Safe hash nesting

nested_hash.rb

class NestedHash < Hash
  
  def [](value, default = NestedHash.new)
    self.fetch(value, default)
  end

  def self.from_hash(other_hash)
    nested_hash = NestedHash.new
    other_hash.each_pair do |key, val|
      if val.is_a?(Hash)
        nested_hash[key] = NestedHash.from_hash(val)
      else
        nested_hash[key] = val
      end
    end
    return nested_hash
  end
end


# Setup a regular hash
h = NestedHash.new
h["elad"] = NestedHash.new
h["elad"]["adam"] = NestedHash.new
h["elad"]["adam"]["hungry"] = "always"

# Test non existing value
puts h["elad"]["miki"]["hungry", "no"] # => "no"

# Test Converstions from regular hashes
real_hash = {:elad => {:koko => :awesome}, :adam => {:moko => :no}}

nested = NestedHash.from_hash(real_hash)

# Missing Value
puts nested[:elad][:invalid_key, "not here"] # => "not here"

# Existing value
puts nested[:elad][:koko] # => "awesome"