======= AST Display =========================
Package
  ClassDeclList [1]
  . ClassDecl
  .   "B" classname
  .   FieldDeclList [0]
  .   MethodDeclList [1]
  .   . (public) MethodDecl
  .   .   VOID BaseType
  .   .   "foo" methodname
  .   .   ParameterDeclList [0]
  .   .   StmtList [3]
  .   .   . IfStmt
  .   .   .   RefExpr
  .   .   .     IdRef
  .   .   .       "b" Identifier
  .   .   .   IfStmt
  .   .   .     RefExpr
  .   .   .       IdRef
  .   .   .         "c" Identifier
  .   .   .     AssignStmt
  .   .   .       IdRef
  .   .   .         "x" Identifier
  .   .   .       LiteralExpr
  .   .   .         "1" IntLiteral
  .   .   .     AssignStmt
  .   .   .       IdRef
  .   .   .         "x" Identifier
  .   .   .       LiteralExpr
  .   .   .         "2" IntLiteral
  .   .   .   IfStmt
  .   .   .     RefExpr
  .   .   .       IdRef
  .   .   .         "d" Identifier
  .   .   .     AssignStmt
  .   .   .       IdRef
  .   .   .         "x" Identifier
  .   .   .       LiteralExpr
  .   .   .         "11" IntLiteral
  .   .   .     AssignStmt
  .   .   .       IdRef
  .   .   .         "x" Identifier
  .   .   .       LiteralExpr
  .   .   .         "22" IntLiteral
  .   .   . IfStmt
  .   .   .   LiteralExpr
  .   .   .     "true" BooleanLiteral
  .   .   .   IfStmt
  .   .   .     LiteralExpr
  .   .   .       "false" BooleanLiteral
  .   .   .     AssignStmt
  .   .   .       IdRef
  .   .   .         "x" Identifier
  .   .   .       LiteralExpr
  .   .   .         "3" IntLiteral
  .   .   .     AssignStmt
  .   .   .       IdRef
  .   .   .         "x" Identifier
  .   .   .       LiteralExpr
  .   .   .         "4" IntLiteral
  .   .   . IfStmt
  .   .   .   UnaryExpr
  .   .   .     "!" Operator
  .   .   .       LiteralExpr
  .   .   .         "true" BooleanLiteral
  .   .   .   AssignStmt
  .   .   .     IdRef
  .   .   .       "x" Identifier
  .   .   .     LiteralExpr
  .   .   .       "33" IntLiteral
  .   .   .   IfStmt
  .   .   .     UnaryExpr
  .   .   .       "!" Operator
  .   .   .         LiteralExpr
  .   .   .           "false" BooleanLiteral
  .   .   .     AssignStmt
  .   .   .       IdRef
  .   .   .         "x" Identifier
  .   .   .       LiteralExpr
  .   .   .         "44" IntLiteral
  .   .   .     AssignStmt
  .   .   .       IdRef
  .   .   .         "x" Identifier
  .   .   .       LiteralExpr
  .   .   .         "55" IntLiteral
=============================================