Permalink
Switch branches/tags
Find file Copy path
Fetching contributors…
Cannot retrieve contributors at this time
169 lines (153 sloc) 4.72 KB
# frozen_string_literal: true
module Enumerable
INDEX_WITH_DEFAULT = Object.new
private_constant :INDEX_WITH_DEFAULT
# Enumerable#sum was added in Ruby 2.4, but it only works with Numeric elements
# when we omit an identity.
# :stopdoc:
# We can't use Refinements here because Refinements with Module which will be prepended
# doesn't work well https://bugs.ruby-lang.org/issues/13446
alias :_original_sum_with_required_identity :sum
private :_original_sum_with_required_identity
# :startdoc:
# Calculates a sum from the elements.
#
# payments.sum { |p| p.price * p.tax_rate }
# payments.sum(&:price)
#
# The latter is a shortcut for:
#
# payments.inject(0) { |sum, p| sum + p.price }
#
# It can also calculate the sum without the use of a block.
#
# [5, 15, 10].sum # => 30
# ['foo', 'bar'].sum # => "foobar"
# [[1, 2], [3, 1, 5]].sum # => [1, 2, 3, 1, 5]
#
# The default sum of an empty list is zero. You can override this default:
#
# [].sum(Payment.new(0)) { |i| i.amount } # => Payment.new(0)
def sum(identity = nil, &block)
if identity
_original_sum_with_required_identity(identity, &block)
elsif block_given?
map(&block).sum(identity)
else
inject(:+) || 0
end
end
# Convert an enumerable to a hash keying it by the block return value.
#
# people.index_by(&:login)
# # => { "nextangle" => <Person ...>, "chade-" => <Person ...>, ...}
#
# people.index_by { |person| "#{person.first_name} #{person.last_name}" }
# # => { "Chade- Fowlersburg-e" => <Person ...>, "David Heinemeier Hansson" => <Person ...>, ...}
def index_by
if block_given?
result = {}
each { |elem| result[yield(elem)] = elem }
result
else
to_enum(:index_by) { size if respond_to?(:size) }
end
end
# Convert an enumerable to a hash keying it with the enumerable items and with the values returned in the block.
#
# post = Post.new(title: "hey there", body: "what's up?")
#
# %i( title body ).index_with { |attr_name| post.public_send(attr_name) }
# # => { title: "hey there", body: "what's up?" }
def index_with(default = INDEX_WITH_DEFAULT)
if block_given?
result = {}
each { |elem| result[elem] = yield(elem) }
result
elsif default != INDEX_WITH_DEFAULT
result = {}
each { |elem| result[elem] = default }
result
else
to_enum(:index_with) { size if respond_to?(:size) }
end
end
# Returns +true+ if the enumerable has more than 1 element. Functionally
# equivalent to <tt>enum.to_a.size > 1</tt>. Can be called with a block too,
# much like any?, so <tt>people.many? { |p| p.age > 26 }</tt> returns +true+
# if more than one person is over 26.
def many?
cnt = 0
if block_given?
any? do |element|
cnt += 1 if yield element
cnt > 1
end
else
any? { (cnt += 1) > 1 }
end
end
# The negative of the <tt>Enumerable#include?</tt>. Returns +true+ if the
# collection does not include the object.
def exclude?(object)
!include?(object)
end
# Returns a copy of the enumerable without the specified elements.
#
# ["David", "Rafael", "Aaron", "Todd"].without "Aaron", "Todd"
# # => ["David", "Rafael"]
#
# {foo: 1, bar: 2, baz: 3}.without :bar
# # => {foo: 1, baz: 3}
def without(*elements)
reject { |element| elements.include?(element) }
end
# Convert an enumerable to an array based on the given key.
#
# [{ name: "David" }, { name: "Rafael" }, { name: "Aaron" }].pluck(:name)
# # => ["David", "Rafael", "Aaron"]
#
# [{ id: 1, name: "David" }, { id: 2, name: "Rafael" }].pluck(:id, :name)
# # => [[1, "David"], [2, "Rafael"]]
def pluck(*keys)
if keys.many?
map { |element| keys.map { |key| element[key] } }
else
map { |element| element[keys.first] }
end
end
end
class Range #:nodoc:
# Optimize range sum to use arithmetic progression if a block is not given and
# we have a range of numeric values.
def sum(identity = nil)
if block_given? || !(first.is_a?(Integer) && last.is_a?(Integer))
super
else
actual_last = exclude_end? ? (last - 1) : last
if actual_last >= first
sum = identity || 0
sum + (actual_last - first + 1) * (actual_last + first) / 2
else
identity || 0
end
end
end
end
# Using Refinements here in order not to expose our internal method
using Module.new {
refine Array do
alias :orig_sum :sum
end
}
class Array #:nodoc:
# Array#sum was added in Ruby 2.4 but it only works with Numeric elements.
def sum(init = nil, &block)
if init.is_a?(Numeric) || first.is_a?(Numeric)
init ||= 0
orig_sum(init, &block)
else
super
end
end
end