State Machine Pattern
Model system behavior as discrete states with defined transitions. Current state determines which actions are valid and what state comes next.
ikigai Application
Input parser: Tracks escape sequence state (normal, escape, CSI, etc.) to interpret terminal input bytes.
Streaming response: States like idle → requesting → streaming → complete → idle.
Implementation: Enum for states, switch or function pointer table for transitions:
typedef enum { STATE_IDLE, STATE_STREAMING, STATE_ERROR } stream_state_t;
REPL states: Input mode, scrolling mode, command mode.
Benefit: Complex input handling becomes manageable. Each state handles its valid inputs.