nest merge hashes

nested_merge.rb

h1 = {:key => {a: 1, b: 2, c: {a: 1, b: 2}}}
h2 = {:key => {c: {a:'a', c: 'c'}, d: 4}}

recursive_merge = lambda do |k, old, new| 
  (new.respond_to?(:merge) && old.respond_to?(:merge)) ? new.merge(old, &recursive_merge) : new
end
puts h1.merge(h2, &recursive_merge)
# => {:key=>{:a=>1, :b=>2, :c=>{:a=>"a", :b=>2, :c=>"c"}, :d=>4}}

Oops thx Matt, still, is that the best way?

Yeah, I can't think of anything substantially better at present aside from defining a method on Hash. Run with it! :)

Y combinator! I'll try after sleeping some :)