Ruby 2.7.0-preview1 Released

We are pleased to announce the release of Ruby 2.7.0-preview1.

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

Compaction GC

This release introduces Compaction GC which can defragment a fragmented memory space.

Some multithread 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

Pattern Matching [Experimental]

Pattern matching, widely used feature in functional programming languages, is introduced as an experimental feature. #14912 It can traverse a given object and assign its value if it matches a pattern.

case JSON.parse('{...}', symbolize_names: true)
in {name: "Alice", children: [{name: "Bob", age: age}]}
  p age

For more details, please see Pattern matching - New feature in Ruby 2.7.

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, #14787, #14918 Besides, source lines shown at binding.irb and inspect results for core-class objects are now colorized.

Other Notable New Features

  • A method reference operator, .:, is introduced as an experimental feature. #12125, #13581

  • Numbered parameter as the default block parameter is introduced as an experimental feature. #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

    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}

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

Other notable changes since 2.6

  • 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]

  • Update Unicode version to 12.1.0, adding support for U+32FF SQUARE ERA NAME REIWA. [Feature #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]

  • Require compilers to support C99 [Misc #15347]

See NEWS or commit logs for more details.

With those changes, 1727 files changed, 76022 insertions(+), 60286 deletions(-) since Ruby 2.6.0!

Enjoy programming with Ruby 2.7!



    SIZE:   16021286 bytes
    SHA1:   2fbecf42b03a9d4391b81de42caec7fa497747cf
    SHA256: c44500af4a4a0c78a0b4d891272523f28e21176cf9bc1cc108977c5f270eaec2
    SHA512: f731bc9002edd3a61a4955e4cc46a75b5ab687a19c7964f02d3b5b07423d2360d25d7be5df340e884ca9945e3954e68e5eb11b209b65b3a687c71a1abc24b91f

    SIZE:   20283343 bytes
    SHA1:   7488346fa8e58203a38158752d03c8be6b1da65b
    SHA256: fdf25573e72e1769b51b8d541d0e1a894a5394dbfdf1b08215aa093079cca64c
    SHA512: b3b1f59dce94c242ef88a4e68381a4c3a6f90ba0af699083e5a1a00b0fb1dce580f057dad25571fe789ac9aa95aa6e9c071ebb330328dc822217ac9ea9fbeb3f

    SIZE:   14038296 bytes
    SHA1:   f7e70cbc2604c53a9e818a2fc59cd0e2d6c859fa
    SHA256: d45b4a1712ec5c03a35e85e33bcb57c7426b856d35e4f04f7975ae3944d09952
    SHA512: a36b241fc1eccba121bb7c2cc5675b11609e0153e25a3a8961b67270c05414b1aa669ce5d4a5ebe4c6b2328ea2b8f8635fbba046b70de103320b3fdcb3d51248

    SIZE:   11442988 bytes
    SHA1:   45e467debc194847a9e3afefb20b11e6dc28ea31
    SHA256: 8c546df3345398b3edc9d0ab097846f033783d33762889fd0f3dc8bb465c3354
    SHA512: d416e90bfa3e49cc0675c4c13243c8ec319b7a0836add1bd16bd7662d09eaf46656d26e772ef3b097e10779896e643edd8a6e4f885147e3235257736adfdf3b5

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.