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).
Closes#93. Recovery moves into a recovering mode on EventReader, so malformed
input is repaired in place rather than dropped to the next markup boundary:
- A duplicate attribute is recorded and the later occurrence dropped, keeping the
element. <a id='1' id='2'>y</a> now reads as <a id="1">y</a> with one
diagnostic (was an empty tree with three).
- A mismatched or unexpected end tag pops the open stack to the matching ancestor,
implicitly closing the elements nested inside it. <a><b><c>x</b></a> reads as
<a><b><c>x</c></b></a> with a single diagnostic.
- Pre-root junk reports "unexpected character" instead of the misleading
"content after the root element".
In recovering mode next() no longer throws: it records a Diagnostic and emits
best-effort events, popping to a match on a mismatch and stopping on truncation
so the builder closes what is open. The strict path is unchanged. readRecovering
becomes a plain non-throwing drain that takes the reader's diagnostics. Recovery
stays deterministic; new tests pin the kept-element and pop-to-match results.
Slice 2 of #92. Add PureXML.read, a deterministic recovering reader: it never
throws and never traps, returning the maximal best-effort tree plus one located
Diagnostic per problem.
- ReadResult { node, diagnostics } is the Equatable result type, so a
deterministic read can be compared whole.
- Diagnostic carries a message and a structured source Mark; a thrown ParseError
maps to one directly (ParseError.mark exposes the position each case carries).
- The reader resynchronizes after a failure (EventReader.recover(from:)):
progress-aware, so a failure that already consumed the bad construct retries
from there, while a stuck failure skips to the next markup start; it always
advances when input remains, guaranteeing termination.
- The tree builder assembles leniently: elements left open by truncation are
closed, an end tag with no open element is dropped. Well-formed input yields
exactly parse(_:)'s tree with no diagnostics.
Tests pin exact trees and diagnostics for truncation, mismatched tags, and stray
junk, prove determinism (same bytes give an identical ReadResult), and fuzz 400
seeded inputs (arbitrary plus truncated valid docs) asserting no crash.
Recovery here is resync-based; finer in-reader recovery (keep the element on a
duplicate attribute, pop to a matching open tag) is the next slice.
