Word Break - Extend Num Let

Extend Num Let is a classification for certain numeric and alphabetic characters, such as digits, ideographic numbers, and currency symbols, that are treated as a seamless unit when determining word boundaries. It specifically allows a sequence of these characters, like “123” or “Ⅷ”, to remain unbroken, even when combined with other numeric forms or with letter-like marks. This behavior prevents unintended splits in cases like “第123号”, where the numeral and its surrounding context stay together. It also interacts with adjacent classes, such as allowing the sequence to continue across a following “Extend” or “Format” character without creating a new word break. Essentially, it ensures that numbers and similar symbols behave as a single cohesive entity, aiding in consistent text segmentation for applications like search and spell checking.