C2PO Parse Tree

C2PO Parse Tree#

The C2PO Parse Tree (CPT), defined in c2po/cpt.py, is the core IR used across parsing, type checking, transforms, optimization, SMT encoding, and assembly.

Core Structures#

  • Program: section-level container (INPUT, STRUCT, ENUM, DEFINE, FTSPEC, PTSPEC) and FT/PT spec sets.

  • Context: mutable compiler state (definitions, symbols, signal mapping, atomics, constraints for .equiv, generated assembly/binary, stats, and tool paths).

  • Expression graph: formulas/operators/signals/constants used by all passes and emitters.

Traversals and Rewrites#

Most command implementations walk expressions with traversal helpers:

  • postorder(...) for bottom-up analyses/transforms

  • preorder(...) for top-down transforms/inspection

These traversals are context-aware (for example, bound-variable handling in set aggregation).

SCQ Sizing#

SCQ sizes are computed from expression structure and propagation-delay properties, then attached to nodes before assembly (compute_scq_sizes).

The resulting queue sizes drive temporal memory allocation in generated configuration instructions.

Engine Assignment and Atomics#

CPT expressions are assigned to either:

  • Booleanizer engine (BZ), or

  • Temporal Logic engine (TL)

Any BZ expression consumed by TL is treated as an atomic interface value. These interfaces are identified by compute_atomics and later emitted as coordinated BZ/TL instructions during assembly.