Represents the use of the ‘when` keyword within a case statement.
case true when true ^^^^^^^^^ end
attr_reader keyword_loc: Location
attr_reader conditions: Array
attr_reader statements: StatementsNode?
# File tmp/rubies/ruby-3.3.0/lib/prism/node.rb, line 16776
def initialize(keyword_loc, conditions, statements, location)
@keyword_loc = keyword_loc
@conditions = conditions
@statements = statements
@location = location
end
def initialize: (keyword_loc: Location, conditions: Array, statements: StatementsNode?, location: Location) -> void
# File tmp/rubies/ruby-3.3.0/lib/prism/node.rb, line 16867
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-3.3.0/lib/prism/node.rb, line 16784
def accept(visitor)
visitor.visit_when_node(self)
end
def accept: (visitor: Visitor) -> void
# File tmp/rubies/ruby-3.3.0/lib/prism/node.rb, line 16789
def child_nodes
[*conditions, statements]
end
def child_nodes: () -> Array[nil | Node]
# File tmp/rubies/ruby-3.3.0/lib/prism/node.rb, line 16802
def comment_targets
[keyword_loc, *conditions, *statements]
end
def comment_targets: () -> Array[Node | Location]
# File tmp/rubies/ruby-3.3.0/lib/prism/node.rb, line 16794
def compact_child_nodes
compact = []
compact.concat(conditions)
compact << statements if statements
compact
end
def compact_child_nodes: () -> Array
# File tmp/rubies/ruby-3.3.0/lib/prism/node.rb, line 16807
def copy(**params)
WhenNode.new(
params.fetch(:keyword_loc) { keyword_loc },
params.fetch(:conditions) { conditions },
params.fetch(:statements) { statements },
params.fetch(:location) { location },
)
end
def copy: (**params) -> WhenNode
# File tmp/rubies/ruby-3.3.0/lib/prism/node.rb, line 16820
def deconstruct_keys(keys)
{ keyword_loc: keyword_loc, conditions: conditions, statements: statements, location: location }
end
# File tmp/rubies/ruby-3.3.0/lib/prism/node.rb, line 16830
def inspect(inspector = NodeInspector.new)
inspector << inspector.header(self)
inspector << "├── keyword_loc: #{inspector.location(keyword_loc)}\n"
inspector << "├── conditions: #{inspector.list("#{inspector.prefix}│ ", conditions)}"
if (statements = self.statements).nil?
inspector << "└── statements: ∅\n"
else
inspector << "└── statements:\n"
inspector << statements.inspect(inspector.child_inspector(" ")).delete_prefix(inspector.prefix)
end
inspector.to_str
end
def inspect(inspector: NodeInspector) -> String
# File tmp/rubies/ruby-3.3.0/lib/prism/node.rb, line 16825
def keyword
keyword_loc.slice
end
def keyword: () -> String
# File tmp/rubies/ruby-3.3.0/lib/prism/node.rb, line 16857
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