quarto-index sort-key level-path probe
A sort key belongs to a level, not to a whole entry
Both back-ends order an index level by level: the LaTeX index tool reads a sort key inside each level of an entry, and the HTML index keys each node on its own printed text. So a key written for a level has to apply to that level wherever it appears — on its own, or above a sub-entry. Were a key instead remembered against the whole entry that declared it, the same printed term would file under two different keys depending on whether a sub-entry happened to follow it, and an index would carry it twice, in two places, printed identically.
The key is declared on the term alone, and the sub-entry written later must inherit it: The Hague has a district Scheveningen.
The other way round — the key declared where the term carries a sub-entry, and the bare term written later: Alpha and later plain Alpha.
A key written for a level must not climb to the level above it. Only the second level is redirected here, so the first keeps its own printed text: Beta and later plain Beta.
A level a declaring mark leaves alone must not shut out the mark that does declare it. The first mark below writes nothing for its first level; the second writes a key for exactly that level, and it is the second that must win, because it is the only declaration either mark makes there: Ccc and later Ccc.
Two skipped levels cannot sit side by side, because !! is the literal ! this syntax gives an author and not two separators. The key below is one level reading !Zed, which is what places this term — not a third level redirected: Literal.
Writing a level's own printed text is how this syntax reaches past a level, and it has to stay a way of skipping rather than become a declaration. The first mark below names Mmm and nn only to reach its third level; the later mark is the one that actually chooses where Mmm files, and it must not be refused for arriving second: Mmm and later Mmm.
Index
- Literal, 1