Ruby 2.7.0-preview2 Released

_data/downloads.yml

@@ -4,7 +4,7 @@
 # optional
 preview:
 
-  - 2.7.0-preview1
+  - 2.7.0-preview2
 
 stable:
 

_data/releases.yml

@@ -21,6 +21,20 @@
 
 # 2.7 series
 
+- version: 2.7.0-preview2
+  date: 2019-10-22
+  post: /en/news/2019/10/22/ruby-2-7-0-preview2-released/
+  url:
+    gz:  https://cache.ruby-lang.org/pub/ruby/2.7/ruby-2.7.0-preview2.tar.gz
+    zip: https://cache.ruby-lang.org/pub/ruby/2.7/ruby-2.7.0-preview2.zip
+    bz2: https://cache.ruby-lang.org/pub/ruby/2.7/ruby-2.7.0-preview2.tar.bz2
+    xz:  https://cache.ruby-lang.org/pub/ruby/2.7/ruby-2.7.0-preview2.tar.xz
+  sha256:
+    gz:  bda4b8dc340fad425c8099400fe3ef8e7393837d7e6e1bfae41843d1d938ebc4
+    zip: 81a240bead4438b064cb4cde562b483b82ec8e414bac057a6df43df5a247545c
+    bz2: 417c84346ba84d664a13833c94c6d9f888c89bb9bee9adf469580441eaede30b
+    xz:  fa39f088331f6d505154aa9d025aab177fdffedfbbabccd900b8c02e745bc077
+
 - version: 2.7.0-preview1
   date: 2019-05-30
   post: /en/news/2019/05/30/ruby-2-7-0-preview1-released/

