| name | ketraterm-parser-fsm |
| description | Parser FSM and protocol dispatch guidance for this terminal emulator. Use when touching ByteClass, AnsiStateMachine, ActionEngine, ParserState, CSI/ESC/OSC/DCS handling, SGR dispatch, charset mapping, UTF-8 recovery, or TerminalParser full byte-stream behavior. |
Terminal Parser FSM
Use this skill when changing parser state machines, action engines, protocol
dispatch, or byte-stream recovery behavior.
Boundaries
- Parser owns UTF-8 decoding, ANSI state transitions, string termination,
parameter assembly, charset shifts, grapheme segmentation, and semantic sink
calls.
- Parser does not own terminal width, grid bounds, cursor clamping, cell width,
scrollback, rendering, or durable core state.
FSM Rules
- Keep byte classification, matrix transitions, actions, and command dispatch
separate.
- CSI dispatch should use structural signatures, not final-byte-only switches.
- String states need string-local control handling; do not use global execute
semantics inside OSC/DCS/SOS/PM/APC bodies when real terminal rules differ.
- Bound OSC/DCS payloads. Ignore overflow-sensitive semantic commands unless a
clear policy allows dispatch.
- Unknown or malformed sequences must recover according to terminal semantics,
not accidentally print or dispatch as another command.
Test Checklist
Add tests at the narrowest useful level and full parser level when observable:
- byte class and state table coverage.
- CAN/SUB aborts.
- ESC
\ ST termination from string states.
- BEL OSC termination.
- omitted, empty, colon, and overflowing params.
- max params, intermediates, payloads, and cluster length.
- malformed UTF-8 followed by ASCII, ESC, CSI, and string terminators.
- chunk boundaries around every structural byte.
Tests must assert real terminal semantics, not current implementation quirks.
