[#48745] [ruby-trunk - Bug #7267][Open] Dir.glob on Mac OS X returns unexpected string encodings for unicode file names — "kennygrant (Kenny Grant)" <kennygrant@...>

17 messages 2012/11/02

[#48773] [ruby-trunk - Bug #7269][Open] Refinement doesn't work if using locate after method — "ko1 (Koichi Sasada)" <redmine@...>

12 messages 2012/11/03

[#48847] [ruby-trunk - Bug #7274][Open] UnboundMethods should be bindable to any object that is_a?(owner of the UnboundMethod) — "rits (First Last)" <redmine@...>

21 messages 2012/11/04

[#48854] [ruby-trunk - Bug #7276][Open] TestFile#test_utime failure — "jonforums (Jon Forums)" <redmine@...>

14 messages 2012/11/04

[#48988] [ruby-trunk - Feature #7292][Open] Enumerable#to_h — "marcandre (Marc-Andre Lafortune)" <ruby-core@...>

40 messages 2012/11/06

[#48997] [ruby-trunk - Feature #7297][Open] map_to alias for each_with_object — "nathan.f77 (Nathan Broadbent)" <nathan.f77@...>

19 messages 2012/11/06

[#49001] [ruby-trunk - Bug #7298][Open] Behavior of Enumerator.new different between 1.9.3 and 2.0.0 — "ayumin (Ayumu AIZAWA)" <ayumu.aizawa@...>

12 messages 2012/11/06

[#49018] [ruby-trunk - Feature #7299][Open] Ruby should not completely ignore blocks. — "marcandre (Marc-Andre Lafortune)" <ruby-core@...>

13 messages 2012/11/07

[#49044] [ruby-trunk - Bug #7304][Open] Random test failures around test_autoclose_true_closed_by_finalizer — "luislavena (Luis Lavena)" <luislavena@...>

11 messages 2012/11/07

[#49196] [ruby-trunk - Feature #7322][Open] Add a new operator name #>< for bit-wise "exclusive or" — "alexeymuranov (Alexey Muranov)" <redmine@...>

18 messages 2012/11/10

[#49211] [ruby-trunk - Feature #7328][Open] Move ** operator precedence under unary + and - — "boris_stitnicky (Boris Stitnicky)" <boris@...>

20 messages 2012/11/11

[#49229] [ruby-trunk - Bug #7331][Open] Set the precedence of unary `-` equal to the precedence `-`, same for `+` — "alexeymuranov (Alexey Muranov)" <redmine@...>

17 messages 2012/11/11

[#49256] [ruby-trunk - Feature #7336][Open] Flexiable OPerator Precedence — "trans (Thomas Sawyer)" <transfire@...>

18 messages 2012/11/12

[#49354] review open pull requests on github — Zachary Scott <zachary@...>

Could we get a review on any open pull requests on github before the

12 messages 2012/11/15
[#49355] Re: review open pull requests on github — "NARUSE, Yui" <naruse@...> 2012/11/15

2012/11/15 Zachary Scott <[email protected]>:

[#49356] Re: review open pull requests on github — Zachary Scott <zachary@...> 2012/11/15

Ok, I was hoping one of the maintainers might want to.

[#49451] [ruby-trunk - Bug #7374][Open] File.expand_path resolving to first file/dir instead of absolute path — mdube@... (Martin Dubé) <mdube@...>

12 messages 2012/11/16

[#49463] [ruby-trunk - Feature #7375][Open] embedding libyaml in psych for Ruby 2.0 — "tenderlovemaking (Aaron Patterson)" <aaron@...>

21 messages 2012/11/16
[#49494] [ruby-trunk - Feature #7375] embedding libyaml in psych for Ruby 2.0 — "vo.x (Vit Ondruch)" <v.ondruch@...> 2012/11/17

[#49467] [ruby-trunk - Feature #7377][Open] #indetical? as an alias for #equal? — "aef (Alexander E. Fischer)" <aef@...>

13 messages 2012/11/17

[#49558] [ruby-trunk - Bug #7395][Open] Negative numbers can't be primes by definition — "zzak (Zachary Scott)" <zachary@...>

10 messages 2012/11/19

[#49566] [ruby-trunk - Feature #7400][Open] Incorporate OpenSSL tests from JRuby. — "zzak (Zachary Scott)" <zachary@...>

