Registers

The engine and each thread in the engine has a set of registers.

Engine Registers

Current Character	This is the current character from the input stream that is processed by the engine.
Next Character	This is the next character in the input stream.

Per-Thread Registers

Program Counter	A program counter pointing to the currently executed
Sequence Index	The sequence index is exclusively used by the Sequence operation.
Counter Array	A set of counters that are used by the Counter, Maximum and Minimum operations.
Capture Groups	A set of capture groups to mark the start and end of captured text.