Add PureXML.Parsing.ByteEncoder, the inverse of ByteDecoder, and a
Serializer.serialize(_:encoding:) / PureXML.serialize(_:encoding:) that
emits bytes in a chosen encoding (the libxml2 save-with-encoding model).
Covers the Unicode transformation formats and the single-byte legacy
families, built by inverting the existing vendored to-Unicode tables, so
no new data is introduced. The declaration carries the canonical encoding
name, a UTF-16/32 stream is preceded by a byte-order mark, and any
unrepresentable scalar becomes a decimal numeric character reference, so
output round-trips. CJK output encodings remain (tracked on #106).
Part of #106, #105
The error-array forms of && and || were unit-tested; the Bool predicate
forms were not. Add a pure-function test so every combinator overload in
the algebra is exercised, completing the framework's combinator coverage.
The identity-constraint location walk handles arbitrary selector depth, but
the existing assertions only exercised a single relative step. Add a nested
selector (group/item) whose duplicate sits in the second group, so the
offender is a grandchild and an intermediate level needs a sibling index:
list/group[2]/item. Locks the multi-level path construction.
Refine the identity-constraint path: rather than locating at the element
that declares the key, walk from the constraint-bearing element down to the
selected target and report the actual offender, so a duplicate key renders
"at path: list/item[2]" and a dangling keyref "at path: orders/line".
Also locate the "no element declaration for the root" XSD error at the root
element, matching the namespace check beside it that already did so. Lock
both with coding-path assertions in the identity tests.
The IdentityValidator emitted every key/keyref/unique error with an empty
coding path (at: []), so each rendered "at root of document" regardless of
which element violated the constraint. Thread a [PathKey] through the walk,
the way the content-model validator already does, so the failures carry the
constraining element's path. This restores the validation framework's
path-carrying contract for the one rule that was bypassing it.
Add the WHATWG big5 decoder over the vendored index-big5 (18,590 entries),
for both the whole-buffer and streaming decoders. A lead in 0x81-0xFE plus
a trail in 0x40-0x7E or 0xA1-0xFE resolves through the index, covering
Traditional Chinese and the HKSCS extensions including the astral CJK
ideographs. Four pointers decode to a base letter plus a combining mark.
Selected by the big5 / big5-hkscs declaration names.
Closes#103
Extend the GBK two-byte subset to full GB18030: a lead byte followed by
a digit opens a four-byte form whose pointer is mapped through the WHATWG
index-gb18030-ranges linear ranges, reaching the supplementary planes.
The 207 ranges are vendored verbatim. Wired into the whole-buffer and
streaming decoders and the encoding-name table (gb18030/gb-18030).
Closes#102
