class Prism::LocalVariableReadNode

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
^^^

Attributes

depth[R]

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).

name[R]

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`

Public Class Methods

new(source, name, depth, location) click to toggle source

def initialize: (Symbol name, Integer depth, Location location) -> void

# File lib/prism/node.rb, line 12280
def initialize(source, name, depth, location)
  @source = source
  @newline = false
  @location = location
  @name = name
  @depth = depth
end

type() click to toggle source

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 lib/prism/node.rb, line 12374
def self.type
  :local_variable_read_node
end

Public Instance Methods

===(other) click to toggle source

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

# File lib/prism/node.rb, line 12380
def ===(other)
  other.is_a?(LocalVariableReadNode) &&
    (name === other.name) &&
    (depth === other.depth)
end

accept(visitor) click to toggle source

def accept: (Visitor visitor) -> void

# File lib/prism/node.rb, line 12289
def accept(visitor)
  visitor.visit_local_variable_read_node(self)
end

child_nodes() click to toggle source

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

# File lib/prism/node.rb, line 12294
def child_nodes
  []
end

Also aliased as: deconstruct

comment_targets() click to toggle source

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

# File lib/prism/node.rb, line 12304
def comment_targets
  [] #: Array[Prism::node | Location]
end

compact_child_nodes() click to toggle source

def compact_child_nodes: () -> Array

# File lib/prism/node.rb, line 12299
def compact_child_nodes
  []
end

copy(name: self.name, depth: self.depth, location: self.location) click to toggle source

def copy: (?name: Symbol, ?depth: Integer, ?location: Location) -> LocalVariableReadNode

# File lib/prism/node.rb, line 12309
def copy(name: self.name, depth: self.depth, location: self.location)
  LocalVariableReadNode.new(source, name, depth, location)
end

deconstruct()

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

Alias for: child_nodes

deconstruct_keys(keys) click to toggle source

def deconstruct_keys: (Array keys) -> { name: Symbol, depth: Integer, location: Location }

# File lib/prism/node.rb, line 12317
def deconstruct_keys(keys)
  { name: name, depth: depth, location: location }
end

inspect() click to toggle source

def inspect -> String

# File lib/prism/node.rb, line 12346
def inspect
  InspectVisitor.compose(self)
end

type() click to toggle source

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 lib/prism/node.rb, line 12364
def type
  :local_variable_read_node
end