puppetlabs-stdlib/lib/puppet/parser/functions/parseyaml.rb

#
# parseyaml.rb
#

module Puppet::Parser::Functions
  newfunction(:parseyaml, :type => :rvalue, :doc => <<-EOS
This function accepts YAML as a string and converts it into the correct
Puppet structure.

The optional second argument can be used to pass a default value that will
be returned if the parsing of YAML string have failed.
  EOS
  ) do |arguments|
    raise ArgumentError, 'Wrong number of arguments. 1 or 2 arguments should be provided.' unless arguments.length >= 1
    require 'yaml'

    begin
      YAML::load(arguments[0]) || arguments[1]
      # in ruby 1.9.3 Psych::SyntaxError is a RuntimeException
      # this still needs to catch that and work also on rubies that
      # do not have Psych available.
    rescue StandardError, Psych::SyntaxError => e
      if arguments[1]
        arguments[1]
      else
        raise e
      end
    end

  end
end

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