@ ProgramNode (location: (1,0)-(21,31))
├── locals: []
└── statements:
    @ StatementsNode (location: (1,0)-(21,31))
    └── body: (length: 11)
        ├── @ WhileNode (location: (1,0)-(1,18))
        │   ├── keyword_loc: (1,0)-(1,5) = "while"
        │   ├── closing_loc: (1,15)-(1,18) = "end"
        │   ├── predicate:
        │   │   @ TrueNode (location: (1,6)-(1,10))
        │   ├── statements:
        │   │   @ StatementsNode (location: (1,12)-(1,13))
        │   │   └── body: (length: 1)
        │   │       └── @ IntegerNode (location: (1,12)-(1,13))
        │   │           └── flags: decimal
        │   └── flags: ∅
        ├── @ WhileNode (location: (3,0)-(3,12))
        │   ├── keyword_loc: (3,2)-(3,7) = "while"
        │   ├── closing_loc: ∅
        │   ├── predicate:
        │   │   @ TrueNode (location: (3,8)-(3,12))
        │   ├── statements:
        │   │   @ StatementsNode (location: (3,0)-(3,1))
        │   │   └── body: (length: 1)
        │   │       └── @ IntegerNode (location: (3,0)-(3,1))
        │   │           └── flags: decimal
        │   └── flags: ∅
        ├── @ WhileNode (location: (5,0)-(5,16))
        │   ├── keyword_loc: (5,6)-(5,11) = "while"
        │   ├── closing_loc: ∅
        │   ├── predicate:
        │   │   @ TrueNode (location: (5,12)-(5,16))
        │   ├── statements:
        │   │   @ StatementsNode (location: (5,0)-(5,5))
        │   │   └── body: (length: 1)
        │   │       └── @ BreakNode (location: (5,0)-(5,5))
        │   │           ├── arguments: ∅
        │   │           └── keyword_loc: (5,0)-(5,5) = "break"
        │   └── flags: ∅
        ├── @ WhileNode (location: (7,0)-(7,15))
        │   ├── keyword_loc: (7,5)-(7,10) = "while"
        │   ├── closing_loc: ∅
        │   ├── predicate:
        │   │   @ TrueNode (location: (7,11)-(7,15))
        │   ├── statements:
        │   │   @ StatementsNode (location: (7,0)-(7,4))
        │   │   └── body: (length: 1)
        │   │       └── @ NextNode (location: (7,0)-(7,4))
        │   │           ├── arguments: ∅
        │   │           └── keyword_loc: (7,0)-(7,4) = "next"
        │   └── flags: ∅
        ├── @ WhileNode (location: (9,0)-(9,17))
        │   ├── keyword_loc: (9,7)-(9,12) = "while"
        │   ├── closing_loc: ∅
        │   ├── predicate:
        │   │   @ TrueNode (location: (9,13)-(9,17))
        │   ├── statements:
        │   │   @ StatementsNode (location: (9,0)-(9,6))
        │   │   └── body: (length: 1)
        │   │       └── @ ReturnNode (location: (9,0)-(9,6))
        │   │           ├── keyword_loc: (9,0)-(9,6) = "return"
        │   │           └── arguments: ∅
        │   └── flags: ∅
        ├── @ WhileNode (location: (11,0)-(11,21))
        │   ├── keyword_loc: (11,11)-(11,16) = "while"
        │   ├── closing_loc: ∅
        │   ├── predicate:
        │   │   @ CallNode (location: (11,17)-(11,21))
        │   │   ├── receiver: ∅
        │   │   ├── call_operator_loc: ∅
        │   │   ├── message_loc: (11,17)-(11,21) = "bar?"
        │   │   ├── opening_loc: ∅
        │   │   ├── arguments: ∅
        │   │   ├── closing_loc: ∅
        │   │   ├── block: ∅
        │   │   ├── flags: ∅
        │   │   └── name: :bar?
