class RuboCop::Cop::Style::RedundantCapitalW

%W(apple #{fruit} grape)
%w[shirt pants shoes]
%w/swim run bike/
# good
%W[door wall floor]
%W(cat dog pig)
# bad
@example
Checks for usage of the %W() syntax when %w() would do.

def on_array(node) 

def on_array(node)
  process(node, '%W')
end

def on_percent_literal(node) 

def on_percent_literal(node)
  return if requires_interpolation?(node)
  add_offense(node) do |corrector|
    src = node.loc.begin.source
    corrector.replace(node.loc.begin, src.tr('W', 'w'))
  end
end

def requires_interpolation?(node) 

def requires_interpolation?(node)
  node.child_nodes.any? do |string|
    string.dstr_type? || double_quotes_required?(string.source)
  end
end