6.16 Superscript, subscript, and side glyphs (上付き・下付き・小書き)

Synopsis

Four forward-reference families set a short run as a small glyph offset from the baseline rather than changing its weight or slant (§6.12):

• 上付き小文字 (superscript) and 下付き小文字 (subscript) — the 横組み (horizontal-writing) raised/lowered small characters of mathematics (exponents) and chemistry (formula indices).
• 行右小書き and 行左小書き — the 縦組み (vertical-writing) small glyphs set to the right or left of the line.

All four are documented on the official 注記一覧 "その他" page ([AOZORA-ANNOTATION], etc.html). They share the forward-reference shape and the は particle with 太字/斜体 (§6.12) and yield the same emphasis node, so the spec groups them as one inline family distinct from bouten (§6.2).

Notation

Each family is forward reference only — quote the target; the treatment applies to the most recent preceding occurrence (§7.5). The particle is は.

script-glyph = target "［＃「" target "」は" keyword "］"
keyword      = "上付き小文字" / "下付き小文字" / "行右小書き" / "行左小書き"

ｅ２［＃「２」は上付き小文字］
Ｈ２［＃「２」は下付き小文字］
あい［＃「い」は行右小書き］
あい［＃「い」は行左小書き］

Unlike 太字/斜体 there is no bare inline range and no ここから/ここで block range for these families: the official guide gives only the forward-reference form, and the corpus attests only it.

Parameters

• kind — one of 上付き小文字 / 下付き小文字 / 行右小書き / 行左小書き.
• target — the single quoted run to treat. As with §6.12, the form names exactly one target; a multi-quote body is not a recognised shape and degrades (§6.14).

Semantics

• Each form resolves its target by the look-back rule of §7.5 and yields an emphasis node over that run. It is an inline construct.

• The node carries the kind so serialization (§7.6) can reconstruct the source directive, including the redundant preceding target copy, byte-exact.

• Reference rendering (§8):

  • 上付き小文字 → <sup class="aozora-uwatsuki">…</sup>
  • 下付き小文字 → <sub class="aozora-shitatsuki">…</sub>
  • 行右小書き → <span class="aozora-kogaki-right">…</span>
  • 行左小書き → <span class="aozora-kogaki-left">…</span>

  The <sup> / <sub> elements give super- and sub-script their conventional horizontal rendering; the 小書き families, which are positional in vertical writing, render as side <span>s a stylesheet can place. None collides with the <b> / <i> of §6.12, the <em> of bouten (§6.2), or the <ruby> of §6.1.

Error conditions

• Target with no referent — a は… directive whose quoted target does not occur in the preceding text has no earlier run to treat, so the quoted target is itself the treated run: a self-contained forward reference, rendered <sup> / <sub> / side <span>. Serialization reconstructs the directive byte-exact (§7.6); no input is lost (parallel to the 太字/斜体 rule, §6.12).

Conformance vectors

superscript_forward, subscript_forward, side_glyph_right, side_glyph_left, superscript_forward_no_referent, subscript_forward_no_referent, side_glyph_right_no_referent, side_glyph_left_no_referent (under conformance/vectors/).