class Prism::UndefNode

def initialize: (names: Array, keyword_loc: Location, location: Location) -> void

# File prism/node.rb, line 16379
def initialize(names, keyword_loc, location)
  @names = names
  @keyword_loc = keyword_loc
  @location = location
end

Similar to type, this method returns a symbol that you can use for splitting on the type of the node without having to do a long === chain. Note that like type, it will still be slower than using == for a single class, but should be faster in a case statement or an array comparison.

def self.type: () -> Symbol

# File prism/node.rb, line 16459
def self.type
  :undef_node
end

def accept: (visitor: Visitor) -> void

# File prism/node.rb, line 16386
def accept(visitor)
  visitor.visit_undef_node(self)
end

def child_nodes: () -> Array[nil | Node]

# File prism/node.rb, line 16391
def child_nodes
  [*names]
end

def comment_targets: () -> Array[Node | Location]

# File prism/node.rb, line 16401
def comment_targets
  [*names, keyword_loc]
end

def compact_child_nodes: () -> Array

# File prism/node.rb, line 16396
def compact_child_nodes
  [*names]
end

def copy: (**params) -> UndefNode

# File prism/node.rb, line 16406
def copy(**params)
  UndefNode.new(
    params.fetch(:names) { names },
    params.fetch(:keyword_loc) { keyword_loc },
    params.fetch(:location) { location },
  )
end

def deconstruct_keys: (keys: Array) -> Hash[Symbol, nil | Node | Array | String | Token | Array | Location]

# File prism/node.rb, line 16418
def deconstruct_keys(keys)
  { names: names, keyword_loc: keyword_loc, location: location }
end

def inspect(inspector: NodeInspector) -> String

# File prism/node.rb, line 16428
def inspect(inspector = NodeInspector.new)
  inspector << inspector.header(self)
  inspector << "├── names: #{inspector.list("#{inspector.prefix}│   ", names)}"
  inspector << "└── keyword_loc: #{inspector.location(keyword_loc)}\n"
  inspector.to_str
end

def keyword: () -> String

# File prism/node.rb, line 16423
def keyword
  keyword_loc.slice
end

Sometimes you want to check an instance of a node against a list of classes to see what kind of behavior to perform. Usually this is done by calling ‘[cls1, cls2].include?(node.class)` or putting the node into a case statement and doing `case node; when cls1; when cls2; end`. Both of these approaches are relatively slow because of the constant lookups, method calls, and/or array allocations.

Instead, you can call type, which will return to you a symbol that you can use for comparison. This is faster than the other approaches because it uses a single integer comparison, but also because if you’re on CRuby you can take advantage of the fact that case statements with all symbol keys will use a jump table.

def type: () -> Symbol

# File prism/node.rb, line 16449
def type
  :undef_node
end