compact-core:compact-structure

Compact contract structure requires pragma declarations, CompactStandardLibrary imports, custom types, ledger and witness declarations, a constructor, helper circuits, and exported transaction circuits in a specific order to compile correctly for ZK proving.

Disclosure rules in Compact contracts determine what data is revealed versus kept private during ZK-proof generation. They govern how ledger states and witness data interact with off-chain provers and on-chain verification.

Sealed ledgers and witnesses in Compact are declared after imports and custom types. Sealed ledgers protect state privacy, while witness declarations define the zero-knowledge proof inputs needed for circuit execution and validation.

Common Compact compile-time mistakes include incorrect type casting, missing language-version pragmas, improper ADT references, and violating pure circuit constraints. Following proper contract anatomy and disclosure rules prevents these errors.

Yes, Midnight Compact supports Merkle membership and commit-reveal patterns within circuits. These patterns use custom types, maps, and witness declarations to enable private authentication and zero-knowledge verification.

Pure circuits in Compact contracts are needed when circuits must meet ZK-proof constraints without modifying ledger state. They isolate computational logic for off-chain provers while maintaining disclosure rules and type safety.