canton-daml-stdlib

Pre-built typed Rust bindings for the Daml standard library — daml-stdlib, daml-prim, ghc-stdlib and their per-module packages.

Part of the Canton Rust SDK.

Why this crate exists

Every DAR carries the standard library in its dependency closure. Generating a DAR whole therefore gives each generated crate its own RelTime, Set, NonEmpty and so on — and Rust treats those copies as unrelated types. A RelTime read through one bindings crate then does not typecheck against the RelTime of another, though both name the same Daml type in the same package:

error[E0308]: mismatched types
note: `RelTime` is defined in crate `canton_splice_api_token_metadata_v1`
note: `RelTime` is defined in crate `canton_splice_api_token_holding_v1`

This crate owns those packages so that every other crate can reference them. One RelTime, whichever crate you reach it through.

Generated, not written

src/lib.rs is checked-in generated output. Do not edit it by hand; a drift guard in canton-codegen regenerates it and fails if it no longer matches.

The standard library ships no DAR of its own, so this crate is generated from a selection of packages taken out of a DAR that carries them — the one committed to this repository, which means this crate's drift guard needs no external checkout and runs in CI with the rest.

Versioning

The package ids here are those of the Daml SDK the corpus DARs were built with. A DAR built against a different SDK carries a standard library with different package ids, which is a genuinely different set of Daml packages — not a mismatch to paper over. Bindings for such a DAR keep their own copy unless a crate exists for that version too.

Licence

Apache-2.0. See LICENSE.