        │   ├── statements:
        │   │   @ StatementsNode (location: (11,0)-(11,10))
        │   │   └── body: (length: 1)
        │   │       └── @ CallNode (location: (11,0)-(11,10))
        │   │           ├── receiver: ∅
        │   │           ├── call_operator_loc: ∅
        │   │           ├── message_loc: (11,0)-(11,3) = "foo"
        │   │           ├── opening_loc: ∅
        │   │           ├── arguments:
        │   │           │   @ ArgumentsNode (location: (11,4)-(11,10))
        │   │           │   ├── arguments: (length: 2)
        │   │           │   │   ├── @ SymbolNode (location: (11,4)-(11,6))
        │   │           │   │   │   ├── opening_loc: (11,4)-(11,5) = ":"
        │   │           │   │   │   ├── value_loc: (11,5)-(11,6) = "a"
        │   │           │   │   │   ├── closing_loc: ∅
        │   │           │   │   │   └── unescaped: "a"
        │   │           │   │   └── @ SymbolNode (location: (11,8)-(11,10))
        │   │           │   │       ├── opening_loc: (11,8)-(11,9) = ":"
        │   │           │   │       ├── value_loc: (11,9)-(11,10) = "b"
        │   │           │   │       ├── closing_loc: ∅
        │   │           │   │       └── unescaped: "b"
        │   │           │   └── flags: ∅
        │   │           ├── closing_loc: ∅
        │   │           ├── block: ∅
        │   │           ├── flags: ∅
        │   │           └── name: :foo
        │   └── flags: ∅
        ├── @ WhileNode (location: (13,0)-(13,50))
        │   ├── keyword_loc: (13,0)-(13,5) = "while"
        │   ├── closing_loc: (13,47)-(13,50) = "end"
        │   ├── predicate:
        │   │   @ DefNode (location: (13,6)-(13,38))
        │   │   ├── name: :foo
        │   │   ├── name_loc: (13,15)-(13,18) = "foo"
        │   │   ├── receiver:
        │   │   │   @ SelfNode (location: (13,10)-(13,14))
        │   │   ├── parameters:
        │   │   │   @ ParametersNode (location: (13,19)-(13,33))
        │   │   │   ├── requireds: (length: 0)
        │   │   │   ├── optionals: (length: 1)
        │   │   │   │   └── @ OptionalParameterNode (location: (13,19)-(13,33))
        │   │   │   │       ├── name: :a
        │   │   │   │       ├── name_loc: (13,19)-(13,20) = "a"
        │   │   │   │       ├── operator_loc: (13,21)-(13,22) = "="
        │   │   │   │       └── value:
        │   │   │   │           @ CallNode (location: (13,23)-(13,33))
        │   │   │   │           ├── receiver: ∅
        │   │   │   │           ├── call_operator_loc: ∅
        │   │   │   │           ├── message_loc: (13,23)-(13,26) = "tap"
        │   │   │   │           ├── opening_loc: ∅
        │   │   │   │           ├── arguments: ∅
        │   │   │   │           ├── closing_loc: ∅
        │   │   │   │           ├── block:
        │   │   │   │           │   @ BlockNode (location: (13,27)-(13,33))
        │   │   │   │           │   ├── locals: []
        │   │   │   │           │   ├── parameters: ∅
        │   │   │   │           │   ├── body: ∅
        │   │   │   │           │   ├── opening_loc: (13,27)-(13,29) = "do"
        │   │   │   │           │   └── closing_loc: (13,30)-(13,33) = "end"
        │   │   │   │           ├── flags: ∅
        │   │   │   │           └── name: :tap
        │   │   │   ├── rest: ∅
        │   │   │   ├── posts: (length: 0)
        │   │   │   ├── keywords: (length: 0)
        │   │   │   ├── keyword_rest: ∅
        │   │   │   └── block: ∅
        │   │   ├── body: ∅
        │   │   ├── locals: [:a]
        │   │   ├── def_keyword_loc: (13,6)-(13,9) = "def"
        │   │   ├── operator_loc: (13,14)-(13,15) = "."
