Date pattern railroad
PlantUML regex block with named groups, character sets, repetition and a negative lookahead.
Scope: Static regex syntax diagram and structural exploration; no embedded regex execution engine.
Preview
Source
regex-date.puml
text/plain
@startregex
title ISO date with optional time
(?<year>\d{4})-(?<month>0[1-9]|1[0-2])-(?<day>\d{2})(?:T\d{2}:\d{2})?(?!\d)
@endregex