structure.italic-span-long

Experimental in v0.2.x. Off by default; opt in via --experimental structure.italic-span-long or [experimental] enabled = ["structure.italic-span-long"] in lucid-lint.toml. Flips to Stable at the v0.3 cut as part of the F-experimental-rule-status cohort flip. See Conditions for the dyslexia condition tag that gates this rule under user-active conditions.

What it flags

Italic spans (*…* / _…_) longer than a configurable word threshold. Slanted glyphs degrade letter-shape recognition for readers with dyslexia — a robust finding behind the British Dyslexia Association’s recommendation to keep italic emphasis to a short phrase rather than running a full sentence in italics. Long italic runs also harm scanability for readers whose attention is already taxed (fatigue, second-language reading, low-vision conditions).

At a glance

Detection

Walks the typed inline tree captured on each Paragraph (F143 substrate) and flags every Inline::Emphasis span whose visible word count exceeds the per-profile threshold. Code blocks and inline code are excluded by the parser, so an italic span inside a code fence never fires. Strong (**bold**) does not trigger this rule — only emphasis (*italic* / _italic_).

The diagnostic location points at the opening delimiter, so the squiggle in your editor lands on the visible * or _ rather than an arbitrary column inside the paragraph.

Parameters

Tune via lucid-lint.toml:

[rules."structure.italic-span-long"]
max_words = 6

Examples

English

Before (flagged):

The team eventually concluded that the proposed migration plan would require careful coordination across three regional offices and an extended freeze window before any deployment could begin.

What lucid-lint check --profile public --experimental structure.italic-span-long --conditions dyslexia reports:

warning input.md:1:36 Italic span is 17 words long (maximum 8). Long italic runs strain dyslexic readers; consider shortening the emphasized phrase or removing the italics. [structure.italic-span-long]

After (your rewrite):

The team eventually concluded that the proposed migration plan would require careful coordination. Three regional offices and an extended freeze window are prerequisites before any deployment.

The italics now mark a single load-bearing word — the kind of emphasis the BDA style guide endorses.

French

Before (flagged):

L’équipe a fini par conclure que le plan de migration proposé nécessiterait une coordination soignée entre trois bureaux régionaux et une fenêtre de gel prolongée avant tout déploiement.

What lucid-lint check --profile public --experimental structure.italic-span-long --conditions dyslexia reports:

warning input.md:1:35 Italic span is 18 words long (maximum 8). Long italic runs strain dyslexic readers; consider shortening the emphasized phrase or removing the italics. [structure.italic-span-long]

After (your rewrite):

L’équipe a fini par conclure que le plan de migration nécessiterait une coordination soignée. Trois bureaux régionaux et une fenêtre de gel prolongée sont indispensables avant tout déploiement.

Suppression

See Suppressing diagnostics for the inline and block forms. Inline disable also works on this rule:

<!-- lucid-lint disable-next-line structure.italic-span-long -->
A *deliberately long italic span that the rule would normally flag* lives here.

See also

• Conditions — the dyslexia tag that gates this rule.
• F-experimental-rule-status — experimental rule status — substrate that lets this rule ship in v0.2.x without affecting default scores.
• F143 — inline AST layer — substrate that exposes emphasis-span boundaries to this rule.

References

• British Dyslexia Association — Dyslexia Style Guide (2018). Recommends keeping italics to short phrases for letter-shape recognition.
• Rello & Baeza-Yates (2013) — broader academic context on dyslexia-friendly typography.

See References for the full bibliography.