        │   │   ├── lparen_loc: ∅
        │   │   ├── rparen_loc: ∅
        │   │   ├── equal_loc: ∅
        │   │   └── end_keyword_loc: (13,35)-(13,38) = "end"
        │   ├── statements:
        │   │   @ StatementsNode (location: (13,40)-(13,45))
        │   │   └── body: (length: 1)
        │   │       └── @ BreakNode (location: (13,40)-(13,45))
        │   │           ├── arguments: ∅
        │   │           └── keyword_loc: (13,40)-(13,45) = "break"
        │   └── flags: ∅
        ├── @ WhileNode (location: (15,0)-(15,47))
        │   ├── keyword_loc: (15,0)-(15,5) = "while"
        │   ├── closing_loc: (15,44)-(15,47) = "end"
        │   ├── predicate:
        │   │   @ ClassNode (location: (15,6)-(15,35))
        │   │   ├── locals: [:a]
        │   │   ├── class_keyword_loc: (15,6)-(15,11) = "class"
        │   │   ├── constant_path:
        │   │   │   @ ConstantReadNode (location: (15,12)-(15,15))
        │   │   │   └── name: :Foo
        │   │   ├── inheritance_operator_loc: ∅
        │   │   ├── superclass: ∅
        │   │   ├── body:
        │   │   │   @ StatementsNode (location: (15,16)-(15,30))
        │   │   │   └── body: (length: 1)
        │   │   │       └── @ LocalVariableWriteNode (location: (15,16)-(15,30))
        │   │   │           ├── name: :a
        │   │   │           ├── depth: 0
        │   │   │           ├── name_loc: (15,16)-(15,17) = "a"
        │   │   │           ├── value:
        │   │   │           │   @ CallNode (location: (15,20)-(15,30))
        │   │   │           │   ├── receiver: ∅
        │   │   │           │   ├── call_operator_loc: ∅
        │   │   │           │   ├── message_loc: (15,20)-(15,23) = "tap"
        │   │   │           │   ├── opening_loc: ∅
        │   │   │           │   ├── arguments: ∅
        │   │   │           │   ├── closing_loc: ∅
        │   │   │           │   ├── block:
        │   │   │           │   │   @ BlockNode (location: (15,24)-(15,30))
        │   │   │           │   │   ├── locals: []
        │   │   │           │   │   ├── parameters: ∅
        │   │   │           │   │   ├── body: ∅
        │   │   │           │   │   ├── opening_loc: (15,24)-(15,26) = "do"
        │   │   │           │   │   └── closing_loc: (15,27)-(15,30) = "end"
        │   │   │           │   ├── flags: ∅
        │   │   │           │   └── name: :tap
        │   │   │           └── operator_loc: (15,18)-(15,19) = "="
        │   │   ├── end_keyword_loc: (15,32)-(15,35) = "end"
        │   │   └── name: :Foo
        │   ├── statements:
        │   │   @ StatementsNode (location: (15,37)-(15,42))
        │   │   └── body: (length: 1)
        │   │       └── @ BreakNode (location: (15,37)-(15,42))
        │   │           ├── arguments: ∅
        │   │           └── keyword_loc: (15,37)-(15,42) = "break"
        │   └── flags: ∅
        ├── @ WhileNode (location: (17,0)-(17,48))
        │   ├── keyword_loc: (17,0)-(17,5) = "while"
        │   ├── closing_loc: (17,45)-(17,48) = "end"
        │   ├── predicate:
        │   │   @ SingletonClassNode (location: (17,6)-(17,36))
        │   │   ├── locals: []
        │   │   ├── class_keyword_loc: (17,6)-(17,11) = "class"
        │   │   ├── operator_loc: (17,12)-(17,14) = "<<"
        │   │   ├── expression:
        │   │   │   @ SelfNode (location: (17,15)-(17,19))
        │   │   ├── body:
        │   │   │   @ StatementsNode (location: (17,21)-(17,31))
        │   │   │   └── body: (length: 1)
        │   │   │       └── @ CallNode (location: (17,21)-(17,31))
        │   │   │           ├── receiver: ∅
        │   │   │           ├── call_operator_loc: ∅
        │   │   │           ├── message_loc: (17,21)-(17,24) = "tap"
        │   │   │           ├── opening_loc: ∅
        │   │   │           ├── arguments: ∅
        │   │   │           ├── closing_loc: ∅
        │   │   │           ├── block:
        │   │   │           │   @ BlockNode (location: (17,25)-(17,31))
        │   │   │           │   ├── locals: []
        │   │   │           │   ├── parameters: ∅
        │   │   │           │   ├── body: ∅
        │   │   │           │   ├── opening_loc: (17,25)-(17,27) = "do"
        │   │   │           │   └── closing_loc: (17,28)-(17,31) = "end"
        │   │   │           ├── flags: ∅
        │   │   │           └── name: :tap
