Relationship Pattern

A relationship pattern is a sequence of subject patterns separated by combinators.

Subjects. By default, the subjects of a relationship pattern are the subjects of the last subject pattern in the relationship pattern.

Subject Pattern

A subject pattern is any pattern that can be related by a combinator. There are two kinds of subject patterns: instance patterns and branch patterns.

Combinator

A combinator is punctuation that represents a relationship between two views. Whitespace may appear on either side of a combinator.

• s1 s2 — descendant combinator — matches a view s2 that is a descendant of view s1. The combinator is the whitespace between s1 and s2.

• s1>s2 — child combinator — matches a view s2 that is a subview of view s1.

• s1~s2 — sibling combinator — matches a view s2 that has a sibling view s1.

Branch Pattern

A branch pattern is a relationship pattern enclosed in parentheses.

• (s1 s2) — matches a view s1 that has a descendant view s2.

Subjects. A branch pattern's subjects are the subjects of the first subject pattern in the enclosed relationship pattern.