syntax.dense-punctuation-burst

What it flags

Local bursts of punctuation: a sliding window of grapheme clusters that contains too many qualifying marks (,, ;, :, —, –). Tight clusters of marks signal layered subordination, parenthetical interjections, or list-within-list constructions that are hard to parse for readers with cognitive or attentional difficulties (IFLA easy-to-read guidelines).

Distinct from structure.excessive-commas, which counts commas across an entire sentence. A sentence with 8 commas spread evenly across 200 characters does not trigger here, while a sentence with 3 commas inside a 30-character span does.

At a glance

Detection

Per source line, walk the grapheme stream once and collect the column of every qualifying mark. When a window of window_graphemes graphemes holds min_marks or more marks, emit a burst spanning the first to the last mark in the window, then advance past that last mark so overlapping windows do not double-fire on the same cluster.

Code blocks (fenced and indented) are excluded upstream by the Markdown parser. Sentence terminators (., !, ?) and brackets do not count toward the burst.

Parameters

dev-doc tolerates a 3-mark cluster (often unavoidable in technical lists adjacent to prose). FALC keeps the same density floor as public but widens the window to catch slightly looser bursts.

Known caveats

• The rule operates per source line. A burst that wraps across a hard line break in the source is not detected; in practice this is rare because dense punctuation is also dense in source bytes.
• Em dash (—, U+2014) and en dash (–, U+2013) qualify; the ASCII double-hyphen surrogate (--) does not, on the assumption that authors who care about readability use the proper Unicode forms.

Suppression

See Suppressing diagnostics.

See also

• structure.excessive-commas
• structure.sentence-too-long
• Conditions

References

• Sweller (1988)
• Gibson (1998)

See References for the full bibliography.