Represents reading a reference to a field in the previous match.
$' ^^
The name of the back-reference variable, including the leading ‘$`.
$& # name `:$&` $+ # name `:$+`
# File tmp/rubies/ruby-3.4.0-preview1/lib/prism/node.rb, line 1297
def initialize(source, name, location)
@source = source
@location = location
@name = name
end
# File tmp/rubies/ruby-3.4.0-preview1/lib/prism/node.rb, line 1372
def self.type
:back_reference_read_node
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 tmp/rubies/ruby-3.4.0-preview1/lib/prism/node.rb, line 1378
def ===(other)
other.is_a?(BackReferenceReadNode) &&
(name === other.name)
end
Implements case-equality for the node. This is effectively == but without comparing the value of locations. Locations are checked only for presence.
# File tmp/rubies/ruby-3.4.0-preview1/lib/prism/node.rb, line 1304
def accept(visitor)
visitor.visit_back_reference_read_node(self)
end
def accept: (Visitor visitor) -> void
# File tmp/rubies/ruby-3.4.0-preview1/lib/prism/node.rb, line 1309
def child_nodes
[]
end
def child_nodes: () -> Array[nil | Node]
# File tmp/rubies/ruby-3.4.0-preview1/lib/prism/node.rb, line 1319
def comment_targets
[] #: Array[Prism::node | Location]
end
def comment_targets: () -> Array[Node | Location]
# File tmp/rubies/ruby-3.4.0-preview1/lib/prism/node.rb, line 1314
def compact_child_nodes
[]
end
def compact_child_nodes: () -> Array
# File tmp/rubies/ruby-3.4.0-preview1/lib/prism/node.rb, line 1324
def copy(name: self.name, location: self.location)
BackReferenceReadNode.new(source, name, location)
end
def copy: (?name: Symbol, ?location: Location) -> BackReferenceReadNode
# File tmp/rubies/ruby-3.4.0-preview1/lib/prism/node.rb, line 1332
def deconstruct_keys(keys)
{ name: name, location: location }
end
def deconstruct_keys: (Array keys) -> { name: Symbol, location: Location }
# File tmp/rubies/ruby-3.4.0-preview1/lib/prism/node.rb, line 1344
def inspect
InspectVisitor.compose(self)
end
def inspect -> String
# File tmp/rubies/ruby-3.4.0-preview1/lib/prism/node.rb, line 1362
def type
:back_reference_read_node
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