Group @testable imports at the bottom, per public/rules-swift's swiftformat. A
behavior-preserving import-ordering reformat across 252 files (mostly tests).
--trailingclosures was deliberately not adopted (cosmetic, and swiftformat flags
it as caution-worthy).
Slice 3 of #92. The DTD validator's imperative walk becomes declared Validation
values over a DTDSchema document:
- DTDSchema is now just the schema (content models + attribute declarations) and
serves as the rules' Document context; its validate/walk methods are gone.
- contentModel and attributeDeclarations are Validation<Element, DTDSchema>, so
every content-model and attribute violation is now located by coding path
("... at path: r/a"). undeclaredElement is added only in strict mode.
- identifierIntegrity is a Validation<Node, DTDSchema> gated to the root, doing
the document-wide ID-uniqueness and IDREF-resolution checks in one pass.
- DTD.validator(strict:) assembles the rule set; validateAgainstInternalDTD runs
it and returns [ValidationError] instead of [Issue].
A new test pins the located result. Schema (XSD) and Schematron validators still
use Issue and migrate in the following slices.
Surface the parsed <!DOCTYPE> internal subset's <!ELEMENT> declarations from the
parser and validate a tree against them. Reimplemented from the DTD content-model
spec; no upstream code copied.
- DoctypeScanner captures <!ELEMENT name model> declarations; the parser surfaces
them as Parsing.DocumentType (via parseWithDocumentType).
- Validation.ContentModel + ContentModelParser parse a model string (EMPTY, ANY,
(#PCDATA), mixed, and element content with sequence/choice and ?/*/+).
- ContentModelMatcher matches the child element-name sequence against a model as
a regular language (NFA-position matching).
- Validation.DTDSchema.validate reports issues for EMPTY/PCDATA/mixed violations,
element content with stray text, and child sequences that do not match.
- PureXML.validateAgainstInternalDTD(_:) parses and validates in one call.
- ATTLIST validation is out of scope. 9 tests; 70 total.
