Getting started with small-step operational semantics

This post introduces Small-Step Operational Semantics (SOS) as a formal method to specify and reason about the execution of sagas. It designs a mini-language, SagaLang, to illustrate SOS for basic sagas, sagas with retries (forward recovery), and sagas with compensations (backward recovery), highlighting the need for idempotence and compensation guarantees for true transaction-like behavior.