How to recursively compress a hash, starting from the innermost values.

hashmaster.rb

#!/usr/bin/env ruby
# encoding: utf-8
hash_collector = {}
# Assign people
hash_collector["James"]	= {}
hash_collector["John"]	= {}
hash_collector["Bert"]	= {}
hash_collector["Ernie"]	= {}
# Assign roles
hash_collector["James"]["artist"]		= []
hash_collector["John"]["athlete"]		= []
hash_collector["John"]["dancer"]		= []
hash_collector["Bert"]["oenophile"]		= []
hash_collector["Ernie"]["oenophile"]	= []
# Assign gear
hash_collector["James"]["artist"].push "paintbrush"
hash_collector["John"]["athlete"].push "shoes"
hash_collector["John"]["dancer"].push "shoes"
hash_collector["Bert"]["oenophile"].push "red wine"
hash_collector["Bert"]["oenophile"].push "white wine"
hash_collector["Ernie"]["oenophile"].push "red wine"
hash_collector["Ernie"]["oenophile"].push "white wine"

hash_collector.keys.each do |key_person|
	puts "+- #{key_person}"
	hash_collector[key_person].keys.each do |key_profession|
		puts "| +- #{key_profession}"
		hash_collector[key_person][key_profession].each do |array_element|
			puts "| | +- #{array_element}"
		end
	end
end

=begin
############## Real Output ##############
+- James
| +- artist
| | +- paintbrush
+- John
| +- athlete
| | +- shoes
| +- dancer
| | +- shoes
+- Bert
| +- oenophile
| | +- red wine
| | +- white wine
+- Ernie
| +- oenophile
| | +- red wine
| | +- white wine
############## Desired Output ##############
+- James
| +- artist
| | +- paintbrush
+- John
| +- athlete,dancer
| | +- shoes
+- Bert,Ernie
| +- oenophile
| | +- red wine
| | +- white wine
=end