@ ProgramNode (location: (1,0)-(1,12))
├── locals: [:str]
└── statements:
    @ StatementsNode (location: (1,0)-(1,12))
    └── body: (length: 1)
        └── @ LocalVariableWriteNode (location: (1,0)-(1,12))
            ├── name: :str
            ├── depth: 0
            ├── name_loc: (1,0)-(1,3) = "str"
            ├── value:
            │   @ StringNode (location: (1,6)-(1,12))
            │   ├── flags: ∅
            │   ├── opening_loc: (1,6)-(1,12) = "<<-XXX"
            │   ├── content_loc: (2,0)-(4,0) = "before\\\r\nafter\r\n"
            │   ├── closing_loc: (4,0)-(5,0) = "XXX\r\n"
            │   └── unescaped: "beforeafter\r\n"
            └── operator_loc: (1,4)-(1,5) = "="
