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637 строки
18 KiB
Plaintext
637 строки
18 KiB
Plaintext
# -*- rdoc -*-
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= NEWS for Ruby 2.7.0
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This document is a list of user visible feature changes made between
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releases except for bug fixes.
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Note that each entry is kept so brief that no reason behind or reference
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information is supplied with. For a full list of changes with all
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sufficient information, see the ChangeLog file or Redmine
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(e.g. <tt>https://bugs.ruby-lang.org/issues/$FEATURE_OR_BUG_NUMBER</tt>)
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== Changes since the 2.6.0 release
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=== Language changes
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==== Pattern matching
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* Pattern matching is introduced as an experimental feature. [Feature #14912]
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case [0, [1, 2, 3]]
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in [a, [b, *c]]
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p a #=> 0
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p b #=> 1
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p c #=> [2, 3]
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end
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case {a: 0, b: 1}
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in {a: 0, x: 1}
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:unreachable
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in {a: 0, b: var}
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p var #=> 1
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end
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json = <<END
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{
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"name": "Alice",
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"age": 30,
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"children": [{ "name": "Bob", "age": 2 }]
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}
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END
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if JSON.parse(json, symbolize_names: true) in
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{name: "Alice", children: [{name: "Bob", age: age}]}
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p age #=> 2
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end
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* See the following slides in detail
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* https://speakerdeck.com/k_tsj/pattern-matching-new-feature-in-ruby-2-dot-7
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==== The spec of keyword arguments is changed towards 3.0
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* Automatic conversion of keyword arguments and positional arguments is
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deprecated, and conversion will be removed in Ruby 3. [Feature #14183]
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* When a method call passes a Hash at the last argument, and when it
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passes no keywords, and when the called method accepts keywords, a
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warning is emitted. To continue treating as keywords, add a double
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splat operator to avoid the warning and ensure correct behavior in
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Ruby 3.
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def foo(key: 42); end; foo({key: 42}) # warned
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def foo(**kw); end; foo({key: 42}) # warned
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def foo(key: 42); end; foo(**{key: 42}) # OK
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def foo(**kw); end; foo(**{key: 42}) # OK
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* When a method call passes keywords to a method that accepts keywords,
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but it does not pass enough required positional arguments, the
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keywords are treated as a final required positional argument, and a
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warning is emitted. Pass the argument as a hash instead of keywords
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to avoid the warning and ensure correct behavior in Ruby 3.
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def foo(h, **kw); end; foo(key: 42) # warned
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def foo(h, key: 42); end; foo(key: 42) # warned
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def foo(h, **kw); end; foo({key: 42}) # OK
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def foo(h, key: 42); end; foo({key: 42}) # OK
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* When a method accepts specific keywords but not a keyword splat, and
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a hash or keywords splat is passed to the method that includes both
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Symbol and non-Symbol keys, the hash will continue to be split, and
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a warning will be emitted. You will need to update the calling code
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to pass separate hashes to ensure correct behavior in Ruby 3.
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def foo(h={}, key: 42); end; foo("key" => 43, key: 42) # warned
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def foo(h={}, key: 42); end; foo({"key" => 43, key: 42}) # warned
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def foo(h={}, key: 42); end; foo({"key" => 43}, key: 42) # OK
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def foo(h={}, key: 42); end; foo({"key" => 43}, key: 42) # OK
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* If a method does not accept keywords, and is called with keywords,
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the keywords are still treated as a positional hash, with no warning.
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This behavior will continue to work in Ruby 3.
