class Prism::ParametersNode

Represents the list of parameters on a method, block, or lambda definition.

def a(b, c, d)
      ^^^^^^^
end

Attributes

block[R]

attr_reader block: BlockParameterNode?

keyword_rest[R]

attr_reader keyword_rest: Node?

keywords[R]

attr_reader keywords: Array

optionals[R]

attr_reader optionals: Array

posts[R]

attr_reader posts: Array

requireds[R]

attr_reader requireds: Array

rest[R]

attr_reader rest: Node?

Public Class Methods

new(requireds, optionals, rest, posts, keywords, keyword_rest, block, location) click to toggle source

def initialize: (requireds: Array, optionals: Array, rest: Node?, posts: Array, keywords: Array, keyword_rest: Node?, block: BlockParameterNode?, location: Location) -> void

# File lib/prism/node.rb, line 13187
def initialize(requireds, optionals, rest, posts, keywords, keyword_rest, block, location)
  @requireds = requireds
  @optionals = optionals
  @rest = rest
  @posts = posts
  @keywords = keywords
  @keyword_rest = keyword_rest
  @block = block
  @location = location
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 13300
def self.type
  :parameters_node
end

Public Instance Methods

accept(visitor) click to toggle source

def accept: (visitor: Visitor) -> void

# File lib/prism/node.rb, line 13199
def accept(visitor)
  visitor.visit_parameters_node(self)
end

child_nodes() click to toggle source

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

# File lib/prism/node.rb, line 13204
def child_nodes
  [*requireds, *optionals, rest, *posts, *keywords, keyword_rest, block]
end

Also aliased as: deconstruct

comment_targets() click to toggle source

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

# File lib/prism/node.rb, line 13222
def comment_targets
  [*requireds, *optionals, *rest, *posts, *keywords, *keyword_rest, *block]
end

compact_child_nodes() click to toggle source

def compact_child_nodes: () -> Array

# File lib/prism/node.rb, line 13209
def compact_child_nodes
  compact = []
  compact.concat(requireds)
  compact.concat(optionals)
  compact << rest if rest
  compact.concat(posts)
  compact.concat(keywords)
  compact << keyword_rest if keyword_rest
  compact << block if block
  compact
end

copy(**params) click to toggle source

def copy: (**params) -> ParametersNode

# File lib/prism/node.rb, line 13227
def copy(**params)
  ParametersNode.new(
    params.fetch(:requireds) { requireds },
    params.fetch(:optionals) { optionals },
    params.fetch(:rest) { rest },
    params.fetch(:posts) { posts },
    params.fetch(:keywords) { keywords },
    params.fetch(:keyword_rest) { keyword_rest },
    params.fetch(:block) { block },
    params.fetch(:location) { location },
  )
end

deconstruct()

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

Alias for: child_nodes

deconstruct_keys(keys) click to toggle source

# File lib/prism/node.rb, line 13244
def deconstruct_keys(keys)
  { requireds: requireds, optionals: optionals, rest: rest, posts: posts, keywords: keywords, keyword_rest: keyword_rest, block: block, location: location }
end

inspect(inspector = NodeInspector.new) click to toggle source

def inspect(inspector: NodeInspector) -> String

# File lib/prism/node.rb, line 13249
def inspect(inspector = NodeInspector.new)
  inspector << inspector.header(self)
  inspector << "├── requireds: #{inspector.list("#{inspector.prefix}│   ", requireds)}"
  inspector << "├── optionals: #{inspector.list("#{inspector.prefix}│   ", optionals)}"
  if (rest = self.rest).nil?
    inspector << "├── rest: ∅\n"
  else
    inspector << "├── rest:\n"
    inspector << rest.inspect(inspector.child_inspector("│   ")).delete_prefix(inspector.prefix)
  end
  inspector << "├── posts: #{inspector.list("#{inspector.prefix}│   ", posts)}"
  inspector << "├── keywords: #{inspector.list("#{inspector.prefix}│   ", keywords)}"
  if (keyword_rest = self.keyword_rest).nil?
    inspector << "├── keyword_rest: ∅\n"
  else
    inspector << "├── keyword_rest:\n"
    inspector << keyword_rest.inspect(inspector.child_inspector("│   ")).delete_prefix(inspector.prefix)
  end
  if (block = self.block).nil?
    inspector << "└── block: ∅\n"
  else
    inspector << "└── block:\n"
    inspector << block.inspect(inspector.child_inspector("    ")).delete_prefix(inspector.prefix)
  end
  inspector.to_str
end

signature() click to toggle source

Mirrors the Method#parameters method.

# File lib/prism/node_ext.rb, line 149
def signature
  names = []

  requireds.each do |param|
    names << (param.is_a?(MultiTargetNode) ? [:req] : [:req, param.name])
  end

  optionals.each { |param| names << [:opt, param.name] }
  names << [:rest, rest.name || :*] if rest

  posts.each do |param|
    names << (param.is_a?(MultiTargetNode) ? [:req] : [:req, param.name])
  end

  # Regardless of the order in which the keywords were defined, the required
  # keywords always come first followed by the optional keywords.
  keyopt = []
  keywords.each do |param|
    if param.is_a?(OptionalKeywordParameterNode)
      keyopt << param
    else
      names << [:keyreq, param.name]
    end
  end

  keyopt.each { |param| names << [:key, param.name] }

  case keyword_rest
  when ForwardingParameterNode
    names.concat([[:rest, :*], [:keyrest, :**], [:block, :&]])
  when KeywordRestParameterNode
    names << [:keyrest, keyword_rest.name || :**]
  when NoKeywordsParameterNode
    names << [:nokey]
  end

  names << [:block, block.name || :&] if block
  names
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 13290
def type
  :parameters_node
end