class Prism::CapturePatternNode

Represents assigning to a local variable in pattern matching.

foo => [bar => baz]



attr_reader target: Prism::node


attr_reader value: Prism::node

Public Class Methods

new(source, value, target, operator_loc, location) click to toggle source

def initialize: (Prism::node value, Prism::node target, Location operator_loc, Location location) -> void

# File lib/prism/node.rb, line 3215
def initialize(source, value, target, operator_loc, location)
  @source = source
  @location = location
  @value = value
  @target = target
  @operator_loc = operator_loc
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 3303
def self.type

Public Instance Methods

===(other) click to toggle source

Implements case-equality for the node. This is effectively == but without comparing the value of locations. Locations are checked only for presence.

# File lib/prism/node.rb, line 3309
def ===(other)
  other.is_a?(CapturePatternNode) &&
    (value === other.value) &&
    (target === &&
    (operator_loc.nil? == other.operator_loc.nil?)
accept(visitor) click to toggle source

def accept: (Visitor visitor) -> void

# File lib/prism/node.rb, line 3224
def accept(visitor)
child_nodes() click to toggle source

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

# File lib/prism/node.rb, line 3229
def child_nodes
  [value, target]
Also aliased as: deconstruct
comment_targets() click to toggle source

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

# File lib/prism/node.rb, line 3239
def comment_targets
  [value, target, operator_loc] #: Array[Prism::node | Location]
compact_child_nodes() click to toggle source

def compact_child_nodes: () -> Array

# File lib/prism/node.rb, line 3234
def compact_child_nodes
  [value, target]
copy(value: self.value, target:, operator_loc: self.operator_loc, location: self.location) click to toggle source

def copy: (?value: Prism::node, ?target: Prism::node, ?operator_loc: Location, ?location: Location) -> CapturePatternNode

# File lib/prism/node.rb, line 3244
def copy(value: self.value, target:, operator_loc: self.operator_loc, location: self.location), value, target, operator_loc, location)

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

Alias for: child_nodes
deconstruct_keys(keys) click to toggle source

def deconstruct_keys: (Array keys) -> { value: Prism::node, target: Prism::node, operator_loc: Location, location: Location }

# File lib/prism/node.rb, line 3252
def deconstruct_keys(keys)
  { value: value, target: target, operator_loc: operator_loc, location: location }
inspect() click to toggle source

def inspect -> String

# File lib/prism/node.rb, line 3275
def inspect
operator() click to toggle source

def operator: () -> String

# File lib/prism/node.rb, line 3270
def operator
operator_loc() click to toggle source

attr_reader operator_loc: Location

# File lib/prism/node.rb, line 3263
def operator_loc
  location = @operator_loc
  return location if location.is_a?(Location)
  @operator_loc =, location >> 32, location & 0xFFFFFFFF)
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 3293
def type