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def foo(opt={}); end; foo( key: 42 ) # OK
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* Non-symbols are allowed as a keyword argument keys if method accepts
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arbitrary keywords. [Feature #14183]
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* Non-Symbol keys in a keyword arguments hash were prohibited in 2.6.0,
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but are now allowed again. [Bug #15658]
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def foo(**kw); p kw; end; foo("str" => 1) #=> {"str"=>1}
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* <code>**nil</code> is allowed in method definitions to explicitly mark
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that the method accepts no keywords. Calling such a method with keywords
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will result in an ArgumentError. [Feature #14183]
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def foo(h, **nil); end; foo(key: 1) # ArgumentError
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def foo(h, **nil); end; foo(**{key: 1}) # ArgumentError
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def foo(h, **nil); end; foo("str" => 1) # ArgumentError
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def foo(h, **nil); end; foo({key: 1}) # OK
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def foo(h, **nil); end; foo({"str" => 1}) # OK
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* Passing an empty keyword splat to a method that does not accept keywords
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no longer passes an empty hash, unless the empty hash is necessary for
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a required parameter, in which case a warning will be emitted. Remove
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the double splat to continue passing a positional hash. [Feature #14183]
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h = {}; def foo(*a) a end; foo(**h) # []
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h = {}; def foo(a) a end; foo(**h) # {} and warning
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h = {}; def foo(*a) a end; foo(h) # [{}]
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h = {}; def foo(a) a end; foo(h) # {}
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==== Numbered parameter
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* Numbered parameter as the default block parameter is introduced as an
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experimental feature. [Feature #4475]
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[1, 2, 10].map { _1.to_s(16) } #=> ["1", "2", "a"]
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==== proc/lambda without block is deprecated
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* Proc.new and Kernel#proc with no block in a method called with a block is
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warned now.
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def foo
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proc
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end
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foo { puts "Hello" } #=> warning: Capturing the given block using Proc.new is deprecated; use `&block` instead
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* Kernel#lambda with no block in a method called with a block raises an exception.
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def bar
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lambda
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end
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bar { puts "Hello" } #=> tried to create Proc object without a block (ArgumentError)
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==== Other miscellaneous changes
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* A beginless range is experimentally introduced. It might not be as useful
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as an endless range, but would be good for DSL purpose. [Feature #14799]
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ary[..3] # identical to ary[0..3]
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where(sales: ..100)
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* Setting <code>$;</code> to non-nil value is warned now. Use of it in
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String#split is warned too.
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* Setting <code>$,</code> to non-nil value is warned now. Use of it in
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Array#join is warned too.
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* Quoted here-document identifier must end within the same line.
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<<"EOS
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" # This had been warned since 2.4; Now it raises a SyntaxError
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EOS
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* The flip-flop syntax deprecation is reverted. [Feature #5400]
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* Comment lines can be placed between fluent dot now.
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foo
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# .bar
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.baz # => foo.baz
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* Calling a private method with a literal <code>self</code> as the receiver
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is now allowed. [Feature #11297] [Feature #16123]
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* Modifier rescue now operates the same for multiple assignment as single
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assignment:
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a, b = raise rescue [1, 2]
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# Previously parsed as: (a, b = raise) rescue [1, 2]
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# Now parsed as: a, b = (raise rescue [1, 2])
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* Method reference operator, <code>.:</code> is introduced as an
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experimental feature. [Feature #12125] [Feature #13581]
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* +yield+ in singleton class syntax is warned and will be deprecated later [Feature #15575].
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* Argument forwarding by <code>...</code> is introduced. [Feature #16253]
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def foo(...)
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bar(...)
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end
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All arguments to +foo+ are forwarded to +bar+, including keyword and
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block arguments.
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=== Core classes updates (outstanding ones only)
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Array::
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New method::
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* Added Array#intersection. [Feature #16155]
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Comparable::
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Modified method::
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* Comparable#clamp now accepts a Range argument. [Feature #14784]
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-1.clamp(0..2) #=> 0
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1.clamp(0..2) #=> 1
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3.clamp(0..2) #=> 2
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Complex::
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New method::
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* Added Complex#<=>. So 0 <=> 0i will not raise NoMethodError. [Bug #15857]
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Dir::
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Modified method::
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* Dir.glob and Dir.[] no longer allow NUL-separated glob pattern.
