IPLDSchema class

IPLD schema validator for structured data validation.

Validates IPLD nodes against type schemas including structs, maps, lists, enums, unions, links, and scalar kinds. Supports the commonly-used subset of the IPLD schema DSL (https://ipld.io/specs/schemas/):

• type declarations addressed by name.
• Kinds: struct, map, list, enum, union, link, bytes, string, int, float, bool, null, any, unit, copy.
• Field modifiers optional and nullable on struct fields, and valueNullable on map/list value types.
• Representation strategies: map, listpairs, stringpairs, tuple, stringjoin (structs and maps); kinded, keyed, envelope/ enveloped, inline, stringprefix, bytesprefix/byteprefix (unions); string, int (enums); advanced (see below).
• Link types may carry expectedType (e.g. {"kind": "link", "expectedType": "Foo"}). When an IPLDLinkResolver is supplied — per call or via the constructor — the link target is loaded and validated against that type, with failures reported at the link's path. Without a resolver links are kind-checked only.
• advanced representations name an ADL whose data-model shape is declared in the schema's top-level advanced map ({<adl>: <term>}) or the adlTypes registry. The ADL name is taken from representation: {advanced: <name>}, or defaults to the type's own name per the IPLD spec. A representation clause that explicitly references an undeclared ADL name throws IPLDSchemaError when the schema is constructed; ADLs that are merely unknown (no declared or registered schema) skip validation leniently.
• Legacy extensions are preserved: valueConstraint (min, max, pattern, minLength, maxLength), required/optional field lists, strict unknown-key rejection, and {"kind": "type", "valueType": ...} reference wrappers.

Two validation styles are available: validate returns a boolean for backward compatibility, while check returns a SchemaValidationResult carrying every error with a precise path. validateOrThrow throws IPLDSchemaError with the first offending path. The synchronous check/validateOrThrow entry points never resolve links; use checkAsync/validateOrThrowAsync (or validate with a resolver) to enforce link expectedType clauses.