ASN.1 Compiler

vest_asn1 parses an ASN.1 module and emits verified formats backed by vest_lib::asn1. DER is the default; BER and definition-level rule overrides are available.

cargo run -p vest_asn1 -- schema.asn1 -o generated.rs
cargo run -p vest_asn1 -- --rules ber schema.asn1 -o generated_ber.rs

Similar to the Vest DSL, each supported ASN.1 definition becomes a user-facing Rust value type and a nominal format type whose specification, proof, and executable implementation are all derived from the inner combinator representation.

Start with the ASN.1 tutorial, then see the generated Rust code and the support table. The backend API is documented under vest_lib::asn1.

DER, BER, and rule overrides

--rules der or --rules ber authoritatively selects the module default. A definition override changes that definition and the transitive children it needs under the selected rule; parents remain under the module default.

cargo run -p vest_asn1 -- --rules ber \
  --der-definition SignedAttributes \
  --der-definition CertificateSet \
  schema.asn1 -o generated_mixed.rs

Every ASN.1 definition is emitted exactly once with one global rule. A BER definition may contain a DER child because a DER encoding is valid BER. However, a DER definition cannot depend on a BER definition without violating DER canonicality. Conflicting transitive overrides are rejected and require an explicit rule boundary.