Class: RuboCop::Cop::InternalAffairs::NodePatternGroups::ASTProcessor

Relationships & Source Files
Super Chains via Extension / Inclusion / Inheritance
Instance Chain: self, AST::Processor::Mixin
Inherits:	Object
Defined in:	lib/rubocop/cop/internal_affairs/node_pattern_groups/ast_processor.rb

Overview

AST Processor for NodePattern ASTs, for use with InternalAffairs/NodePatternGroups.

Looks for sequences and subsequences where the first item is a node_type node, and converts them to node_sequence nodes (not a true Rubocop::AST::NodePattern node type).

The resulting AST will be walked by ASTWalker in order to find node types in a union node that can be rewritten as a node group.

Note	The `on_*` methods in this class relate not to the normal node types but rather to the Node Pattern node types. Not every node type is handled.

Instance Method Summary

#handler_missing(node)
#on_sequence(node) (also: #on_subsequence)

Look for sequence and subsequence nodes that contain a node_type node as their first child.
#on_subsequence(node)

Alias for #on_sequence.
#n(type, children = [], properties = {}) private
#process_children(node, range = 0..-1)) private

Instance Method Details

#handler_missing(node)

[ GitHub ]

# File 'lib/rubocop/cop/internal_affairs/node_pattern_groups/ast_processor.rb', line 22


def handler_missing(node)
  node.updated(nil, process_children(node))
end

#n(type, children = [], properties = {}) (private)

[ GitHub ]

# File 'lib/rubocop/cop/internal_affairs/node_pattern_groups/ast_processor.rb', line 50


def n(type, children = [], properties = {})
  NodePattern::Node.new(type, children, properties)
end

#on_sequence(node) Also known as: #on_subsequence

Look for sequence and subsequence nodes that contain a node_type node as their first child. These are rewritten as node_sequence nodes so that it is possible to compare nodes while looking for replacement candidates for node groups. This is necessary so that extended patterns can be matched and replaced. ie. {(send _ :foo …) (csend _ :foo …)} can become (call _ :foo …)

[ GitHub ]

# File 'lib/rubocop/cop/internal_affairs/node_pattern_groups/ast_processor.rb', line 31


def on_sequence(node)
  first_child = node.child

  if first_child.type == :node_type
    children = [first_child.child, *process_children(node, 1..)]

    # The `node_sequence` node contains the `node_type` symbol as its first child,
    # followed by all the other nodes contained in the `sequence` node.
    # The location is copied from the sequence, so that the entire sequence can
    # eventually be corrected in the cop.
    n(:node_sequence, children, location: node.location)
  else
    node.updated(nil, process_children(node))
  end
end

#on_subsequence(node)

Alias for #on_sequence.

[ GitHub ]

# File 'lib/rubocop/cop/internal_affairs/node_pattern_groups/ast_processor.rb', line 46


alias on_subsequence on_sequence

#process_children(node, range = 0..-1)) (private)

[ GitHub ]

# File 'lib/rubocop/cop/internal_affairs/node_pattern_groups/ast_processor.rb', line 54


def process_children(node, range = 0..-1)
  node.children[range].map do |child|
    child.is_a?(::AST::Node) ? process(child) : child
  end
end