        │   │   └── end_keyword_loc: (17,33)-(17,36) = "end"
        │   ├── statements:
        │   │   @ StatementsNode (location: (17,38)-(17,43))
        │   │   └── body: (length: 1)
        │   │       └── @ BreakNode (location: (17,38)-(17,43))
        │   │           ├── arguments: ∅
        │   │           └── keyword_loc: (17,38)-(17,43) = "break"
        │   └── flags: ∅
        ├── @ WhileNode (location: (19,0)-(19,52))
        │   ├── keyword_loc: (19,0)-(19,5) = "while"
        │   ├── closing_loc: (19,49)-(19,52) = "end"
        │   ├── predicate:
        │   │   @ SingletonClassNode (location: (19,6)-(19,40))
        │   │   ├── locals: [:a]
        │   │   ├── class_keyword_loc: (19,6)-(19,11) = "class"
        │   │   ├── operator_loc: (19,12)-(19,14) = "<<"
        │   │   ├── expression:
        │   │   │   @ SelfNode (location: (19,15)-(19,19))
        │   │   ├── body:
        │   │   │   @ StatementsNode (location: (19,21)-(19,35))
        │   │   │   └── body: (length: 1)
        │   │   │       └── @ LocalVariableWriteNode (location: (19,21)-(19,35))
        │   │   │           ├── name: :a
        │   │   │           ├── depth: 0
        │   │   │           ├── name_loc: (19,21)-(19,22) = "a"
        │   │   │           ├── value:
        │   │   │           │   @ CallNode (location: (19,25)-(19,35))
        │   │   │           │   ├── receiver: ∅
        │   │   │           │   ├── call_operator_loc: ∅
        │   │   │           │   ├── message_loc: (19,25)-(19,28) = "tap"
        │   │   │           │   ├── opening_loc: ∅
        │   │   │           │   ├── arguments: ∅
        │   │   │           │   ├── closing_loc: ∅
        │   │   │           │   ├── block:
        │   │   │           │   │   @ BlockNode (location: (19,29)-(19,35))
        │   │   │           │   │   ├── locals: []
        │   │   │           │   │   ├── parameters: ∅
        │   │   │           │   │   ├── body: ∅
        │   │   │           │   │   ├── opening_loc: (19,29)-(19,31) = "do"
        │   │   │           │   │   └── closing_loc: (19,32)-(19,35) = "end"
        │   │   │           │   ├── flags: ∅
        │   │   │           │   └── name: :tap
        │   │   │           └── operator_loc: (19,23)-(19,24) = "="
        │   │   └── end_keyword_loc: (19,37)-(19,40) = "end"
        │   ├── statements:
        │   │   @ StatementsNode (location: (19,42)-(19,47))
        │   │   └── body: (length: 1)
        │   │       └── @ BreakNode (location: (19,42)-(19,47))
        │   │           ├── arguments: ∅
        │   │           └── keyword_loc: (19,42)-(19,47) = "break"
        │   └── flags: ∅
        └── @ WhileNode (location: (21,0)-(21,31))
            ├── keyword_loc: (21,0)-(21,5) = "while"
            ├── closing_loc: (21,28)-(21,31) = "end"
            ├── predicate:
            │   @ DefNode (location: (21,6)-(21,26))
            │   ├── name: :foo
            │   ├── name_loc: (21,10)-(21,13) = "foo"
            │   ├── receiver: ∅
            │   ├── parameters: ∅
            │   ├── body:
            │   │   @ StatementsNode (location: (21,16)-(21,26))
            │   │   └── body: (length: 1)
            │   │       └── @ CallNode (location: (21,16)-(21,26))
            │   │           ├── receiver: ∅
            │   │           ├── call_operator_loc: ∅
            │   │           ├── message_loc: (21,16)-(21,19) = "bar"
            │   │           ├── opening_loc: ∅
            │   │           ├── arguments: ∅
            │   │           ├── closing_loc: ∅
            │   │           ├── block:
            │   │           │   @ BlockNode (location: (21,20)-(21,26))
            │   │           │   ├── locals: []
            │   │           │   ├── parameters: ∅
            │   │           │   ├── body: ∅
            │   │           │   ├── opening_loc: (21,20)-(21,22) = "do"
            │   │           │   └── closing_loc: (21,23)-(21,26) = "end"
            │   │           ├── flags: ∅
            │   │           └── name: :bar
            │   ├── locals: []
            │   ├── def_keyword_loc: (21,6)-(21,9) = "def"
            │   ├── operator_loc: ∅
            │   ├── lparen_loc: ∅
            │   ├── rparen_loc: ∅
            │   ├── equal_loc: (21,14)-(21,15) = "="
            │   └── end_keyword_loc: ∅
            ├── statements: ∅
            └── flags: ∅