IR Boundaries

The normalized IR describes schema semantics. It should not encode language-specific codegen choices.

Belongs in IR

• packages and included schema modules;
• enums, structs, unions, tables, fields, and indexes;
• table modes and keys;
• source metadata;
• field types, defaults, parsers, ranges, lengths, and comments;
• references and derived child-table field metadata;
• scopes.

Does Not Belong in IR

• Rust map implementation choices;
• TypeScript enum representation choices;
• Lua module names;
• runtime decoder dependency choices;
• formatter settings;
• target-specific file layout.

Those settings belong in [codegen.<target>] or in generator registration metadata.

Extension Boundary

schema input -> normalized IR -> validation
                              |-> exporter registry
                              |-> codegen registry

A new language generator should consume the IR and its own target options. A new runtime data format should be added as an exporter. Neither should require changing the schema model unless the actual data semantics need to change.