@ ProgramNode (location: (0...9))
├── locals: []
└── statements:
    @ StatementsNode (location: (0...9))
    └── body: (length: 1)
        └── @ GlobalVariableWriteNode (location: (0...9))
            ├── name: :$var
            ├── name_loc: (0...4) = "$var"
            ├── value:
            │   @ IntegerNode (location: (7...9))
            │   └── flags: decimal
            └── operator_loc: (5...6) = "="
