7. Structural Processing Model

§5 yields a flat element stream; §6 classifies each directive. This section defines the structure built on top: how openers pair with closers, how containers nest, how forward references resolve, and how the result serializes back to source byte-for-byte.

7.1 Pairing

Some constructs are paired: an opener and a matching closer with content between them. The paired families are:

• block layout containers — ［＃ここから…］ / ［＃ここで…終わり］ (§6.6);
• 罫囲み — ［＃罫囲み］ / ［＃罫囲み終わり］ (§6.7);
• 割り注 — ［＃割り注］ / ［＃割り注終わり］ (§6.8); and
• the 傍点/傍線 range form — ［＃傍点］ / ［＃傍点終わり］ (§6.2).

Pairing uses a stack: each opener is pushed; each closer pops the nearest open of a compatible family and forms a pair governing the content between them. A processor MUST pair by family, not by exact variant, so that e.g. a 2字下げ opener pairs with a plain 字下げ終わり closer.

7.2 Mismatch and recovery

• A closer whose family differs from the popped opener raises mismatched-container-close; the opener is auto-closed at the closer and the pair is keyed by the opener's family (recovery).
• Within the 傍点/傍線 range family, a 点-vs-線 family disagreement raises mismatched-bouten-container (§6.2); the run is keyed to the opener's variant.
• A closer with no open on the stack, or an opener never closed, is handled per unmatched-close / unclosed-bracket; the affected marker degrades but its bytes are preserved.

7.3 Block vs inline; nesting

A paired construct is block or inline:

• Block containers (block layout, 罫囲み) govern whole lines and may nest; rendering wraps them as block elements. Breaks (§6.9) persist across a block container (print typography), so a break inside one is not flagged.
• Inline ranges (傍点/傍線 range, 割り注) attach within a line and do not introduce block structure. The corpus shows these never span a line in practice.

Containers nest by the stack discipline of §7.1; an inner pair closes before its outer pair.

7.4 Single-line containers

A single-line layout directive (［＃地付き］, ［＃2字下げ］, §6.6) has no closer: it governs the remainder of its line only and is modelled as a zero-width marker, not a wrapping container. Consequently a page or section break sharing that line, or a break inside a 割り注 range, drops the governed scope and raises break-in-single-line-container (§6.9).

7.5 Forward-reference resolution

Some directives name a target by quoting it and look backwards in the already-seen text to find the run they apply to:

• ［＃「X」に傍点］ and its variants (§6.2),
• ［＃「X」は縦中横］ (§6.3),
• heading hints ［＃「X」は…見出し］ (§6.10), and
• 「ママ」/textual-note annotations (§6.14).

Resolution rule: a processor scans the text preceding the directive (back to the start of the current line, or the document per the construct) for the most recent occurrence of the quoted target X, and applies the construct to that run. The matched run may be adjacent to the directive (the redundant explicit form 平和［＃「平和」に傍点］) or lie earlier in the same base run (太字の［＃「太字」は太字］ — の intervenes); in both cases the construct is applied in place to that occurrence, and the directive round-trips unchanged (§7.6).

• The look-back is over the base text: ruby readings (《…》) and the explicit-base ｜ marker are not part of what X matches against. A heading whose title carries ruby — ○　両頭《りやうとう》の蛇《へび》［＃「○　両頭の蛇」は中見出し］ — quotes the ruby-stripped target ○　両頭の蛇, which a processor resolves against the ruby-stripped run ○　両頭の蛇.

• If X does not occur in the look-back, the directive degrades to a generic annotation and raises the family's "target not found" diagnostic (e.g. tcy-target-not-found).

• If X occurs more than once, the chosen run may be unintended; a processor raises the family's "ambiguous" diagnostic where defined (e.g. bouten-target-ambiguous) and applies the construct to the match its look-back selects.

• If X resolves but the matched run cannot be styled in place — it is a ruby base (bouten-over-ruby is not representable as a text-only leaf), lies on an earlier line, sits inside another construct, or is one of several quoted targets — a processor keeps the directive, leaves the run unstyled, and raises forward-referent-not-stylable. The directive still round-trips unchanged (§7.6).

• The redundant explicit form 平和［＃「平和」に傍点］ (the target literal immediately precedes the directive) is common and MUST round-trip unchanged (§7.6).

7.6 Serialization round-trip

A processor that serializes MUST be a fixed point: re-parsing a serialized result yields the same structure, and serializing again yields the same bytes. Normalization (§4) is loss-free for this reason — the serializer reconstructs 〔…〕 accent spans, the ｜ of an explicit ruby base, the literal target of a redundant forward reference, and the original directive strings. The serialize projection of each conformance vector pins this.