Macro path 

macro_rules! path {
    ($($elem:expr),* $(,)?) => { ... };
}

Creates a path for use with LookupResult::decode_path().

This macro provides a convenient way to construct paths with mixed string keys and integer indexes.

Syntax

• String literals become PathElement::Key
• Non-negative integers become PathElement::Index
• Negative integers become PathElement::IndexFromEnd (e.g., -1 is the last element)

Examples

use maxminddb::{Reader, path};
use std::net::IpAddr;

let reader = Reader::open_readfile("test-data/test-data/GeoIP2-City-Test.mmdb").unwrap();
let ip: IpAddr = "89.160.20.128".parse().unwrap();
let result = reader.lookup(ip).unwrap();

// Navigate to country.iso_code
let iso_code: Option<String> = result.decode_path(&path!["country", "iso_code"]).unwrap();

// Navigate to subdivisions[0].names.en
let subdiv: Option<String> = result.decode_path(&path!["subdivisions", 0, "names", "en"]).unwrap();

use maxminddb::{Reader, path};
use std::net::IpAddr;

let reader = Reader::open_readfile("test-data/test-data/MaxMind-DB-test-decoder.mmdb").unwrap();
let ip: IpAddr = "::1.1.1.0".parse().unwrap();
let result = reader.lookup(ip).unwrap();

// Access the last element of an array
let last: Option<u32> = result.decode_path(&path!["array", -1]).unwrap();
assert_eq!(last, Some(3));

// Access the second-to-last element
let second_to_last: Option<u32> = result.decode_path(&path!["array", -2]).unwrap();
assert_eq!(second_to_last, Some(2));