class Prism::IfNode

Represents the use of the ‘if` keyword, either in the block form or the modifier form, or a ternary expression.

bar if foo
^^^^^^^^^^

if foo then bar end
^^^^^^^^^^^^^^^^^^^

foo ? bar : baz
^^^^^^^^^^^^^^^

Attributes

consequent[R]

Represents an ‘ElseNode` or an `IfNode` when there is an `else` or an `elsif` in the `if` statement.

if foo
  bar
elsif baz
^^^^^^^^^
  qux
  ^^^
end
^^^

if foo then bar else baz end
                ^^^^^^^^^^^^

predicate[R]

The node for the condition the ‘IfNode` is testing.

if foo
   ^^^
  bar
end

bar if foo
       ^^^

foo ? bar : baz
^^^

statements[R]

Represents the body of statements that will be executed when the predicate is evaluated as truthy. Will be ‘nil` when no body is provided.

if foo
  bar
  ^^^
  baz
  ^^^
end

Public Class Methods

new(source, if_keyword_loc, predicate, then_keyword_loc, statements, consequent, end_keyword_loc, location) click to toggle source

def initialize: (Location? if_keyword_loc, Prism::node predicate, Location? then_keyword_loc, StatementsNode? statements, Prism::node? consequent, Location? end_keyword_loc, Location location) -> void

# File lib/prism/node.rb, line 8491
def initialize(source, if_keyword_loc, predicate, then_keyword_loc, statements, consequent, end_keyword_loc, location)
  @source = source
  @newline = false
  @location = location
  @if_keyword_loc = if_keyword_loc
  @predicate = predicate
  @then_keyword_loc = then_keyword_loc
  @statements = statements
  @consequent = consequent
  @end_keyword_loc = end_keyword_loc
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 8682
def self.type
  :if_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 8688
def ===(other)
  other.is_a?(IfNode) &&
    (if_keyword_loc.nil? == other.if_keyword_loc.nil?) &&
    (predicate === other.predicate) &&
    (then_keyword_loc.nil? == other.then_keyword_loc.nil?) &&
    (statements === other.statements) &&
    (consequent === other.consequent) &&
    (end_keyword_loc.nil? == other.end_keyword_loc.nil?)
end

accept(visitor) click to toggle source

def accept: (Visitor visitor) -> void

# File lib/prism/node.rb, line 8504
def accept(visitor)
  visitor.visit_if_node(self)
end

child_nodes() click to toggle source

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

# File lib/prism/node.rb, line 8513
def child_nodes
  [predicate, statements, consequent]
end

Also aliased as: deconstruct

comment_targets() click to toggle source

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

# File lib/prism/node.rb, line 8527
def comment_targets
  [*if_keyword_loc, predicate, *then_keyword_loc, *statements, *consequent, *end_keyword_loc] #: Array[Prism::node | Location]
end

compact_child_nodes() click to toggle source

def compact_child_nodes: () -> Array

# File lib/prism/node.rb, line 8518
def compact_child_nodes
  compact = [] #: Array[Prism::node]
  compact << predicate
  compact << statements if statements
  compact << consequent if consequent
  compact
end

copy(if_keyword_loc: self.if_keyword_loc, predicate: self.predicate, then_keyword_loc: self.then_keyword_loc, statements: self.statements, consequent: self.consequent, end_keyword_loc: self.end_keyword_loc, location: self.location) click to toggle source

def copy: (?if_keyword_loc: Location?, ?predicate: Prism::node, ?then_keyword_loc: Location?, ?statements: StatementsNode?, ?consequent: Prism::node?, ?end_keyword_loc: Location?, ?location: Location) -> IfNode

# File lib/prism/node.rb, line 8532
def copy(if_keyword_loc: self.if_keyword_loc, predicate: self.predicate, then_keyword_loc: self.then_keyword_loc, statements: self.statements, consequent: self.consequent, end_keyword_loc: self.end_keyword_loc, location: self.location)
  IfNode.new(source, if_keyword_loc, predicate, then_keyword_loc, statements, consequent, end_keyword_loc, location)
end

deconstruct()

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

Alias for: child_nodes

deconstruct_keys(keys) click to toggle source

def deconstruct_keys: (Array keys) -> { if_keyword_loc: Location?, predicate: Prism::node, then_keyword_loc: Location?, statements: StatementsNode?, consequent: Prism::node?, end_keyword_loc: Location?, location: Location }

# File lib/prism/node.rb, line 8540
def deconstruct_keys(keys)
  { if_keyword_loc: if_keyword_loc, predicate: predicate, then_keyword_loc: then_keyword_loc, statements: statements, consequent: consequent, end_keyword_loc: end_keyword_loc, location: location }
end

end_keyword() click to toggle source

def end_keyword: () -> String?

# File lib/prism/node.rb, line 8649
def end_keyword
  end_keyword_loc&.slice
end

end_keyword_loc() click to toggle source

The location of the ‘end` keyword if present, `nil` otherwise.

if foo
  bar
end
^^^

# File lib/prism/node.rb, line 8626
def end_keyword_loc
  location = @end_keyword_loc
  case location
  when nil
    nil
  when Location
    location
  else
    @end_keyword_loc = Location.new(source, location >> 32, location & 0xFFFFFFFF)
  end
end

if_keyword() click to toggle source

def if_keyword: () -> String?

# File lib/prism/node.rb, line 8639
def if_keyword
  if_keyword_loc&.slice
end

if_keyword_loc() click to toggle source

The location of the ‘if` keyword if present.

bar if foo
    ^^

The ‘if_keyword_loc` field will be `nil` when the `IfNode` represents a ternary expression.

# File lib/prism/node.rb, line 8550
def if_keyword_loc
  location = @if_keyword_loc
  case location
  when nil
    nil
  when Location
    location
  else
    @if_keyword_loc = Location.new(source, location >> 32, location & 0xFFFFFFFF)
  end
end

inspect() click to toggle source

def inspect -> String

# File lib/prism/node.rb, line 8654
def inspect
  InspectVisitor.compose(self)
end

then_keyword() click to toggle source

def then_keyword: () -> String?

# File lib/prism/node.rb, line 8644
def then_keyword
  then_keyword_loc&.slice
end

then_keyword_loc() click to toggle source

The location of the ‘then` keyword (if present) or the `?` in a ternary expression, `nil` otherwise.

if foo then bar end
       ^^^^

a ? b : c
  ^

# File lib/prism/node.rb, line 8583
def then_keyword_loc
  location = @then_keyword_loc
  case location
  when nil
    nil
  when Location
    location
  else
    @then_keyword_loc = Location.new(source, location >> 32, location & 0xFFFFFFFF)
  end
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 8672
def type
  :if_node
end