[#100284] [Ruby master Bug#17211] Test failures in ruby2.7.2 and ruby3.0~preview1 — utkarsh@...

Issue #17211 has been reported by utkarsh (Utkarsh Gupta).

10 messages 2020/10/02

[#100301] [Ruby master Feature#17215] Backport for arm64 optimizations that exist for power/x86 — jaruga@...

Issue #17215 has been reported by jaruga (Jun Aruga).

10 messages 2020/10/05

[#100329] [Ruby master Bug#17220] Rails Active Job integration test fails with Ruby 3.0.0 since 2038cc6cab6ceeffef3ec3a765c70ae684f829ed — yasuo.honda@...

Issue #17220 has been reported by yahonda (Yasuo Honda).

28 messages 2020/10/07

[#100332] [Ruby master Bug#17221] Relax the Fiber#transfer's limitation — ko1@...

Issue #17221 has been reported by ko1 (Koichi Sasada).

15 messages 2020/10/07

[#100348] [Ruby master Bug#17257] Integer#pow(0, 1) returns 1, which is incorrect — universato@...

Issue #17257 has been reported by universato (Yoshimine Sato).

13 messages 2020/10/09

[#100371] [Ruby master Feature#17260] Promote pattern matching to official feature — kazuki@...

Issue #17260 has been reported by ktsj (Kazuki Tsujimoto).

10 messages 2020/10/11

[#100383] [Ruby master Feature#17261] Software transactional memory (STM) for Threads and Ractors — ko1@...

Issue #17261 has been reported by ko1 (Koichi Sasada).

14 messages 2020/10/12

[#100401] [Ruby master Bug#17263] Fiber context switch degrades with number of fibers, limit on number of fibers — ciconia@...

Issue #17263 has been reported by ciconia (Sharon Rosner).

14 messages 2020/10/15

[#100422] [CommonRuby Feature#17265] Add `Bool` module — marcandre-ruby-core@...

Issue #17265 has been reported by marcandre (Marc-Andre Lafortune).

11 messages 2020/10/19

[#100466] [Ruby master Feature#17273] shareable_constant_value pragma — ko1@...

Issue #17273 has been reported by ko1 (Koichi Sasada).

14 messages 2020/10/21

[#100471] [Ruby master Feature#17277] Make Enumerator#with_index yield row and col indices for Matrix — grzegorz.jakubiak@...

Issue #17277 has been reported by greggzst (Grzegorz Jakubiak).

8 messages 2020/10/21

[#100479] [Ruby master Feature#17278] On-demand sharing of constants for Ractor — daniel@...42.com

Issue #17278 has been reported by Dan0042 (Daniel DeLorme).

13 messages 2020/10/21

[#100534] [Ruby master Feature#17284] Shareable Proc — ko1@...

Issue #17284 has been reported by ko1 (Koichi Sasada).

16 messages 2020/10/25

[#100597] [Ruby master Feature#17288] Optimize __send__ call with a literal method name — muraken@...

Issue #17288 has been reported by mrkn (Kenta Murata).

13 messages 2020/10/27

[#100669] [Ruby master Feature#17295] Feature: Create a directory and file with Pathname#touch — get.codetriage@...

Issue #17295 has been reported by schneems (Richard Schneeman).

9 messages 2020/10/30

[#100673] [Ruby master Feature#17298] Ractor's basket communication APIs — ko1@...

Issue #17298 has been reported by ko1 (Koichi Sasada).

15 messages 2020/10/30

[#100675] [Ruby master Misc#17299] DevelopersMeeting20201120Japan — mame@...

Issue #17299 has been reported by mame (Yusuke Endoh).

11 messages 2020/10/31

[ruby-core:100507] [Ruby master Feature#17277] Make Enumerator#with_index yield row and col indices for Matrix

From: sawadatsuyoshi@...
Date: 2020-10-22 15:16:35 UTC
List: ruby-core #100507
Issue #17277 has been updated by sawa (Tsuyoshi Sawada).


I think the current behaviour is natural. You cannot play around with `with_index` since its receiver is `Enumerator`, not `Matrix`, and the information as a matrix is already gone.

You can retrieve the row and column indices easily from the flattened indices:

```ruby
m.each.with_index{|e, index| p index.divmod(m.column_size)}
[0, 0]
[0, 1]
[0, 2]
[0, 3]
[1, 0]
[1, 1]
[1, 2]
[1, 3]
[2, 0]
[2, 1]
[2, 2]
[2, 3]
```


----------------------------------------
Feature #17277: Make Enumerator#with_index yield row and col indices for Matrix
https://bugs.ruby-lang.org/issues/17277#change-88130

* Author: greggzst (Grzegorz Jakubiak)
* Status: Assigned
* Priority: Normal
* Assignee: marcandre (Marc-Andre Lafortune)
----------------------------------------
Given a matrix:

```ruby
matrix = Matrix[[0,2,3,4], [6,7,8,9], [1,4,5,8]]
```

You could get the row and col indices of a matrix using `Matrix#each_with_index`:

```ruby
matrix
.each_with_index { |e, row, col| p [row, col] }
[0, 0]
[0, 1]
[0, 2]
[0, 3]
[1, 0]
[1, 1]
[1, 2]
[1, 3]
[2, 0]
[2, 1]
[2, 2]
[2, 3] 
```

You can chain it with other enumerators and access indices within them:

```ruby
matrix
.each_with_index
.filter_map { |e, row, col| [row, col] if e % 4 == 0}
# => [[0, 0], [0, 3], [1, 2], [2, 1], [2, 3]]
```

Meanwhile, `with_index` after `Matrix#each` returns flattened indices, not row or column indices, which does not look right:

```ruby
matrix
.each.with_index { |e, index| p index }
0
1
2
3
4
5
6
7
8
9
10
11
```

I feel we should override `with_index` for `Matrix` so it returns row and column indices.



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