feat(swift_core): implement SchemaCompiler for AST translation

[pinieb]

Description

• Fully implement SchemaCompiler to translate JSONValue into SchemaNodes.
• Add support for boolean schemas (true = always valid, false = always invalid).
• Implement structural keyword interception ($id, $defs, $dynamicAnchor).
• Ensure $id properly updates the base URI and resets the JSON pointer scope.
• Ensure $defs are recursively compiled and cached in the SchemaRegistry
  for synchronous $ref lookup during evaluation.
• Add comprehensive compiler test coverage for scope resets and definition caching.

Pre-launch Checklist

For this PR:

• I have added updates to the CHANGELOG.
• I updated/added relevant documentation.
• My code changes (if any) have tests.
• If my branch is on fork, I have verified that scripts/e2e_test.sh passes.
  • Ran run_tests.sh for Swift

If you need help, consider asking for advice on the discussion board.

[gemini-code-assist]

Code Review

This pull request introduces the A2UISwiftCore package, establishing a generic JSON Schema Draft 2020-12 validator and DSL builder target (JSONSchema) in Swift, complete with unit tests, documentation, and formatting scripts. The review feedback highlights critical improvements needed for full schema specification compliance: SchemaIdentity should support plain string anchors in URI fragments rather than assuming they are always JSONPointers, and compiled schemas must be registered under their anchor-based URIs in the SchemaRegistry to prevent reference resolution failures. Additionally, updatingBaseURI should be updated to correctly handle and split fragments in the new URI to avoid malformed URIs.

[gemini-code-assist]

The SchemaIdentity initializer currently assumes that any URI fragment is a valid JSONPointer. If the fragment is a plain anchor (e.g., #my-anchor), JSONPointer(stringRepresentation:) will return nil, causing the entire SchemaIdentity initialization to fail.\n\nIn JSON Schema Draft 2020-12, plain anchors are valid URI fragments used by $anchor and $dynamicAnchor. To support resolving schemas via anchors, SchemaIdentity should be updated to allow fragments that are either a JSONPointer or a plain string anchor.

[gemini-code-assist]

While $dynamicAnchor is parsed here, the compiled SchemaNode is not registered in the SchemaRegistry under its anchor-based URI (e.g., baseURI + \"#\" + anchorStr). Additionally, interception and registration for the standard $anchor keyword are completely missing.\n\nThis is likely a consequence of SchemaIdentity only supporting JSONPointer fragments. Without registering schemas under their anchor URIs, resolving references ($ref or $dynamicRef) that point to anchors (e.g., \"$ref\": \"#my-anchor\") will fail during evaluation.

[gemini-code-assist]

If newURI contains a fragment, SchemaIdentity(uncheckedBaseURI:pointer:) will not split it, leaving the fragment inside baseURI. This can lead to malformed URIs when subsequent paths are appended (e.g., https://example.com/schema#foo#/properties/bar).\n\nWe can resolve this by attempting to parse newURI using SchemaIdentity(uri:) first, which correctly splits the fragment if present.

  public func updatingBaseURI(to newURI: String) -> SchemaIdentity {
    if let parsed = SchemaIdentity(uri: newURI) {
      return parsed
    }
    return SchemaIdentity(uncheckedBaseURI: newURI, pointer: JSONPointer())
  }