Represents the use of the ‘when` keyword within a case statement.

case true
when true
^^^^^^^^^
end
Attributes
Read

attr_reader conditions: Array

Read

attr_reader statements: StatementsNode?

Class Methods

def initialize: (Location keyword_loc, Array conditions, Location? then_keyword_loc, StatementsNode? statements, 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

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

def accept: (Visitor visitor) -> void

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

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

def copy: (?keyword_loc: Location, ?conditions: Array, ?then_keyword_loc: Location?, ?statements: StatementsNode?, ?location: Location) -> WhenNode

An alias for child_nodes

def deconstruct_keys: (Array keys) -> { keyword_loc: Location, conditions: Array, then_keyword_loc: Location?, statements: StatementsNode?, location: Location }

def inspect -> String

def keyword: () -> String

attr_reader keyword_loc: Location

def then_keyword: () -> String?

attr_reader then_keyword_loc: Location?

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