@ ProgramNode (location: (0...26))
├── locals: []
└── statements:
    @ StatementsNode (location: (0...26))
    └── body: (length: 1)
        └── @ CaseNode (location: (0...26))
            ├── predicate:
            │   @ SymbolNode (location: (5...7))
            │   ├── opening_loc: (5...6) = ":"
            │   ├── value_loc: (6...7) = "x"
            │   ├── closing_loc: ∅
            │   └── unescaped: "x"
            ├── conditions: (length: 1)
            │   └── @ WhenNode (location: (9...17))
            │       ├── keyword_loc: (9...13) = "when"
            │       ├── conditions: (length: 1)
            │       │   └── @ RegularExpressionNode (location: (14...17))
            │       │       ├── opening_loc: (14...15) = "/"
            │       │       ├── content_loc: (15...16) = "x"
            │       │       ├── closing_loc: (16...17) = "/"
            │       │       ├── unescaped: "x"
            │       │       └── flags: ∅
            │       └── statements: ∅
            ├── consequent: ∅
            ├── case_keyword_loc: (0...4) = "case"
            └── end_keyword_loc: (23...26) = "end"
