class Prism::ProgramNode
The top level node of any parse tree.
Attributes
attr_reader locals: Array
attr_reader statements: StatementsNode
Public Class Methods
def initialize: (Array locals, StatementsNode
statements, Location
location) -> void
# File prism/node.rb, line 15189 def initialize(source, locals, statements, location) @source = source @location = location @locals = locals @statements = statements 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 15264 def self.type :program_node end
Public Instance Methods
Implements case-equality for the node. This is effectively == but without comparing the value of locations. Locations are checked only for presence.
# File prism/node.rb, line 15270 def ===(other) other.is_a?(ProgramNode) && (locals.length == other.locals.length) && locals.zip(other.locals).all? { |left, right| left === right } && (statements === other.statements) end
def accept: (Visitor
visitor) -> void
# File prism/node.rb, line 15197 def accept(visitor) visitor.visit_program_node(self) end
def child_nodes
: () -> Array[nil | Node]
# File prism/node.rb, line 15202 def child_nodes [statements] end
def comment_targets
: () -> Array[Node | Location]
# File prism/node.rb, line 15212 def comment_targets [statements] #: Array[Prism::node | Location] end
def compact_child_nodes
: () -> Array
# File prism/node.rb, line 15207 def compact_child_nodes [statements] end
def copy: (?locals: Array, ?statements: StatementsNode
, ?location: Location
) -> ProgramNode
# File prism/node.rb, line 15217 def copy(locals: self.locals, statements: self.statements, location: self.location) ProgramNode.new(source, locals, statements, location) end
def deconstruct_keys
: (Array keys) -> { locals: Array, statements: StatementsNode
, location: Location
}
# File prism/node.rb, line 15225 def deconstruct_keys(keys) { locals: locals, statements: statements, location: location } end
def inspect -> String
# File prism/node.rb, line 15236 def inspect InspectVisitor.compose(self) 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 15254 def type :program_node end