date-format

A rule that is off by default: it reports dates in more than one style in one text: 2026-10-13, Oct 2026, October 2026, 10/13/2026, or Sep beside Sept once a decisions table turns it on.

What it catches

Dates in more than one style in one text: 2026-10-13, Oct 2026, October 2026, 10/13/2026, or Sep beside Sept.

Dimension

conventions: a house or genre convention is broken. A finding is counted on the dimension of its rule, the cost it names to the reader.

Why

A reader compares dates by their form, and a mix makes each one a fresh parse; 10/13/2026 also reads two ways across locales. This repository's first decision record mixes May 2026 and Sept 2026 with 2026-09-19, where every later record writes ISO 8601 alone. May is both the full and the abbreviated name, so it takes no style; a date in code or quotes is not judged. The dates outside the text's most common style are reported. It is a convention, not a study, and no labeled firing yet, so it ships off and a decisions table turns it on.

Default decision

The code is PRF5007. The decision depends on the kind of text judged:

Changing it

A decisions table sets this rule to deny, advise or off, for everything judged or for the files a glob matches. Proofread reads the table from the file its -decisions flag names:

{
  "rules": {"date-format": "deny"},
  "paths": {"blog/**": {"date-format": "off"}}
}

rules applies to every file. A glob in paths applies to the files it matches, and the last match wins. A rule set to off never reports.

Seeing it

A finding names the rule, its code and the decision that applies, and links here:

{"rule": "date-format", "code": "PRF5007", "decision": "off", "url": "https://eli.gladman.cc/magus/reference/proofread/date-format/"}

proofread rules prints this entry with every other rule's.

See also

• All proofread rules - every rule, grouped by what it checks
• Writing rules - how the rules apply to this repository's pages and pull requests
• The findings contract - the fields every finding carries