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Use Array instead. [Feature #14643]
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Encoding::
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New encoding::
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* Added new encoding CESU-8 [Feature #15931]
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Enumerable::
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New methods::
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* Added Enumerable#filter_map. [Feature #15323]
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[1, 2, 3].filter_map {|x| x.odd? ? x.to_s : nil } #=> ["1", "3"]
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* Added Enumerable#tally. [Feature #11076]
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["A", "B", "C", "B", "A"].tally #=> {"A"=>2, "B"=>2, "C"=>1}
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Enumerator::
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New methods::
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* Added Enumerator::Lazy#eager that generates a non-lazy enumerator
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from a lazy enumerator. [Feature #15901]
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a = %w(foo bar baz)
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e = a.lazy.map {|x| x.upcase }.map {|x| x + "!" }.eager
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p e.class #=> Enumerator
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p e.map {|x| x + "?" } #=> ["FOO!?", "BAR!?", "BAZ!?"]
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* Added Enumerator::Yielder#to_proc so that a Yielder object
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can be directly passed to another method as a block
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argument. [Feature #15618]
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Fiber::
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New method::
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* Added Fiber#raise that behaves like Fiber#resume but raises an
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exception on the resumed fiber. [Feature #10344]
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File::
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Modified method::
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* File.extname now returns a dot string at a name ending with a dot on
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non-Windows platforms. [Bug #15267]
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File.extname("foo.") #=> "."
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FrozenError::
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New method::
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* Added FrozenError#receiver to return the frozen object that
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modification was attempted on. To set this object when raising
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FrozenError in Ruby code, pass it as the second argument to
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FrozenError.new.
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GC::
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New method::
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* Added GC.compact method for compacting the heap.
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This function compacts live objects in the heap so that fewer pages may
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be used, and the heap may be more CoW friendly. [Feature #15626]
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Details on the algorithm and caveats can be found here:
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https://bugs.ruby-lang.org/issues/15626
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IO::
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New method::
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* Added IO#set_encoding_by_bom to check the BOM and set the external
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encoding. [Bug #15210]
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Integer::
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Modified method::
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* Integer#[] now supports range operation. [Feature #8842]
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0b01001101[2, 4] #=> 0b0011
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0b01001100[2..5] #=> 0b0011
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0b01001100[2...6] #=> 0b0011
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^^^^
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NilClass / TrueClass / FalseClass::
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Modified methods::
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* NilClass#to_s, TrueClass#to_s and FalseClass#to_s now always return a
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frozen String. The returned String is always the same for each of these
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values. This change is experimental. [Feature #16150]
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Module::
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New methods::
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* Added Module#const_source_location to retrieve the location where a
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constant is defined. [Feature #10771]
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* Added Module#ruby2_keywords for marking a method as passing keyword
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arguments through a regular argument splat, useful when delegating
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all arguments to another method in a way that can be backwards
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compatible with older Ruby versions. [Bug #16154]
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Modified methods::
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* Module#autoload? now takes an +inherit+ optional argument, like as
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Module#const_defined?. [Feature #15777]
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* Module#name now always returns a frozen String. The returned String is
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always the same for a given Module. This change is
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experimental. [Feature #16150]
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ObjectSpace::WeakMap::
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Modified method::
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* ObjectSpace::WeakMap#[]= now accepts special objects as either key or
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values. [Feature #16035]
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Regexp / String::
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* Update Unicode version and Emoji version from 11.0.0 to
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12.0.0. [Feature #15321]
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* Update Unicode version to 12.1.0, adding support for
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U+32FF SQUARE ERA NAME REIWA. [Feature #15195]
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RubyVM::
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Removed method::
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* +RubyVM.resolve_feature_path+ moved to
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<code>$LOAD_PATH.resolve_feature_path</code>. [Feature #15903] [Feature #15230]
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Symbol::
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Modified method::
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* Symbol#to_s now always returns a frozen String. The returned String
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is always the same for a given Symbol. This change is
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experimental. [Feature #16150]
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Time::
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New methods::
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* Added Time#ceil method. [Feature #15772]
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* Added Time#floor method. [Feature #15653]
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Modified method::
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* Time#inspect is separated from Time#to_s and it shows its sub
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second. [Feature #15958]
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UnboundMethod::
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New method::
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* Added UnboundMethod#bind_call method. [Feature #15955]
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<code>umethod.bind_call(obj, ...)</code> is semantically equivalent
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to <code>umethod.bind(obj).call(...)</code>. This idiom is used in
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some libraries to call a method that is overridden. The added
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method does the same without allocation of intermediate Method
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object.
