FA-80469 / Bidirectional text layout / Member archive

Implicit level runs: run level equality · case 04

Runs at levels 1 and 3 are merged.

Member previewVariant 4 · 3 implementations · 8 checks per implementation

Case contract

Input [resolved classes L/R/EN/AN, embedding levels]. At even levels R goes up one and AN/EN up two; at odd levels L, EN and AN go up one. Return level runs [start, end exclusive, level] of equal final levels.

Why this case matters

Mixed right-to-left and left-to-right text must resolve levels and visual order exactly, or words, numbers and carets land in the wrong place.

One recorded failure

Sample boundary fixture

This sample comes from the broken implementation of a controlled reproducer.

Boundary fixture	Actual	Expected	Outcome
regression: run level equality	`[[0, 1, 3], [1, 2, 4], [2, 3, 1], [3, 4, 2], [4, 6, 1], [6, 8, 0]]`	`[[0, 1, 3], [1, 2, 4], [2, 3, 1], [3, 4, 2], [4, 6, 1], [6, 7, 0], [7, 8, 2]]`	Failed

MEMBER ARCHIVE

The complete case is available to members.

This record includes three runnable implementations, regression fixtures, execution results, and source hashes.

Member access is invitation-based. Sign in with your invited account to inspect the sources.