Examples

Quick start

use ftracker_identifiers::Cnpj;

let numeric = Cnpj::parse("00.000.000/0001-91").unwrap();
assert!(numeric.is_root());
assert_eq!(numeric.as_str(), "00000000000191");
assert_eq!(numeric.formatted().as_str(), "00.000.000/0001-91");

let alpha = Cnpj::parse("12ABC34501DE35").unwrap();
assert_eq!(alpha.branch_code(), "01DE");
assert_eq!(alpha.branch_number(), None);

Validating untrusted input

Use Cnpj::parse right at the boundary where data enters your system — an HTTP handler, a CSV import, a CLI argument — so that everything downstream can assume a Cnpj is already valid:

use ftracker_identifiers::Cnpj;

fn handle_signup(raw_cnpj: &str) -> Result<(), String> {
    let cnpj = Cnpj::parse(raw_cnpj).map_err(|e| e.to_string())?;
    // From here on, `cnpj` is guaranteed valid — no need to re-check it.
    save_company(cnpj);
    Ok(())
}
fn save_company(_: Cnpj) {}

Sorting and deduplicating a batch

A common data-cleaning task: importing a spreadsheet or CSV export that may contain the same CNPJ written multiple ways (with or without punctuation, mixed case), and needing a deduplicated, sorted list:

use ftracker_identifiers::Cnpj;

let mut cnpjs: Vec<Cnpj> = [
    "11.222.333/0002-62",
    "00.000.000/0001-91",
    "00000000000191", // same CNPJ as above, written without punctuation
]
.into_iter()
.map(|s| Cnpj::parse(s).unwrap())
.collect();

cnpjs.sort();
cnpjs.dedup();
assert_eq!(cnpjs.len(), 2);

Using `Cnpj` as a map or set key

Because Cnpj implements Eq and Hash consistently with PartialEq, it works directly as a HashMap/HashSet key (or BTreeMap/BTreeSet, via Ord) — useful for deduplicating records or indexing data by company:

use ftracker_identifiers::Cnpj;
use std::collections::HashMap;

let mut companies: HashMap<Cnpj, &str> = HashMap::new();
companies.insert(Cnpj::parse("00.000.000/0001-91").unwrap(), "Banco do Brasil");

let lookup = Cnpj::parse("00000000000191").unwrap();
assert_eq!(companies.get(&lookup), Some(&"Banco do Brasil"));

Grouping branches by root

Since Cnpj::root() identifies the entity regardless of branch, it’s a natural grouping key when you have several branch records for the same company:

use ftracker_identifiers::Cnpj;
use std::collections::HashMap;

fn group_by_company(cnpjs: &[Cnpj]) -> HashMap<&str, Vec<Cnpj>> {
    let mut groups: HashMap<&str, Vec<Cnpj>> = HashMap::new();
    for &cnpj in cnpjs {
        groups.entry(cnpj.root()).or_default().push(cnpj);
    }
    groups
}

For a config-file or API round-trip example using serde, see Feature Flags.

Keyboard shortcuts