class Prism::AlternationPatternNode

Represents an alternation pattern in pattern matching.

foo => bar | baz



attr_reader left: Node


attr_reader operator_loc: Location


attr_reader right: Node

Public Class Methods

new(left, right, operator_loc, location) click to toggle source

def initialize: (left: Node, right: Node, operator_loc: Location, location: Location) -> void

# File prism/node.rb, line 273
def initialize(left, right, operator_loc, location)
  @left = left
  @right = right
  @operator_loc = operator_loc
  @location = location
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 prism/node.rb, line 358
def self.type

Public Instance Methods

accept(visitor) click to toggle source

def accept: (visitor: Visitor) -> void

# File prism/node.rb, line 281
def accept(visitor)
child_nodes() click to toggle source

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

# File prism/node.rb, line 286
def child_nodes
  [left, right]
Also aliased as: deconstruct
comment_targets() click to toggle source

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

# File prism/node.rb, line 296
def comment_targets
  [left, right, operator_loc]
compact_child_nodes() click to toggle source

def compact_child_nodes: () -> Array

# File prism/node.rb, line 291
def compact_child_nodes
  [left, right]
copy(**params) click to toggle source

def copy: (**params) -> AlternationPatternNode

# File prism/node.rb, line 301
def copy(**params)
    params.fetch(:left) { left },
    params.fetch(:right) { right },
    params.fetch(:operator_loc) { operator_loc },
    params.fetch(:location) { location },

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

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

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

# File prism/node.rb, line 314
def deconstruct_keys(keys)
  { left: left, right: right, operator_loc: operator_loc, location: location }
inspect(inspector = click to toggle source

def inspect(inspector: NodeInspector) -> String

# File prism/node.rb, line 324
def inspect(inspector =
  inspector << inspector.header(self)
  inspector << "├── left:\n"
  inspector << inspector.child_node(left, "│   ")
  inspector << "├── right:\n"
  inspector << inspector.child_node(right, "│   ")
  inspector << "└── operator_loc: #{inspector.location(operator_loc)}\n"
operator() click to toggle source

def operator: () -> String

# File prism/node.rb, line 319
def operator
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 prism/node.rb, line 348
def type