Represents the use of the ‘when` keyword within a case statement.
case true when true ^^^^^^^^^ end
attr_reader conditions: Array
attr_reader statements: StatementsNode?
# File tmp/rubies/ruby-3.4.0-preview1/lib/prism/node.rb, line 18423
def initialize(source, keyword_loc, conditions, then_keyword_loc, statements, location)
@source = source
@location = location
@keyword_loc = keyword_loc
@conditions = conditions
@then_keyword_loc = then_keyword_loc
@statements = statements
end
def initialize: (Location keyword_loc, Array conditions, Location? then_keyword_loc, StatementsNode? statements, Location location) -> void
# File tmp/rubies/ruby-3.4.0-preview1/lib/prism/node.rb, line 18533
def self.type
:when_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 18539
def ===(other)
other.is_a?(WhenNode) &&
(keyword_loc.nil? == other.keyword_loc.nil?) &&
(conditions.length == other.conditions.length) &&
conditions.zip(other.conditions).all? { |left, right| left === right } &&
(then_keyword_loc.nil? == other.then_keyword_loc.nil?) &&
(statements === other.statements)
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 18433
def accept(visitor)
visitor.visit_when_node(self)
end
def accept: (Visitor visitor) -> void
# File tmp/rubies/ruby-3.4.0-preview1/lib/prism/node.rb, line 18438
def child_nodes
[*conditions, statements]
end
def child_nodes: () -> Array[nil | Node]
# File tmp/rubies/ruby-3.4.0-preview1/lib/prism/node.rb, line 18451
def comment_targets
[keyword_loc, *conditions, *then_keyword_loc, *statements] #: Array[Prism::node | Location]
end
def comment_targets: () -> Array[Node | Location]
# File tmp/rubies/ruby-3.4.0-preview1/lib/prism/node.rb, line 18443
def compact_child_nodes
compact = [] #: Array[Prism::node]
compact.concat(conditions)
compact << statements if statements
compact
end
def compact_child_nodes: () -> Array
# File tmp/rubies/ruby-3.4.0-preview1/lib/prism/node.rb, line 18456
def copy(keyword_loc: self.keyword_loc, conditions: self.conditions, then_keyword_loc: self.then_keyword_loc, statements: self.statements, location: self.location)
WhenNode.new(source, keyword_loc, conditions, then_keyword_loc, statements, location)
end
# File tmp/rubies/ruby-3.4.0-preview1/lib/prism/node.rb, line 18464
def deconstruct_keys(keys)
{ keyword_loc: keyword_loc, conditions: conditions, then_keyword_loc: then_keyword_loc, statements: statements, location: location }
end
def deconstruct_keys: (Array keys) -> { keyword_loc: Location, conditions: Array, then_keyword_loc: Location?, statements: StatementsNode?, location: Location }
# File tmp/rubies/ruby-3.4.0-preview1/lib/prism/node.rb, line 18505
def inspect
InspectVisitor.compose(self)
end
def inspect -> String
# File tmp/rubies/ruby-3.4.0-preview1/lib/prism/node.rb, line 18495
def keyword
keyword_loc.slice
end
def keyword: () -> String
# File tmp/rubies/ruby-3.4.0-preview1/lib/prism/node.rb, line 18469
def keyword_loc
location = @keyword_loc
return location if location.is_a?(Location)
@keyword_loc = Location.new(source, location >> 32, location & 0xFFFFFFFF)
end
attr_reader keyword_loc: Location
# File tmp/rubies/ruby-3.4.0-preview1/lib/prism/node.rb, line 18500
def then_keyword
then_keyword_loc&.slice
end
def then_keyword: () -> String?
# File tmp/rubies/ruby-3.4.0-preview1/lib/prism/node.rb, line 18479
def then_keyword_loc
location = @then_keyword_loc
case location
when nil
nil
when Location
location
else
@then_keyword_loc = Location.new(source, location >> 32, location & 0xFFFFFFFF)
end
end
attr_reader then_keyword_loc: Location?
# File tmp/rubies/ruby-3.4.0-preview1/lib/prism/node.rb, line 18523
def type
:when_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