`PureXML.XInclude.process` rebuilt the tree recursively (`process →
processElement → process`), so a deeply-nested document overflowed the stack
one native frame per element level, even with no includes present. It now
drives an explicit work stack: each branch gathers its processed children into
a reference accumulator, then a deferred build step assembles the node. The
`xml:base`, inclusion-chain depth (bounded by `maxDepth`), and cycle-detection
visited set thread down per context exactly as before; an include splices its
(or its fallback's) content in place by pushing the loaded nodes back onto the
stack.
Behavior is unchanged: the XInclude/XPointer conformance corpus and the
fallback, xpointer, cycle, and xml:base cases all pass. A 50000-deep document,
with or without an include at its base, now processes without crashing, guarded
by `XIncludeDepthSafetyTests`. Part of #350.
Three XInclude gaps from the audit:
- accept / accept-language / encoding are surfaced to the loader via a new
XIncludeRequest and a process(_:base:loading:) overload, so a loader can
honor content negotiation. The existing loadingURI form is kept.
- Cycle detection tracks the visited (resolved-URI) set along the current
inclusion chain and raises XIncludeError.cycle, instead of relying only
on the depth backstop; a non-cyclic diamond include is not flagged.
- parse="text" combined with an xpointer is rejected
(XIncludeError.textWithFragment), since a fragment cannot select within
unparsed text.
xpointer range() inclusion still depends on the XPointer range() scheme
(tracked in the XPointer issue).
Part of #87
Add the PureXML.XInclude namespace: RFC 3986 reference resolution
(URIReference with dot-segment removal) and an xi:include processor over the
value tree. href resolves against the base and in-scope xml:base; parse=xml
includes the document element or an xpointer() fragment (via PureXML.XPointer),
parse=text includes raw text, and a failed load uses xi:fallback or errors.
Includes nest. No I/O is done internally: fetching is only through the
injected loadingURI closure, so the default fetches nothing.
Closes#48Closes#49Closes#50Closes#51Closes#24
