openbim-step

openbim-step is the reusable, IFC-independent Rust substrate for ISO 10303 STEP syntax.

Implemented capabilities:

• ISO 10303-21 lexical tokens, spans, diagnostics, parsing, deterministic writing, record-aligned partitioning, and streaming event/sink parsing;
• schema-independent HEADER and single-DATA exchange models with simple and complex instances;
• lossless lexical storage for unbounded instance identifiers and numeric values;
• classic and Unicode STEP string forms, including alphabet-selection directives and edition-3 direct UTF-8;
• structural, explicitly partial ISO 10303-11 EXPRESS parsing and AST types.

IFC graph conversion, schema lowering, validation, migration, and domain policy deliberately live in the downstream openbimrs/ifc family.

See the repository README for scope, examples, and support boundaries.