Represents an array pattern in pattern matching.

foo in 1, 2
^^^^^^^^^^^

foo in [1, 2]
^^^^^^^^^^^^^

foo in *1
^^^^^^^^^

foo in Bar[]
^^^^^^^^^^^^

foo in Bar[1, 2, 3]
^^^^^^^^^^^^^^^^^^^
Attributes
Read

attr_reader constant: Node?

Read

attr_reader requireds: Array

Read

attr_reader rest: Node?

Read

attr_reader posts: Array

attr_reader opening_loc: Location?

attr_reader closing_loc: Location?

Class Methods

def initialize: (constant: Node?, requireds: Array, rest: Node?, posts: Array, opening_loc: Location?, closing_loc: Location?, location: Location) -> void

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

Instance Methods

def accept: (visitor: Visitor) -> void

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

def closing: () -> String?

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

def copy: (**params) -> ArrayPatternNode

An alias for child_nodes

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

def inspect(inspector: NodeInspector) -> String

def opening: () -> String?

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