Represents reading a local variable. Note that this requires that a local variable of the same name has already been written to in the same scope, otherwise it is parsed as a method call.
foo ^^^
The name of the local variable, which is an [identifier](github.com/ruby/prism/blob/main/docs/parsing_rules.md#identifiers).
x # name `:x` _Test # name `:_Test`
Note that this can also be an underscore followed by a number for the default block parameters.
_1 # name `:_1`
Finally, for the default ‘it` block parameter, the name is `0it`. This is to distinguish it from an `it` local variable that is explicitly declared.
it # name `:0it`
The number of visible scopes that should be searched to find the origin of this local variable.
foo = 1; foo # depth 0 bar = 2; tap { bar } # depth 1
The specific rules for calculating the depth may differ from individual Ruby implementations, as they are not specified by the language. For more information, see [the Prism documentation](github.com/ruby/prism/blob/main/docs/local_variable_depth.md).
# File tmp/rubies/ruby-3.4.0-preview1/lib/prism/node.rb, line 12204
def initialize(source, name, depth, location)
@source = source
@location = location
@name = name
@depth = depth
end
# File tmp/rubies/ruby-3.4.0-preview1/lib/prism/node.rb, line 12297
def self.type
:local_variable_read_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 12303
def ===(other)
other.is_a?(LocalVariableReadNode) &&
(name === other.name) &&
(depth === other.depth)
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 12212
def accept(visitor)
visitor.visit_local_variable_read_node(self)
end
def accept: (Visitor visitor) -> void
# File tmp/rubies/ruby-3.4.0-preview1/lib/prism/node.rb, line 12217
def child_nodes
[]
end
def child_nodes: () -> Array[nil | Node]
# File tmp/rubies/ruby-3.4.0-preview1/lib/prism/node.rb, line 12227
def comment_targets
[] #: Array[Prism::node | Location]
end
def comment_targets: () -> Array[Node | Location]
# File tmp/rubies/ruby-3.4.0-preview1/lib/prism/node.rb, line 12222
def compact_child_nodes
[]
end
def compact_child_nodes: () -> Array
# File tmp/rubies/ruby-3.4.0-preview1/lib/prism/node.rb, line 12232
def copy(name: self.name, depth: self.depth, location: self.location)
LocalVariableReadNode.new(source, name, depth, location)
end
def copy: (?name: Symbol, ?depth: Integer, ?location: Location) -> LocalVariableReadNode
# File tmp/rubies/ruby-3.4.0-preview1/lib/prism/node.rb, line 12240
def deconstruct_keys(keys)
{ name: name, depth: depth, location: location }
end
def deconstruct_keys: (Array keys) -> { name: Symbol, depth: Integer, location: Location }
# File tmp/rubies/ruby-3.4.0-preview1/lib/prism/node.rb, line 12269
def inspect
InspectVisitor.compose(self)
end
def inspect -> String
# File tmp/rubies/ruby-3.4.0-preview1/lib/prism/node.rb, line 12287
def type
:local_variable_read_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