class RuboCop::Cop::InternalAffairs::NodePatternGroups::ASTProcessor


rather to the Node Pattern node types. Not every node type is handled.
NOTE: The ‘on_*` methods in this class relate not to the normal node types but
in order to find node types in a `union` node that can be rewritten as a node group.
The resulting AST will be walked by `InternalAffairs::NodePatternGroups::ASTWalker`
node type).
and converts them to `node_sequence` nodes (not a true `Rubocop::AST::NodePattern`
Looks for sequences and subsequences where the first item is a `node_type` node,
AST Processor for NodePattern ASTs, for use with `InternalAffairs/NodePatternGroups`.

def handler_missing(node) 

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

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

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

def on_sequence(node)

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

def process_children(node, range = 0..-1) 

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