Concept

Traversal order — where it appears

The sequence in which a walk visits the things it is walking, when that sequence carries information the walk would otherwise have to store. Getting it wrong produces a short answer rather than a wrong one, which no test of the output can see.

Named by 3 essays across 3 fields — each of them below, with the objects they name alongside it.

From the right, two of sixteen

Run the same sweep in the opposite direction and every occurrence it produces lands behind its own cursor. It reports two of sixteen, every one of them genuinely there, and nothing about the answer says fourteen are missing.

floors · Parse

Every copy points right

A greedy self-referential parse chooses each phrase's source from text already produced, so an occurrence copied from another lies strictly to its right. That one fact removes a visited set from a propagation, exactly as a left-first walk removed an array one strand ago.

structures · Parse

The same occurrences, less bookkeeping

Two traversals examine identically many phrases and report identically many occurrences. What differs is that one holds every occurrence found so far in a set and the other holds an ordered list and a cursor.

indexes · Parse

Named alongside it

The objects these essays reach for when they reach for this one.

Phrase index Propagation Secondary occurrence Lempel ziv parse Visited set Correctness Previous occurrence chain Rejection test Silent failure Working memory

All concepts