openbim-step

Pure-Rust, schema-independent infrastructure for ISO 10303.

Implemented scope

• ISO 10303-21 tokens with source spans and diagnostics;
• STEP string escaping, including legacy \P alphabet selection for \S escapes;
• generic HEADER records, one DATA section, arbitrary-precision instance IDs, simple and complex records, user-defined keywords, and parameters;
• a compact owned model: short strings inline, long names shared per parse, simple instances without a record list, parameter lists as boxed slices;
• arbitrary-precision integer/real lexemes, validated binary syntax, and deterministic syntax-safe writing;
• owning parser, record partitioning, and incrementally emitted event/sink parsing;
• a lazy record index (scan) that frames every data record without decoding it, and decode_record to parse one record on demand;
• structural EXPRESS declaration parsing and generic AST.

The current Part 21 model covers the classic exchange structure used by IFC. Edition 3 anchor/reference sections and multiple DATA sections are not yet represented. The EXPRESS frontend is intentionally incomplete: complete functions, procedures, rules, WHERE/UNIQUE semantics, and executable schema validation remain future work. IFC-specific graph mapping and policy live in openbimrs/ifc.

bash scripts/gate.sh

AGPL-3.0-or-later licensed.