11 messages 2012/11/19

[#49770] [ruby-trunk - Feature #7414][Open] Now that const_get supports "Foo::Bar" syntax, so should const_defined?. — "robertgleeson (Robert Gleeson)" <rob@...>

9 messages 2012/11/20

[#49950] [ruby-trunk - Feature #7427][Assigned] Update Rubygems — "mame (Yusuke Endoh)" <mame@...>

17 messages 2012/11/24

[#50043] [ruby-trunk - Bug #7429][Open] Provide options for core collections to customize behavior — "headius (Charles Nutter)" <headius@...>

10 messages 2012/11/24

[#50092] [ruby-trunk - Feature #7434][Open] Allow caller_locations and backtrace_locations to receive negative params — "sam.saffron (Sam Saffron)" <sam.saffron@...>

21 messages 2012/11/25

[#50094] [ruby-trunk - Bug #7436][Open] Allow for a "granularity" flag for backtrace_locations — "sam.saffron (Sam Saffron)" <sam.saffron@...>

11 messages 2012/11/25

[#50207] [ruby-trunk - Bug #7445][Open] strptime('%s %z') doesn't work — "felipec (Felipe Contreras)" <felipe.contreras@...>

19 messages 2012/11/27

[#50424] [ruby-trunk - Bug #7485][Open] ruby cannot build on mingw32 due to missing __sync_val_compare_and_swap — "drbrain (Eric Hodel)" <[email protected]>

15 messages 2012/11/30

[#50429] [ruby-trunk - Feature #7487][Open] Cutting through the issues with Refinements — "trans (Thomas Sawyer)" <transfire@...>

13 messages 2012/11/30

[ruby-core:50221] [ruby-trunk - Feature #7444] Array#product_set

From: "trans (Thomas Sawyer)" <transfire@...>
Date: 2012-11-27 13:05:51 UTC
List: ruby-core #50221
Issue #7444 has been updated by trans (Thomas Sawyer).


I'd prefer `Array.product`, all things being the same.

But you have given me a neat idea. In Ruby Facets there is a method Enumerable#every. It works like so:

  [1,2,3].every + 2  #=> [3,4,5]
  [1,2,3].every * 2  #=> [2,4,6]

#every is a HOM (a higher-order method). You made me realize another good form of this would be one that applies to each new result. I am not sure what a good name for it would be, but for the moment lets just call it #apply. Then in your case of #product.

  deck.apply.product  #=> [[1, :spades], [2, :spades], ...]

Only problem is I haven't had any success it getting the Ruby gods to come around on HOMs :(

----------------------------------------
Feature #7444: Array#product_set
https://bugs.ruby-lang.org/issues/7444#change-34038

Author: marcandre (Marc-Andre Lafortune)
Status: Open
Priority: Normal
Assignee: matz (Yukihiro Matsumoto)
Category: core
Target version: next minor


I'd like to propose `Array#product_set` to return the product set of arrays (aka cartesian product)

    deck = [1..13, %i(spades hearts diamond clubs)].product_set
        # => <#Enumerator ...>
    deck.first(2) # => [[1, :spades], [2, :spades]]

`product_set` would return an enumerator if no block is given. It should raise an error if an element of the array is not an Enumerable, like Array#transpose or #zip do.

Although `Array.product` would be acceptable too, I feel that an instance method of array is best in the case, in the same way that `transpose` is an instance method and not a class method.

The name "product_set" is a correct mathematical term. Although the synonym "cartesian_product" would also be acceptable, I propose "product_set" because it is shorter and cute too. I feel it is even clearer than `product`; the first time I head of `product` I was convinced that `[2,3,7].product # => 42`.

Addressing objections raised in #6499:

1) This is not for the sake of symmetry, but because often we have an array of the arrays we want a product of.

It is cumbersome to write `arrays.first.product(*arrays[1..-1])` or similar and it hides what is going on.

Writing `arrays.product_set` is much nicer.

2) The goal is not mainly to get a lazy version, but more to make the API better. The fact that it returns an Enumerator if no block is given is just a bonus :-)

3) [].product_set.to_a # => [[]]

This can be seen from a cardinality argument, or for example because `array.repeated_permutation(n) == Array.new(n, array).product_set.to_a` and `array.repeated_permutation(0) == [[]]`.



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