Execution Result

paxman.canonicalize() always returns the same object shape — an ExecutionResult — whether the answer is a clean success, a missing input, an invalid value, or a genuine ambiguity. Learn to read it once, and you can handle every capability the same way.

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The shape

result.status  # Resolution enum
result.canonicalized_value  # str | None
result.candidates  # tuple[Candidate, ...]
result.span  # tuple[int, int] | None
result.version_stamp  # VersionStamp — which Paxman build produced this
result.contract  # the contract you passed in, echoed back

For each Candidate:

candidate.value  # canonical string this candidate proposes
candidate.recognition_rule  # grammar name that spotted it (e.g. "standard_recognition")
candidate.validation_rule  # rule name that validated it (e.g. "Section 3.4.1-addr-spec")
candidate.span  # (start, end) of this candidate's match in the input, or None
candidate.provenance  # tuple[Provenance, ...] — the spec(s) that vouched for it

version_stamp is currently VersionStamp(paxman_version="…"); it records the installed build so results are auditable. contract is echoed back for logging and debugging.

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The four statuses

Status	What it means	canonicalized_value	span	candidates
MISSING	Nothing in the input looked like this kind of entity	None	None	empty
INVALID	Looked like it, but no authority validated it	None	None	empty
SUCCESS	Exactly one canonical value, validated	str	(start, end) of that value	one or more agreeing candidates
AMBIGUOUS	One mention, two or more authorities that disagree	None	None	two+ disagreeing candidates

MISSING vs INVALID is not a wording choice — it is a pipeline signal (see Pipeline): MISSING means recognition found nothing; INVALID means recognition found something but validation rejected it. That tells you whether to try a different recognition flag or a different validation rule.

Python tip — always branch on status, not truthiness:

from paxman.core.domain import Resolution

if result.status == Resolution.SUCCESS:
    use(result.canonicalized_value)  # str
elif result.status == Resolution.MISSING:
    # input does not contain this entity — skip or report
    ...
elif result.status == Resolution.INVALID:
    # looks like the entity but malformed — flag for review
    ...
elif result.status == Resolution.AMBIGUOUS:
    # one mention, conflicting specs — narrow contract or ask user
    inspect(result.candidates)

canonicalized_value is None for every non-SUCCESS case by construction — check status, not whether the value is truthy.

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span — where the answer sat

span is a half-open [start, end) character range into the original text you passed to canonicalize(). It obeys len(raw_text) == end - start.

import paxman
from paxman.capabilities import Email

paxman.register_all_shipped()
contract = Email.create_contract()
result = paxman.canonicalize("Contact user@Example.com for info", contract)

print(result.canonicalized_value)  # "user@example.com"
print(result.span)  # (8, 24)
print("Contact user@Example.com for info"[8:24])  # "user@Example.com"

• On SUCCESS, result.span is the resolved span selected for the single canonical value — inspect each candidate.span when you need all evidence locations.
• On MISSING, INVALID, and AMBIGUOUS, result.span is None — there is no single resolved mention to point to. For AMBIGUOUS, locate each competing mention via candidate.span on the individual candidates.

This makes highlighting in UIs, logging, and downstream span-aware processing straightforward.

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candidates — the full evidence

candidates holds every validated (value, recognition_rule, validation_rule, provenance, span) tuple the pipeline produced, after deduplication by (value, recognition_rule, validation_rule).

• On SUCCESS with one agreeing value, candidates may still contain multiple entries that converged on that same string via different grammars or specs. That convergence is useful: it shows the answer is robust across rule/authorities.
• On AMBIGUOUS, candidates shows the disagreement — two or more distinct values with their respective specs.
• On MISSING / INVALID, candidates is empty.

for c in result.candidates:
    prov = c.provenance[0]
    print(
        f"{c.value!r:20} via {c.validation_rule}  "
        f"({prov.authority}: {prov.specification_name})  "
        f"span={c.span}"
    )

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Notebook-friendly pattern

import paxman
from paxman.capabilities import Country
from paxman.core.domain import Resolution

paxman.register_all_shipped()
contract = Country.create_contract(include_localized=True)

rows = ["United States", "Alemania", "not a country", "01/02/2026"]

for text in rows:
    # Use the capability that matches the column — example uses Country for the first three,
    # so "01/02/2026" will be MISSING here (it contains no country pattern).
    r = paxman.canonicalize(text, contract)
    tag = r.status.value
    val = r.canonicalized_value if r.status == Resolution.SUCCESS else "—"
    print(f"{text!r:20} {tag:10} {val!r:15} span={r.span}")

Check status first, use canonicalized_value only on SUCCESS, and fall back to candidates or span when you need to explain or highlight the outcome.

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In plain language

The execution result is like a lab report. It says what the verdict was (SUCCESS/MISSING/INVALID/AMBIGUOUS), what the cleaned-up value is if there is one, where in the original text it was found, and which rulebooks were consulted. You always get the same report format — only the verdict changes.

Next: Provenance → — who vouches for the answer and how to cite it.