en/news/_posts/2019-10-22-ruby-2-7-0-preview2-released.md

@@ -0,0 +1,244 @@
+---
+layout: news_post
+title: "Ruby 2.7.0-preview2 Released"
+author: "naruse"
+translator:
+date: 2019-10-22 12:00:00 +0000
+lang: en
+---
+
+We are pleased to announce the release of Ruby 2.7.0-preview2.
+
+A preview version is released to gather feedback for the final release planned to release on December. It introduces a number of new features and performance improvements, most notably:
+
+* Compaction GC
+* Pattern Matching
+* REPL improvement
+* Separation of positional and keyword arguments
+
+## Compaction GC
+
+This release introduces Compaction GC which can defragment a fragmented memory space.
+
+Some multi-threaded Ruby programs may cause memory fragmentation, leading to high memory usage and degraded speed.
+
+The `GC.compact` method is introduced for compacting the heap. This function compacts live objects in the heap so that fewer pages may be used, and the heap may be more CoW friendly. [#15626](https://bugs.ruby-lang.org/issues/15626)
+
+## Pattern Matching [Experimental]
+
+Pattern matching, widely used feature in functional programming languages, is introduced as an experimental feature. [#14912](https://bugs.ruby-lang.org/issues/14912)
+It can traverse a given object and assign its value if it matches a pattern.
+
+```ruby
+case JSON.parse('{...}', symbolize_names: true)
+in {name: "Alice", children: [{name: "Bob", age: age}]}
+  p age
+  ...
+end
+```
+
+For more details, please see [Pattern matching - New feature in Ruby 2.7](https://speakerdeck.com/k_tsj/pattern-matching-new-feature-in-ruby-2-dot-7).
+
+## REPL improvement
+
+`irb`, bundled interactive environment (REPL; Read-Eval-Print-Loop), now supports multi-line editing. It's powered by `reline`, `readline`-compatible pure Ruby implementation.
+It also provides rdoc integration. In `irb` you can display the reference for a given class, module, or method.  [#14683](https://bugs.ruby-lang.org/issues/14683), [#14787](https://bugs.ruby-lang.org/issues/14787), [#14918](https://bugs.ruby-lang.org/issues/14918)
+Besides, source lines shown at `binding.irb` and inspect results for core-class objects are now colorized.
+
+<video autoplay="autoplay" controls="controls" muted="muted" width="576" height="259">
+  <source src="https://cache.ruby-lang.org/pub/media/irb_improved_with_key_take2.mp4" type="video/mp4">
+</video>
+
+## Separation of positional and keyword arguments
+
+Automatic conversion of keyword arguments and positional arguments is
+deprecated, and conversion will be removed in Ruby 3.  [[Feature #14183]](https://bugs.ruby-lang.org/issues/14183)
+
+  * When a method call passes a Hash at the last argument, and when it
+    passes no keywords, and when the called method accepts keywords, a
+    warning is emitted.  To continue treating as keywords, add a double
+    splat operator to avoid the warning and ensure correct behavior in
+    Ruby 3.
+
+    ```ruby
+    def foo(key: 42); end; foo({key: 42})   # warned
+    def foo(**kw);    end; foo({key: 42})   # warned
+    def foo(key: 42); end; foo(**{key: 42}) # OK
+    def foo(**kw);    end; foo(**{key: 42}) # OK
+    ```
+
+  * When a method call passes keywords to a method that accepts keywords,
+    but it does not pass enough required positional arguments, the
+    keywords are treated as a final required positional argument, and a
+    warning is emitted.  Pass the argument as a hash instead of keywords
+    to avoid the warning and ensure correct behavior in Ruby 3.
+
+    ```ruby
+    def foo(h, **kw); end; foo(key: 42)      # warned
+    def foo(h, key: 42); end; foo(key: 42)   # warned
+    def foo(h, **kw); end; foo({key: 42})    # OK
+    def foo(h, key: 42); end; foo({key: 42}) # OK
+    ```
+
+  * When a method accepts specific keywords but not a keyword splat, and
+    a hash or keywords splat is passed to the method that includes both
+    Symbol and non-Symbol keys, the hash will continue to be split, and
+    a warning will be emitted.  You will need to update the calling code
+    to pass separate hashes to ensure correct behavior in Ruby 3.
+
+    ```ruby
+    def foo(h={}, key: 42); end; foo("key" => 43, key: 42)   # warned
+    def foo(h={}, key: 42); end; foo({"key" => 43, key: 42}) # warned
+    def foo(h={}, key: 42); end; foo({"key" => 43}, key: 42) # OK
+    def foo(h={}, key: 42); end; foo({"key" => 43}, key: 42) # OK
+    ```
+
+  * If a method does not accept keywords, and is called with keywords,
+    the keywords are still treated as a positional hash, with no warning.
+    This behavior will continue to work in Ruby 3.
+
+    ```ruby
+    def foo(opt={});  end; foo( key: 42 )   # OK
+    ```
+
+* Non-symbols are allowed as a keyword argument keys if method accepts
+  arbitrary keywords.  [[Feature #14183]](https://bugs.ruby-lang.org/issues/14183)
+
+    ```ruby
+    def foo(**kw); p kw; end; foo("str" => 1) #=> {"str"=>1}
+    ```
+
+* <code>**nil</code> is allowed in method definitions to explicitly mark
+  that the method accepts no keywords. Calling such a method with keywords
+  will result in an ArgumentError.  [[Feature #14183]](https://bugs.ruby-lang.org/issues/14183)
+
+    ```ruby
+    def foo(h, **nil); end; foo(key: 1)       # ArgumentError
+    def foo(h, **nil); end; foo(**{key: 1})   # ArgumentError
+    def foo(h, **nil); end; foo("str" => 1)   # ArgumentError
+    def foo(h, **nil); end; foo({key: 1})     # OK
+    def foo(h, **nil); end; foo({"str" => 1}) # OK
+    ```
+
+* Passing an empty keyword splat to a method that does not accept keywords
+  no longer passes an empty hash, unless the empty hash is necessary for
+  a required parameter, in which case a warning will be emitted.  Remove
