deep_merge.rb
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deep_merge.rb
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	#
	# deep_merge.rb
	#
	module Puppet::Parser::Functions
	newfunction(:deep_merge, :type => :rvalue, :doc => <<-'ENDHEREDOC') do \|args\|
	Recursively merges two or more hashes together and returns the resulting hash.

	For example:

	$hash1 = {'one' => 1, 'two' => 2, 'three' => { 'four' => 4 } }
	$hash2 = {'two' => 'dos', 'three' => { 'five' => 5 } }
	$merged_hash = deep_merge($hash1, $hash2)
	# The resulting hash is equivalent to:
	# $merged_hash = { 'one' => 1, 'two' => 'dos', 'three' => { 'four' => 4, 'five' => 5 } }

	When there is a duplicate key that is a hash, they are recursively merged.
	When there is a duplicate key that is not a hash, the key in the rightmost hash will "win."

	ENDHEREDOC

	if args.length < 2
	raise Puppet::ParseError, "deep_merge(): wrong number of arguments (#{args.length}; must be at least 2)"
	end

	deep_merge = proc do \|hash1, hash2\|
	hash1.merge(hash2) do \|_key, old_value, new_value\|
	if old_value.is_a?(Hash) && new_value.is_a?(Hash)
	deep_merge.call(old_value, new_value)
	else
	new_value
	end
	end
	end

	result = {}
	args.each do \|arg\|
	next if arg.is_a?(String) && arg.empty? # empty string is synonym for puppet's undef
	# If the argument was not a hash, skip it.
	unless arg.is_a?(Hash)
	raise Puppet::ParseError, "deep_merge: unexpected argument type #{arg.class}, only expects hash arguments"
	end

	result = deep_merge.call(result, arg)
	end
	return(result)
	end
	end