class Prism::SingletonClassNode

Represents a singleton class declaration involving the ‘class` keyword.

class << self end
^^^^^^^^^^^^^^^^^

Attributes

body[R]

attr_reader body: Node?

class_keyword_loc[R]

attr_reader class_keyword_loc: Location

end_keyword_loc[R]

attr_reader end_keyword_loc: Location

expression[R]

attr_reader expression: Node

locals[R]

attr_reader locals: Array

operator_loc[R]

attr_reader operator_loc: Location

Public Class Methods

new(locals, class_keyword_loc, operator_loc, expression, body, end_keyword_loc, location) click to toggle source

def initialize: (locals: Array, class_keyword_loc: Location, operator_loc: Location, expression: Node, body: Node?, end_keyword_loc: Location, location: Location) -> void

# File lib/prism/node.rb, line 15302
def initialize(locals, class_keyword_loc, operator_loc, expression, body, end_keyword_loc, location)
  @locals = locals
  @class_keyword_loc = class_keyword_loc
  @operator_loc = operator_loc
  @expression = expression
  @body = body
  @end_keyword_loc = end_keyword_loc
  @location = location
end

type() click to toggle source

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 lib/prism/node.rb, line 15413
def self.type
  :singleton_class_node
end

Public Instance Methods

accept(visitor) click to toggle source

def accept: (visitor: Visitor) -> void

# File lib/prism/node.rb, line 15313
def accept(visitor)
  visitor.visit_singleton_class_node(self)
end

child_nodes() click to toggle source

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

# File lib/prism/node.rb, line 15318
def child_nodes
  [expression, body]
end

Also aliased as: deconstruct

class_keyword() click to toggle source

def class_keyword: () -> String

# File lib/prism/node.rb, line 15357
def class_keyword
  class_keyword_loc.slice
end

comment_targets() click to toggle source

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

# File lib/prism/node.rb, line 15331
def comment_targets
  [class_keyword_loc, operator_loc, expression, *body, end_keyword_loc]
end

compact_child_nodes() click to toggle source

def compact_child_nodes: () -> Array

# File lib/prism/node.rb, line 15323
def compact_child_nodes
  compact = []
  compact << expression
  compact << body if body
  compact
end

copy(**params) click to toggle source

def copy: (**params) -> SingletonClassNode

# File lib/prism/node.rb, line 15336
def copy(**params)
  SingletonClassNode.new(
    params.fetch(:locals) { locals },
    params.fetch(:class_keyword_loc) { class_keyword_loc },
    params.fetch(:operator_loc) { operator_loc },
    params.fetch(:expression) { expression },
    params.fetch(:body) { body },
    params.fetch(:end_keyword_loc) { end_keyword_loc },
    params.fetch(:location) { location },
  )
end

deconstruct()

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

Alias for: child_nodes

deconstruct_keys(keys) click to toggle source

# File lib/prism/node.rb, line 15352
def deconstruct_keys(keys)
  { locals: locals, class_keyword_loc: class_keyword_loc, operator_loc: operator_loc, expression: expression, body: body, end_keyword_loc: end_keyword_loc, location: location }
end

end_keyword() click to toggle source

def end_keyword: () -> String

# File lib/prism/node.rb, line 15367
def end_keyword
  end_keyword_loc.slice
end

inspect(inspector = NodeInspector.new) click to toggle source

def inspect(inspector: NodeInspector) -> String

# File lib/prism/node.rb, line 15372
def inspect(inspector = NodeInspector.new)
  inspector << inspector.header(self)
  inspector << "├── locals: #{locals.inspect}\n"
  inspector << "├── class_keyword_loc: #{inspector.location(class_keyword_loc)}\n"
  inspector << "├── operator_loc: #{inspector.location(operator_loc)}\n"
  inspector << "├── expression:\n"
  inspector << inspector.child_node(expression, "│   ")
  if (body = self.body).nil?
    inspector << "├── body: ∅\n"
  else
    inspector << "├── body:\n"
    inspector << body.inspect(inspector.child_inspector("│   ")).delete_prefix(inspector.prefix)
  end
  inspector << "└── end_keyword_loc: #{inspector.location(end_keyword_loc)}\n"
  inspector.to_str
end

operator() click to toggle source

def operator: () -> String

# File lib/prism/node.rb, line 15362
def operator
  operator_loc.slice
end

type() click to toggle source

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 lib/prism/node.rb, line 15403
def type
  :singleton_class_node
end