Implements a three-phase Sieve email filtering pipeline:
- Data models (SieveCondition, SieveAction, SieveRule) as sealed Dart classes
- SieveParser: converts RFC 5228 Sieve scripts to a flat SieveRule list,
supporting if/elsif/else, allof/anyof, header/size/exists tests, and all
common actions (fileinto, keep, discard, flag, mark)
- SieveInterpreter: evaluates compiled rules against a SieveEmailContext,
tracking routing state in SieveExecutionContext with implicit keep behaviour
- 40 unit tests covering parser correctness and interpreter execution
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Thomas Güttler