: c