map_to_hash.rb

module Enumerable
  
  def map_to_hash(&block)
    self.inject({}) do |acc, v|
      h = block.call(v)
      k = h.keys.first
      acc[k] = h[k]
      acc
    end 
  end 
  
end 

x = [:a, :b, :c].map_to_hash do |v|
  {v => v.to_s.upcase}
end 

puts x.inspect