class Prism::Node

This represents a node in the tree. It is the parent class of all of the various node types.

Attributes

source[R]

A pointer to the source that this node was created from.

Public Class Methods

fields() click to toggle source

Returns a list of the fields that exist for this node class. Fields describe the structure of the node. This kind of reflection is useful for things like recursively visiting each node and field in the tree.

# File lib/prism/node.rb, line 127
def self.fields
  # This method should only be called on subclasses of Node, not Node
  # itself.
  raise NoMethodError, "undefined method `fields' for #{inspect}" if self == Node

  Reflection.fields_for(self)
end

Public Instance Methods

end_offset() click to toggle source

The end offset of the node in the source. This method is effectively a delegate method to the location object.

# File lib/prism/node.rb, line 34
def end_offset
  location = @location
  location.is_a?(Location) ? location.end_offset : ((location >> 32) + (location & 0xFFFFFFFF))
end

location() click to toggle source

A Location instance that represents the location of this node in the source.

# File lib/prism/node.rb, line 19
def location
  location = @location
  return location if location.is_a?(Location)
  @location = Location.new(source, location >> 32, location & 0xFFFFFFFF)
end

pretty_print(q) click to toggle source

Similar to inspect, but respects the current level of indentation given by the pretty print object.

# File lib/prism/node.rb, line 74
def pretty_print(q)
  q.seplist(inspect.chomp.each_line, -> { q.breakable }) do |line|
    q.text(line.chomp)
  end
  q.current_group.break
end

script_lines()

An alias for source_lines, used to mimic the API from RubyVM::AbstractSyntaxTree to make it easier to migrate.

Alias for: source_lines

slice() click to toggle source

Slice the location of the node from the source.

# File lib/prism/node.rb, line 61
def slice
  location.slice
end

slice_lines() click to toggle source

Slice the location of the node from the source, starting at the beginning of the line that the location starts on, ending at the end of the line that the location ends on.

# File lib/prism/node.rb, line 68
def slice_lines
  location.slice_lines
end

source_lines() click to toggle source

Returns all of the lines of the source code associated with this node.

# File lib/prism/node.rb, line 52
def source_lines
  location.source_lines
end

Also aliased as: script_lines

start_offset() click to toggle source

The start offset of the node in the source. This method is effectively a delegate method to the location object.

# File lib/prism/node.rb, line 27
def start_offset
  location = @location
  location.is_a?(Location) ? location.start_offset : location >> 32
end

to_dot() click to toggle source

Convert this node into a graphviz dot graph string.

# File lib/prism/node.rb, line 82
def to_dot
  # @type self: node
  DotVisitor.new.tap { |visitor| accept(visitor) }.to_dot
end

tunnel(line, column) click to toggle source

Returns a list of nodes that are descendants of this node that contain the given line and column. This is useful for locating a node that is selected based on the line and column of the source code.

Important to note is that the column given to this method should be in bytes, as opposed to characters or code units.

# File lib/prism/node.rb, line 93
def tunnel(line, column)
  queue = [self] #: Array[Prism::node]
  result = []

  while (node = queue.shift)
    result << node

    node.compact_child_nodes.each do |child_node|
      child_location = child_node.location

      start_line = child_location.start_line
      end_line = child_location.end_line

      if start_line == end_line
        if line == start_line && column >= child_location.start_column && column < child_location.end_column
          queue << child_node
          break
        end
      elsif (line == start_line && column >= child_location.start_column) || (line == end_line && column < child_location.end_column)
        queue << child_node
        break
      elsif line > start_line && line < end_line
        queue << child_node
        break
      end
    end
  end

  result
end

Node interface

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Public Class Methods

type() click to toggle source

Returns the type of the node as a symbol.

# File lib/prism/node.rb, line 179
def self.type
  raise NoMethodError, "undefined method `type' for #{inspect}"
end

Public Instance Methods

accept(visitor) click to toggle source

Accepts a visitor and calls back into the specialized visit function.

# File lib/prism/node.rb, line 143
def accept(visitor)
  raise NoMethodError, "undefined method `accept' for #{inspect}"
end

child_nodes() click to toggle source

Returns an array of child nodes, including ‘nil`s in the place of optional nodes that were not present.

# File lib/prism/node.rb, line 149
def child_nodes
  raise NoMethodError, "undefined method `child_nodes' for #{inspect}"
end

Also aliased as: deconstruct

comment_targets() click to toggle source

Returns an array of child nodes and locations that could potentially have comments attached to them.

# File lib/prism/node.rb, line 163
def comment_targets
  raise NoMethodError, "undefined method `comment_targets' for #{inspect}"
end

compact_child_nodes() click to toggle source

Returns an array of child nodes, excluding any ‘nil`s in the place of optional nodes that were not present.

# File lib/prism/node.rb, line 157
def compact_child_nodes
  raise NoMethodError, "undefined method `compact_child_nodes' for #{inspect}"
end

deconstruct()

Alias for: child_nodes

inspect() click to toggle source

Returns a string representation of the node.

# File lib/prism/node.rb, line 174
def inspect
  raise NoMethodError, "undefined method `inspect' for #{inspect}"
end

type() click to toggle source

Returns a symbol symbolizing the type of node that this represents. This is particularly useful for case statements and array comparisons.

# File lib/prism/node.rb, line 169
def type
  raise NoMethodError, "undefined method `type' for #{inspect}"
end