Capabilities

A capability is one kind of identifier Paxman knows how to canonicalize. Each capability is a self-contained package — its own patterns, its own specifications, its own rendering — that plugs into the shared pipeline.

You pick a capability by picking a contract (see Contracts). The two are paired: Email.create_contract() selects the Email capability, Country.create_contract() selects Country, and so on.

---

How selection works

1. Each capability has a lowercase name (e.g. "email", "country", "url").
2. Its contract carries that name in capability_name.
3. paxman.canonicalize(text, contract) looks up the capability by that name in the registry.
4. Only that capability’s grammars and rules run for the call — other capabilities’ grammars never see the input. (With register_all_shipped() every shipped capability is loaded; with register_capability(Email()) only Email is.)

This keeps imports cheap: from paxman.capabilities import Email loads only Email, not every capability.

---

What a capability contains

• Notation — internal shape (not part of the public API).
• Grammars — recognizers that scan your text and emit span-bearing matches. Pure syntax — no spec judgment.
• Rules — validators that check each match against an authoritative spec (RFC, ISO standard, etc.) and produce a canonical value plus provenance.
• Contract — the user-facing configuration (see Contracts).
• format_value — the sole rendering step, controlled by output_format on the contract.

You never interact with notations, grammars, or rules directly — you configure them through the contract and read their outcome in the result.

---

Capabilities available today

The set below reflects the current release and is intentionally not presented as a final count. New capabilities are added in minor releases — always check paxman.capabilities or the release notes for the latest list.

Capability	What it canonicalizes	Key formats it recognizes	Canonical form you get back
Country	Country codes and names	alpha-2, alpha-3, numeric, names; optional localized (CLDR) and historical names	alpha-2 code ("US"), or other form via output_format
Currency	Currency identifiers (no amounts)	ISO 4217 alpha-3 codes, CLDR symbols and display names	uppercase alpha-3 code ("USD")
Date	Calendar dates	ISO 8601, slash-ISO, US, European	ISO YYYY-MM-DD by default
Email	Email addresses	standard, obfuscated (user at domain dot com), localhost	lowercased addr-spec
IP	IP addresses	IPv4, IPv6 (optionally disabled)	normalized address (IPv6 per RFC 5952)
ISBN	ISBN identifiers	ISBN-13 and ISBN-10 (legacy → ISBN-13)	bare 13-digit form or hyphenated
Money	Money amounts with currency	codes, symbols, or names adjacent to an amount	CODE amount padded to minor units
Phone	Phone numbers	E.164, tel-URI, 00-prefix international, NANP national	E.164 (+15551234567) or other via output_format
SI Unit	SI unit expressions	symbols, names, product/quotient compounds	canonical symbol form ("kg", "m/s2")
URL	Absolute URIs / IRIs	absolute URIs (WHATWG URL Standard)	WHATWG serialization (lowercased host, etc.)
BIC	Business identifier codes (ISO 9362)	8/11-character codes	bic form
Coordinates	WGS 84 coordinates	decimal pairs, DMS, Geo URI, ISO 6709, GeoJSON	lat-first signed decimal degrees
ChemicalElement	Chemical elements (IUPAC)	symbols, names, labeled atomic numbers	proper-case symbol ("Fe")
IBAN	Bank account numbers (ISO 13616)	electronic compact, paper groups-of-four, labels	compact electronic form
ISSN	Serial identifiers (ISO 3297)	hyphenated, compact, labels	hyphenated ("0317-8471")
Language	Language identifiers (BCP 47)	tags, codes, names	bcp47 tag
MacAddress	MAC addresses (IEEE 802)	colon/hyphen/dot groups	colon form
ORCID	Researcher identifiers (ISO 27729)	hyphenated, compact, URIs	hyphenated orcid form
Timezone	Time zone identifiers (IANA TZDB 2026d)	zone keys, legacy Links, fixed zones, SystemV names	IANA key ("America/New_York"); opted-in SystemV names keep their fixed-rule key ("EST5EDT")
UtcOffset	UTC offset values (ISO 8601-1)	prefixed/bare offsets, Z	extended +HH:MM ("+05:30")
UUID	UUIDs (IETF RFC 9562)	hyphenated, bare hex, braced, URN carriers	lowercase hyphenated ("6ba7b810-9dad-11d1-80b4-00c04fd430c8")
DOI	Digital object identifiers (ISO 26324)	bare names, resolver URLs, doi: labels, urn:doi:/info:doi/ carriers	bare lowercase 10. name ("10.1038/nature12345")
ISIN	Securities identification numbers (ISO 6166)	compact 12-char codes, single-space groupings, ISIN labels	compact uppercase ("US0378331005")
ISNI	Public-identity identifiers (ISO 27729)	spaced quads, compact, hyphenated, ISNI labels, isni.org URIs, urn:isni: carriers	spaced display ("0000 0001 2103 2683")
LEI	Legal entity identifiers (ISO 17442)	compact 20-char codes, single-space forms, LEI labels, urn:lei: carriers	compact uppercase ("5493000IBP32UQZ0KL24")
GTIN	Trade item identifiers (GS1)	compact 8/12/13/14 runs, zero-padded 14-digit fields, space/hyphen groupings, GTIN/UPC/EAN labels, (01)/AI 01 markers	14-digit zero-padded ("00614141999996"); native offers the spelled length
CreditCard	Payment card numbers (ISO/IEC 7812-1)	compact 12–19-digit runs, space/hyphen groupings (4-4-4-4, 4-6-5, 14-digit), PAN labels	contiguous digits ("4111111111111111"); grouped offers groups-of-four
Domain	Hostnames (RFC 1034/1035, UTS #46, RFC 5893, IANA Root Zone)	bare FQDNs any case, root dots, U-labels, ACE labels, fullwidth/dot variants, embedded mentions	lowercase A-label ("xn--mnchen-3ya.de"); unicode offers the U-label rendering
UNSPSC	Product/service codes (UNDP UNSPSC)	bare 8-digit, zero-padded parents, 6-digit aliases, UNSPSC labels, UNSPSC000. MDM IDs, 10-digit +BFI	8-digit wire stem ("44103103"); labeled/native offered
MinorPlanet	Minor-planet designations (MPC)	unpacked provisionals, packed 7-char, extended _, surveys both spellings, parenthesized and packed numbers	unpacked canonical ("1995 XA"); packed offered

This table is an overview. Each capability’s contract documents its specific flags (e.g. include_localized for Country, default_country for Phone). See Contracts and the README examples for per-capability details; each row is expanded into its own guide under Capabilities.

---

Registering capabilities

Before the first canonicalize() call, register:

import paxman
from paxman.capabilities import Email, Country

# Option A — everything shipped in this release
paxman.register_all_shipped()

# Option B — explicit, dependency-clear
paxman.register_capability(Email())
paxman.register_capability(Country())

• Registration must complete from a single thread before the first call.
• After the first call the registry freezes — further register_* calls raise CapabilityError. Reads from any thread are then safe.

---

In plain language

Think of a capability like a department that handles one kind of paperwork. The Country department knows passports and country codes; the Email department knows addresses. You hand your paper to the right department by handing it a contract stamped with that department’s name. Only that department looks at it. Other departments never see it.

Next: Contracts → — how to configure what the chosen capability does.