Class: RuboCop::Cop::InternalAffairs::NodePatternGroups::ASTWalker

Inherits:
Object
  • Object
show all
Defined in:
lib/rubocop/cop/internal_affairs/node_pattern_groups/ast_walker.rb

Overview

Walks an AST that has been processed by InternalAffairs::NodePatternGroups::Processor in order to find node_type and node_sequence nodes that can be replaced with a node group in InternalAffairs/NodePatternGroups.

Calling ‘ASTWalker#walk` sets node_groups with an array of NodeGroup structs that contain metadata about nodes that can be replaced, including location data. That metadata is used by the cop to register offenses and perform corrections.

Defined Under Namespace

Classes: NodeGroup

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize ⇒ ASTWalker

Returns a new instance of ASTWalker.



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# File 'lib/rubocop/cop/internal_affairs/node_pattern_groups/ast_walker.rb', line 30

def initialize
  reset!
end

Instance Attribute Details

#node_groups ⇒ Object (readonly)

Returns the value of attribute node_groups.



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# File 'lib/rubocop/cop/internal_affairs/node_pattern_groups/ast_walker.rb', line 38

def node_groups
  @node_groups
end

Instance Method Details

#on_union(node) ⇒ Object

Search union nodes for node_type and node_sequence nodes that can be collapsed into a node group.

  • node_type nodes are nodes with no further configuration (ie. send)

  • node_sequence nodes are nodes with further configuration (ie. ‘(send …)`)

Each group of types that can be collapsed will have a NodeGroup record added to node_groups, which is then used by the cop.



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# File 'lib/rubocop/cop/internal_affairs/node_pattern_groups/ast_walker.rb', line 59

def on_union(node)
  all_node_types = each_child_node(node, :node_type, :node_sequence).to_a

  each_node_group(all_node_types) do |group_name, node_types|
    next unless sequences_match?(node_types)

    node_groups << node_group_data(
      group_name, node, node_types,
      all_node_types.index(node_types.first),
      (node.children - node_types).any?
    )
  end
end

#reset! ⇒ Object 



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# File 'lib/rubocop/cop/internal_affairs/node_pattern_groups/ast_walker.rb', line 34

def reset!
  @node_groups = []
end

#walk(node) ⇒ Object

Recursively walk the AST in a depth-first manner. Only union nodes are handled further.



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# File 'lib/rubocop/cop/internal_affairs/node_pattern_groups/ast_walker.rb', line 42

def walk(node)
  return if node.nil?

  on_union(node) if node.type == :union

  node.child_nodes.each do |child|
    walk(child)
  end
end