RFC 3028 Sieve: A Mail Filtering Language January 2001 2.6. Arguments ............................................. 9 2.6.1. Positional Arguments .................................. 9 2.6.2. Tagged Arguments ...................................... 10 2.6.3. Optional Arguments .................................... 10 2.6.4. Types of Arguments .................................... 10 2.7. String Comparison ..................................... 11 2.7.1. Match Type ............................................ 11 2.7.2. Comparisons Across Character Sets ..................... 12 2.7.3. Comparators ........................................... 12 2.7.4. Comparisons Against Addresses ......................... 13 2.8. Blocks ................................................ 14 2.9. Commands .............................................. 14 2.10. Evaluation ............................................ 15 2.10.1. Action Interaction .................................... 15 2.10.2. Implicit Keep ......................................... 15 2.10.3. Message Uniqueness in a Mailbox ....................... 15 2.10.4. Limits on Numbers of Actions .......................... 16 2.10.5. Extensions and Optional Features ...................... 16 2.10.6. Errors ................................................ 17 2.10.7. Limits on Execution ................................... 17 3. Control Commands ....................................... 17 3.1. Control Structure If .................................. 18 3.2. Control Structure Require ............................. 19 3.3. Control Structure Stop ................................ 19 4. Action Commands ........................................ 19 4.1. Action reject ......................................... 20 4.2. Action fileinto ....................................... 20 4.3. Action redirect ....................................... 21 4.4. Action keep ........................................... 21 4.5. Action discard ........................................ 22 5. Test Commands .......................................... 22 5.1. Test address .......................................... 23 5.2. Test allof ............................................ 23 5.3. Test anyof ............................................ 24 5.4. Test envelope ......................................... 24 5.5. Test exists ........................................... 25 5.6. Test false ............................................ 25 5.7. Test header ........................................... 25 5.8. Test not .............................................. 26 5.9. Test size ............................................. 26 5.10. Test true ............................................. 26 6. Extensibility .......................................... 26 6.1. Capability String ..................................... 27 6.2. IANA Considerations ................................... 28 6.2.1. Template for Capability Registrations ................. 28 6.2.2. Initial Capability Registrations ...................... 28 6.3. Capability Transport .................................. 29 7. Transmission ........................................... 29 Showalter Standards Track