Crate ears_classifier 

EARS requirement classification and the ISO/IEC 25010 quality vocabulary (FEAT-049).

EARS (Easy Approach to Requirements Syntax) gives a requirement a shape that can be tested: one behaviour, one trigger, no compound sentences. This module classifies text — it never rejects it. Stored requirements keep whatever the author wrote; doctor reports what doesn’t conform. That is deliberate: a write that fails because of prose style would push people to stop recording requirements at all, and the pattern is derived on demand so stored data can never disagree with the classifier.

What is deliberately NOT checked: compound responses (“SHALL validate and reject”). A regex for that fires on legitimate single behaviours, and a check people learn to ignore is worse than no check.

Enums

Pattern

The five EARS patterns.

Constants

ISO25010

The nine ISO/IEC 25010 (2023) quality characteristics.

Functions

classify

Classify a requirement. None means it does not conform — a warning, never an error.

normalize_iso

Canonical spelling of a quality tag, ignoring case, spacing and hyphens. None for a tag outside the standard — reported, never rejected, because a hard failure here would break a board load over a typo.