hashie/lib/hashie/clash.rb

99 lines
2.8 KiB
Ruby

require 'hashie/hash'
module Hashie
#
# A Clash is a "Chainable Lazy Hash". Inspired by libraries such as Arel,
# a Clash allows you to chain together method arguments to build a
# hash, something that's especially useful if you're doing something
# like constructing a complex options hash. Here's a basic example:
#
# c = Hashie::Clash.new.conditions(:foo => 'bar').order(:created_at)
# c # => {:conditions => {:foo => 'bar'}, :order => :created_at}
#
# Clash provides another way to create sub-hashes by using bang notation.
# You can dive into a sub-hash by providing a key with a bang and dive
# back out again with the _end! method. Example:
#
# c = Hashie::Clash.new.conditions!.foo('bar').baz(123)._end!.order(:created_at)
# c # => { conditions: { foo: 'bar', baz: 123 }, order: :created_at}
#
# Because the primary functionality of Clash is to build options objects,
# all keys are converted to symbols since many libraries expect symbols explicitly
# for keys.
#
class Clash < ::Hash
class ChainError < ::StandardError; end
# The parent Clash if this Clash was created via chaining.
attr_reader :_parent
# Initialize a new clash by passing in a Hash to
# convert and, optionally, the parent to which this
# Clash is chained.
def initialize(other_hash = {}, parent = nil)
@_parent = parent
other_hash.each_pair do |k, v|
self[k.to_sym] = v
end
end
# Jump back up a level if you are using bang method
# chaining. For example:
#
# c = Hashie::Clash.new.foo('bar')
# c.baz!.foo(123) # => c[:baz]
# c.baz!._end! # => c
def _end!
_parent
end
def id(*args) #:nodoc:
method_missing(:id, *args)
end
def merge_store(key, *args) #:nodoc:
case args.length
when 1
val = args.first
val = self.class.new(self[key]).merge(val) if self[key].is_a?(::Hash) && val.is_a?(::Hash)
else
val = args
end
self[key.to_sym] = val
self
end
def method_missing(name, *args) #:nodoc:
if args.empty? && name.to_s.end_with?('!')
key = name[0...-1].to_sym
case self[key]
when NilClass
self[key] = self.class.new({}, self)
when Clash
self[key]
when Hash
self[key] = self.class.new(self[key], self)
else
raise ChainError, 'Tried to chain into a non-hash key.'
end
elsif args.any?
merge_store(name, *args)
else
super
end
end
def respond_to_missing?(method_name, _include_private = false)
method_name = method_name.to_s
if method_name.end_with?('!')
key = method_name[0...-1].to_sym
[NilClass, Clash, Hash].include?(self[key].class)
else
true
end
end
end
end