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class Foo
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def add_1(x)
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x + 1
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end
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end
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class Bar < Foo
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def add_1(x) # override
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x + 2
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end
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end
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obj = Bar.new
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p obj.add_1(1) #=> 3
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p Foo.instance_method(:add_1).bind(obj).call(1) #=> 2
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p Foo.instance_method(:add_1).bind_call(obj, 1) #=> 2
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$LOAD_PATH::
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New method::
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* Added <code>$LOAD_PATH.resolve_feature_path</code>. [Feature #15903] [Feature #15230]
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=== Stdlib updates (outstanding ones only)
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Bundler::
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* Upgrade to Bundler 2.1.0.pre.1
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Bundled from https://github.com/bundler/bundler/commit/a53709556b95a914e874b22ed2116a46b0528852
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CGI::
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* CGI.escapeHTML becomes 2~5x faster when there's at least one escaped character.
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https://github.com/ruby/ruby/pull/2226
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CSV::
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* Upgrade to 3.1.2.
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See https://github.com/ruby/csv/blob/master/NEWS.md.
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Date::
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* Date.jisx0301, Date#jisx0301, and Date.parse support the new Japanese
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era. [Feature #15742]
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Delegator::
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* Object#DelegateClass accepts a block and module_evals it in the context
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of the returned class, similar to Class.new and Struct.new.
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ERB::
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* Prohibit marshaling ERB instance.
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IRB::
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* Introduce syntax highlight inspired by pry.gem to Binding#irb source lines,
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REPL input, and inspect output of some core-class objects.
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* Introduce multiline mode by Reline.
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* Show documents when completion.
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* Enable auto indent and save/load history by default.
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Net::FTP::
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* Add Net::FTP#features to check available features, and Net::FTP#option to
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enable/disable each of them. [Feature #15964]
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Net::IMAP::
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* Add Server Name Indication (SNI) support. [Feature #15594]
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open-uri::
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* Warn open-uri's "open" method at Kernel.
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Use URI.open instead. [Misc #15893]
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* The default charset of text/* media type is UTF-8 instead of
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ISO-8859-1. [Bug #15933]
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OptionParser::
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* Now show "Did you mean?" for unknown option. [Feature #16256]
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test.rb:
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require 'optparse'
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OptionParser.new do |opts|
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opts.on("-f", "--foo", "foo") {|v| }
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opts.on("-b", "--bar", "bar") {|v| }
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opts.on("-c", "--baz", "baz") {|v| }
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end.parse!
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example:
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$ ruby test.rb --baa
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Traceback (most recent call last):
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test.rb:7:in `<main>': invalid option: --baa (OptionParser::InvalidOption)
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Did you mean? baz
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bar
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Pathname::
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* Delegates 3 arguments from Pathname.glob to Dir.glob to
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accept base: keyword.
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Racc::
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* Merge 1.4.15 from upstream repository and added cli of racc.
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Reline::
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* New stdlib that is compatible with readline stdlib by pure Ruby and also
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has a multiline mode.
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REXML::
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* Upgrade to 3.2.3.
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See https://github.com/ruby/rexml/blob/master/NEWS.md.
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RSS::
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* Upgrade to RSS 0.2.8.
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See https://github.com/ruby/rss/blob/master/NEWS.md.
