# YAML Ain't Markup Language
#
# This module provides a Ruby interface for data serialization in YAML format.
#
# You can choose from one of two YAML engines that ship with Ruby 1.9. By
# default Psych is used but the old unmaintained Syck may chosen.
#
# == Usage
#
# Working with YAML can be very simple, for example:
#
# require 'yaml' # STEP ONE, REQUIRE YAML!
# # Parse a YAML string
# YAML.load("--- foo") #=> "foo"
#
# # Emit some YAML
# YAML.dump("foo") # => "--- foo\n...\n"
# { :a => 'b'}.to_yaml # => "---\n:a: b\n"
#
# == Security
#
# Do not use YAML to load untrusted data. Doing so is unsafe and could allow
# malicious input to execute arbitrary code inside your application. Please see
# doc/security.rdoc for more information.
#
# == Syck
#
# Syck was the original for YAML implementation in Ruby's standard library
# developed by why the lucky stiff.
#
# If you prefer, you can still use Syck by changing the YAML::ENGINE like so:
#
# YAML::ENGINE.yamler = 'syck'
# # switch back to the default Psych
# YAML::ENGINE.yamler = 'psych'
#
# In older Ruby versions, ie. <= 1.9, Syck is still provided, however it was
# completely removed with the release of Ruby 2.0.0.
#
# == More info
#
# For more advanced details on the implementation see Psych, and also check out
# http://yaml.org for spec details and other helpful information.
module YAML
class EngineManager # :nodoc:
attr_reader :yamler
def initialize
@yamler = nil
end
def syck?
'syck' == @yamler
end
def yamler= engine
raise(ArgumentError, "bad engine") unless %w{syck psych}.include?(engine)
require engine unless (engine == 'syck' ? Syck : Psych).const_defined?(:VERSION)
Object.class_eval <<-eorb, __FILE__, __LINE__ + 1
remove_const 'YAML'
YAML = #{engine.capitalize}
remove_method :to_yaml
alias :to_yaml :#{engine}_to_yaml
eorb
@yamler = engine
engine
end
end
##
# Allows changing the current YAML engine. See YAML for details.
ENGINE = YAML::EngineManager.new # :nodoc:
end
if defined?(Psych)
engine = 'psych'
elsif defined?(Syck)
engine = 'syck'
else
begin
require 'psych'
engine = 'psych'
rescue LoadError
warn "#{caller[0]}:"
warn "It seems your ruby installation is missing psych (for YAML output)."
warn "To eliminate this warning, please install libyaml and reinstall your ruby."
require 'syck'
engine = 'syck'
end
end
module Syck # :nodoc:
ENGINE = YAML::ENGINE
end
module Psych # :nodoc:
ENGINE = YAML::ENGINE
end
YAML::ENGINE.yamler = engine
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