class Prism::CaseNode
Represents the use of a case statement.
case true when false end ^^^^^^^^^^
Attributes
attr_reader case_keyword_loc
: Location
attr_reader conditions: Array
attr_reader consequent: ElseNode
?
attr_reader end_keyword_loc
: Location
attr_reader predicate: Node
?
Public Class Methods
def initialize: (predicate: Node
?, conditions: Array, consequent: ElseNode
?, case_keyword_loc
: Location
, end_keyword_loc
: Location
, location: Location
) -> void
# File prism/node.rb, line 3084 def initialize(predicate, conditions, consequent, case_keyword_loc, end_keyword_loc, location) @predicate = predicate @conditions = conditions @consequent = consequent @case_keyword_loc = case_keyword_loc @end_keyword_loc = end_keyword_loc @location = location 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 prism/node.rb, line 3192 def self.type :case_node end
Public Instance Methods
def accept: (visitor: Visitor
) -> void
# File prism/node.rb, line 3094 def accept(visitor) visitor.visit_case_node(self) end
def case_keyword
: () -> String
# File prism/node.rb, line 3138 def case_keyword case_keyword_loc.slice end
def child_nodes
: () -> Array[nil | Node]
# File prism/node.rb, line 3099 def child_nodes [predicate, *conditions, consequent] end
def comment_targets
: () -> Array[Node | Location]
# File prism/node.rb, line 3113 def comment_targets [*predicate, *conditions, *consequent, case_keyword_loc, end_keyword_loc] end
def compact_child_nodes
: () -> Array
# File prism/node.rb, line 3104 def compact_child_nodes compact = [] compact << predicate if predicate compact.concat(conditions) compact << consequent if consequent compact end
def copy: (**params) -> CaseNode
# File prism/node.rb, line 3118 def copy(**params) CaseNode.new( params.fetch(:predicate) { predicate }, params.fetch(:conditions) { conditions }, params.fetch(:consequent) { consequent }, params.fetch(:case_keyword_loc) { case_keyword_loc }, params.fetch(:end_keyword_loc) { end_keyword_loc }, params.fetch(:location) { location }, ) end
def deconstruct_keys
: (keys: Array) -> Hash[Symbol, nil | Node
| Array | String | Token
| Array | Location]
# File prism/node.rb, line 3133 def deconstruct_keys(keys) { predicate: predicate, conditions: conditions, consequent: consequent, case_keyword_loc: case_keyword_loc, end_keyword_loc: end_keyword_loc, location: location } end
def end_keyword
: () -> String
# File prism/node.rb, line 3143 def end_keyword end_keyword_loc.slice end
def inspect(inspector: NodeInspector) -> String
# File prism/node.rb, line 3148 def inspect(inspector = NodeInspector.new) inspector << inspector.header(self) if (predicate = self.predicate).nil? inspector << "├── predicate: ∅\n" else inspector << "├── predicate:\n" inspector << predicate.inspect(inspector.child_inspector("│ ")).delete_prefix(inspector.prefix) end inspector << "├── conditions: #{inspector.list("#{inspector.prefix}│ ", conditions)}" if (consequent = self.consequent).nil? inspector << "├── consequent: ∅\n" else inspector << "├── consequent:\n" inspector << consequent.inspect(inspector.child_inspector("│ ")).delete_prefix(inspector.prefix) end inspector << "├── case_keyword_loc: #{inspector.location(case_keyword_loc)}\n" inspector << "└── end_keyword_loc: #{inspector.location(end_keyword_loc)}\n" inspector.to_str 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
# File prism/node.rb, line 3182 def type :case_node end