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RubyGems::
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* Upgrade to RubyGems 3.1.0.pre1
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Bundled from https://github.com/rubygems/rubygems/commit/97b264f0fa248c864b6ee9a23d3ff1cdd217dddb
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StringScanner::
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* Upgrade to 1.0.3.
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See https://github.com/ruby/strscan/blob/master/NEWS.md.
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=== Compatibility issues (excluding feature bug fixes)
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* The following libraries are no longer bundled gems.
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Install corresponding gems to use these features.
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* CMath (cmath gem)
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* Scanf (scanf gem)
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* Shell (shell gem)
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* Synchronizer (sync gem)
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* ThreadsWait (thwait gem)
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Proc::
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* Proc#to_s format was changed. [Feature #16101]
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|
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=== Stdlib compatibility issues (excluding feature bug fixes)
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pathname::
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|
|
* Kernel#Pathname when called with a Pathname argument now returns
|
|
the argument instead of creating a new Pathname. This is more
|
|
similar to other Kernel methods, but can break code that modifies
|
|
the return value and expects the argument not to be modified.
|
|
|
|
profile.rb, Profiler__::
|
|
|
|
* Removed from standard library. No one maintains it from Ruby 2.0.0.
|
|
|
|
=== C API updates
|
|
|
|
* Many <code>*_kw</code> functions have been added for setting whether
|
|
the final argument being passed should be treated as keywords. You
|
|
may need to switch to these functions to avoid keyword argument
|
|
separation warnings, and to ensure correct behavior in Ruby 3.
|
|
|
|
* The <code>:</code> character in rb_scan_args format string is now
|
|
treated as keyword arguments. Passing a positional hash instead of
|
|
keyword arguments will emit a deprecation warning.
|
|
|
|
* C API declarations with +ANYARGS+ are changed not to use +ANYARGS+
|
|
https://github.com/ruby/ruby/pull/2404
|
|
|
|
=== Implementation improvements
|
|
|
|
Fiber::
|
|
|
|
* Allow selecting different coroutine implementation by using
|
|
`--with-coroutine=`, e.g.
|
|
|
|
./configure --with-coroutine=ucontext
|
|
./configure --with-coroutine=copy
|
|
|
|
* Replace previous stack cache with fiber pool cache. The fiber pool
|
|
allocates many stacks in a single memory region. Stack allocation
|
|
becomes O(log N) and fiber creation is amortized O(1). Around 10x
|
|
performance improvement was measured in micro-benchmarks.
|
|
|
|
File::
|
|
* File.realpath now uses realpath(3) on many platforms, which can
|
|
significantly improve performance.
|
|
|
|
Hash::
|
|
* Change data structure of small Hash objects. [Feature #15602]
|
|
|
|
Monitor::
|
|
* Monitor class is written in C-extension. [Feature #16255]
|
|
|
|
Thread::
|
|
|
|
* VM stack memory allocation is now combined with native thread stack,
|
|
improving thread allocation performance and reducing allocation related
|
|
failures. ~10x performance improvement was measured in micro-benchmarks.
|
|
|
|
JIT::
|
|
|
|
* 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-max-cache+ is changed from 1,000 to 100
|
|
|
|
* Default value of +--jit-min-calls+ is changed from 5 to 10,000
|
|
|
|
=== Miscellaneous changes
|
|
|
|
* Support for IA64 architecture has been removed. Hardware for testing was
|
|
difficult to find, native fiber code is difficult to implement, and it added
|
|
non-trivial complexity to the interpreter. [Feature #15894]
|
|
|
|
* Require compilers to support C99 [Misc #15347]
|
|
|
|
* Details of our dialect: https://bugs.ruby-lang.org/projects/ruby-trunk/wiki/C99
|
|
|
|
* Ruby's upstream repository is changed from Subversion to Git.
|
|
|
|
* https://git.ruby-lang.org/ruby.git
|
|
|
|
* RUBY_REVISION class is changed from Integer to String.
|
|
|
|
* RUBY_DESCRIPTION includes Git revision instead of Subversion's one.
|