@ ProgramNode (location: (1,0)-(1,28))
├── locals: []
└── statements:
    @ StatementsNode (location: (1,0)-(1,28))
    └── body: (length: 1)
        └── @ CaseNode (location: (1,0)-(1,28))
            ├── predicate: ∅
            ├── conditions: (length: 1)
            │   └── @ WhenNode (location: (1,6)-(1,23))
            │       ├── keyword_loc: (1,6)-(1,10) = "when"
            │       ├── conditions: (length: 1)
            │       │   └── @ RegularExpressionNode (location: (1,11)-(1,23))
            │       │       ├── flags: ∅
            │       │       ├── opening_loc: (1,11)-(1,14) = "%r%"
            │       │       ├── content_loc: (1,14)-(1,22) = "blahblah"
            │       │       ├── closing_loc: (1,22)-(1,23) = "%"
            │       │       └── unescaped: "blahblah"
            │       └── statements: ∅
            ├── consequent: ∅
            ├── case_keyword_loc: (1,0)-(1,4) = "case"
            └── end_keyword_loc: (1,25)-(1,28) = "end"
