//! # Engine Layer
//!
//! The engine processes the linear sequence of ZPL commands into a set of
//! self-contained, renderable instructions. It manages the state machine
//! that tracks label configurations like origin, font settings, and barcode
//! defaults.
//!
//! ## Core Workflow
//! 1. Receives a stream of `Command` enums from the AST parser.
//! 2. Updates the internal state as modal commands are processed.
//! 3. Emits a `ZplInstruction` when a field separator (`^FS`) is encountered.
//! 4. Produces a final `Vec<ZplInstruction>` ready for the rendering backends.
pub use ZplForgeBackend;
pub use ;
pub use ZplEngine;
pub use FontManager;