@ ProgramNode (location: (0...10))
├── locals: []
└── statements:
    @ StatementsNode (location: (0...10))
    └── body: (length: 1)
        └── @ RegularExpressionNode (location: (0...10))
            ├── opening_loc: (0...1) = "/"
            ├── content_loc: (1...7) = "source"
            ├── closing_loc: (7...10) = "/im"
            ├── unescaped: "source"
            └── flags: ignore_case, multi_line