+  the double splat to continue passing a positional hash.  [[Feature #14183]](https://bugs.ruby-lang.org/issues/14183)
+
+    ```ruby
+    h = {}; def foo(*a) a end; foo(**h) # []
+    h = {}; def foo(a) a end; foo(**h)  # {} and warning
+    h = {}; def foo(*a) a end; foo(h)   # [{}]
+    h = {}; def foo(a) a end; foo(h)    # {}
+    ```
+
+## Other Notable New Features
+
+* A method reference operator, <code>.:</code>, is introduced as an experimental feature.  [#12125]( https://bugs.ruby-lang.org/issues/12125), [#13581]( https://bugs.ruby-lang.org/issues/13581)
+
+* Numbered parameter as the default block parameter is introduced as an experimental feature.  [#4475](https://bugs.ruby-lang.org/issues/4475)
+
+* A beginless range is experimentally introduced.  It might not be as useful
+  as an endless range, but would be good for DSL purpose. [#14799](https://bugs.ruby-lang.org/issues/14799)
+
+      ary[..3]  # identical to ary[0..3]
+      rel.where(sales: ..100)
+
+* `Enumerable#tally` is added.  It counts the occurrence of each element.
+
+      ["a", "b", "c", "b"].tally
+      #=> {"a"=>1, "b"=>2, "c"=>1}
+
+* Calling a private method on `self` is now allowed.  [Feature #11297] [Feature #16123]
+
+      def foo
+      end
+      private :foo
+      self.foo
+
+* `Enumerator::Lazy#eager` is added.  It generates a non-lazy enumerator
+  from a lazy enumerator.  [Feature #15901]
+
+      a = %w(foo bar baz)
+      e = a.lazy.map {|x| x.upcase }.map {|x| x + "!" }.eager
+      p e.class               #=> Enumerator
+      p e.map {|x| x + "?" }  #=> ["FOO!?", "BAR!?", "BAZ!?"]
+
+## Performance improvements
+
+* JIT [Experimental]
+
+  * JIT-ed code is recompiled to less-optimized code when an optimization assumption is invalidated.
+
+  * Method inlining is performed when a method is considered as pure. This optimization is still experimental and many methods are NOT considered as pure yet.
+
+  * Default value of `--jit-min-calls` is changed from 5 to 10,000
+
+  * Default value of `--jit-max-cache` is changed from 1,000 to 100
+
+* `Symbol#to_s`, `Module#name`, `true.to_s`, `false.to_s` and `nil.to_s` now always return a frozen String. The returned String is always the same for a given object. [Experimental]  [[Feature #16150]](https://bugs.ruby-lang.org/issues/16150)
+
+* The performance of CGI.escapeHTML is improved.
+  * https://github.com/ruby/ruby/pull/2226
+
+## Other notable changes since 2.6
+
+* Some standard libraries are updated.
+  * Bundler 2.1.0.pre.1
+  * RubyGems 3.1.0.pre.1
+  * CSV 3.1.2 ([NEWS](https://github.com/ruby/csv/blob/master/NEWS.md))
+  * Racc 1.4.15
+  * REXML 3.2.3 ([NEWS](https://github.com/ruby/rexml/blob/master/NEWS.md))
+  * RSS 0.2.8 ([NEWS](https://github.com/ruby/rss/blob/master/NEWS.md))
+  * StringScanner 1.0.3
+  * Some of other libraries that have no original version are also updated.
+
+* `Proc.new` and `proc` with no block in a method called with a block is warned now.
+
+* `lambda` with no block in a method called with a block errs.
+
+* Update Unicode version and Emoji version from 11.0.0 to 12.0.0.  [[Feature #15321]](https://bugs.ruby-lang.org/issues/15321)
+
+* Update Unicode version to 12.1.0, adding support for U+32FF SQUARE ERA NAME REIWA.  [[Feature #15195]](https://bugs.ruby-lang.org/issues/15195)
+
+* `Date.jisx0301`, `Date#jisx0301`, and `Date.parse` provisionally support the new Japanese era as an informal extension, until the new JIS X 0301 is issued.  [[Feature #15742]](https://bugs.ruby-lang.org/issues/15742)
+
+* Require compilers to support C99 [[Misc #15347]](https://bugs.ruby-lang.org/issues/15347)
+  * Details of our dialect: <https://bugs.ruby-lang.org/projects/ruby-trunk/wiki/C99>
+
+See [NEWS](https://github.com/ruby/ruby/blob/v2_7_0_preview1/NEWS) or [commit logs](https://github.com/ruby/ruby/compare/v2_6_0...v2_7_0_preview1) for more details.
+
+With those changes, [1727 files changed, 76022 insertions(+), 60286 deletions(-)](https://github.com/ruby/ruby/compare/v2_6_0...v2_7_0_preview1) since Ruby 2.6.0!
+
+Enjoy programming with Ruby 2.7!
+
+## Download
+
+* <https://cache.ruby-lang.org/pub/ruby/2.7/ruby-2.7.0-preview2.tar.bz2>
+
+      SIZE:   14555229 bytes
+      SHA1:   7d9eed71115acfc8851747517904c1c6809872a9
+      SHA256: 417c84346ba84d664a13833c94c6d9f888c89bb9bee9adf469580441eaede30b
+      SHA512: 7066ececebbbba4b2933ba1a4f70cdef373169910802259a3e52b4fc144ba298f3cffda4be5fe8a7be8ef769ed43076fa046a9ac2c13bb733475b9852112c6f0
+* <https://cache.ruby-lang.org/pub/ruby/2.7/ruby-2.7.0-preview2.tar.gz>
+
+      SIZE:   16622499 bytes
+      SHA1:   5e998eb37ef54e650c0206184d56f506359d5477
+      SHA256: bda4b8dc340fad425c8099400fe3ef8e7393837d7e6e1bfae41843d1d938ebc4
+      SHA512: dbf05d6ddab59062f507342b25b8c21670b02bdd49e77bda947870607f4bf9049e5e7ddfde6bbce2e1749ca92568da9be3e5f30601b1eb450f10d8add952239a
+* <https://cache.ruby-lang.org/pub/ruby/2.7/ruby-2.7.0-preview2.tar.xz>
+
+      SIZE:   11874200 bytes
+      SHA1:   4356e1726027795a5c6b08572bb37bcb5a8c55d6
+      SHA256: fa39f088331f6d505154aa9d025aab177fdffedfbbabccd900b8c02e745bc077
+      SHA512: a057a186d85fcdf123abd69d584ef3adb20ad4397521e14306395d34102c3d818fe2d34a6476db01effcde479da9a77076cbb6d30bca40f1471ce3f5d3a995a9
+* <https://cache.ruby-lang.org/pub/ruby/2.7/ruby-2.7.0-preview2.zip>
+
+      SIZE:   20576618 bytes
+      SHA1:   891b70ec76e9e776774a49b3ce24832a944422b3
+      SHA256: 81a240bead4438b064cb4cde562b483b82ec8e414bac057a6df43df5a247545c
+      SHA512: 1a8d4503374d31abf43182e2af6902ea6e5295f55d539415c8268b1d6a0fa83a975648c225ae986e687d5283dc2d180cf1e608841485506e4b0ac5efc154949a
+
+## What is Ruby
+
+Ruby was first developed by Matz (Yukihiro Matsumoto) in 1993, and is now developed as Open Source. It runs on multiple platforms and is used all over the world especially for web development.