require 'extlib/hash'
# This class has dubious semantics and we only have it so that people can write
# params[:key] instead of params['key'].
class Mash < Hash
# @param constructor<Object>
# The default value for the mash. Defaults to an empty hash.
#
# @details [Alternatives]
# If constructor is a Hash, a new mash will be created based on the keys of
# the hash and no default value will be set.
def initialize(constructor = {})
if constructor.is_a?(Hash)
super()
update(constructor)
else
super(constructor)
end
end
# @param key<Object> The default value for the mash. Defaults to nil.
#
# @details [Alternatives]
# If key is a Symbol and it is a key in the mash, then the default value will
# be set to the value matching the key.
def default(key = nil)
if key.is_a?(Symbol) && include?(key = key.to_s)
self[key]
else
super
end
end
alias_method :regular_writer, :[]= unless method_defined?(:regular_writer)
alias_method :regular_update, :update unless method_defined?(:regular_update)
# @param key<Object> The key to set.
# @param value<Object>
# The value to set the key to.
#
# @see Mash#convert_key
# @see Mash#convert_value
def []=(key, value)
regular_writer(convert_key(key), convert_value(value))
end
# @param other_hash<Hash>
# A hash to update values in the mash with. The keys and the values will be
# converted to Mash format.
#
# @return [Mash] The updated mash.
def update(other_hash)
other_hash.each_pair { |key, value| regular_writer(convert_key(key), convert_value(value)) }
self
end
alias_method :merge!, :update
# @param key<Object> The key to check for. This will be run through convert_key.
#
# @return [Boolean] True if the key exists in the mash.
def key?(key)
super(convert_key(key))
end
# def include? def has_key? def member?
alias_method :include?, :key?
alias_method :has_key?, :key?
alias_method :member?, :key?
# @param key<Object> The key to fetch. This will be run through convert_key.
# @param *extras<Array> Default value.
#
# @return [Object] The value at key or the default value.
def fetch(key, *extras)
super(convert_key(key), *extras)
end
# @param *indices<Array>
# The keys to retrieve values for. These will be run through +convert_key+.
#
# @return [Array] The values at each of the provided keys
def values_at(*indices)
indices.collect {|key| self[convert_key(key)]}
end
# @param hash<Hash> The hash to merge with the mash.
#
# @return [Mash] A new mash with the hash values merged in.
def merge(hash)
self.dup.update(hash)
end
# @param key<Object>
# The key to delete from the mash.\
def delete(key)
super(convert_key(key))
end
# @param *rejected<Array[(String, Symbol)] The mash keys to exclude.
#
# @return [Mash] A new mash without the selected keys.
#
# @example
# { :one => 1, :two => 2, :three => 3 }.except(:one)
# #=> { "two" => 2, "three" => 3 }
def except(*keys)
super(*keys.map {|k| convert_key(k)})
end
# Used to provide the same interface as Hash.
#
# @return [Mash] This mash unchanged.
def stringify_keys!; self end
# @return [Hash] The mash as a Hash with symbolized keys.
def symbolize_keys
h = Hash.new(default)
each { |key, val| h[key.to_sym] = val }
h
end
# @return [Hash] The mash as a Hash with string keys.
def to_hash
Hash.new(default).merge(self)
end
protected
# @param key<Object> The key to convert.
#
# @param [Object]
# The converted key. If the key was a symbol, it will be converted to a
# string.
#
# @api private
def convert_key(key)
key.kind_of?(Symbol) ? key.to_s : key
end
# @param value<Object> The value to convert.
#
# @return [Object]
# The converted value. A Hash or an Array of hashes, will be converted to
# their Mash equivalents.
#
# @api private
def convert_value(value)
if value.class == Hash
value.to_mash
elsif value.is_a?(Array)
value.collect { |e| convert_value(e) }
else
value
end
end
end